U.S. patent application number 11/607103 was filed with the patent office on 2007-06-14 for copper alloy for electric and electronic instruments.
This patent application is currently assigned to THE FURUKAWA ELECTRIC CO., LTD.. Invention is credited to Tatsuhiko Eguchi, Hiroshi Kaneko, Kuniteru Mihara.
Application Number | 20070131321 11/607103 |
Document ID | / |
Family ID | 35462923 |
Filed Date | 2007-06-14 |
United States Patent
Application |
20070131321 |
Kind Code |
A1 |
Kaneko; Hiroshi ; et
al. |
June 14, 2007 |
Copper alloy for electric and electronic instruments
Abstract
A copper alloy for electric and electronic instruments,
containing Ni of 1 to 3 mass %, Ti of 0.2 to 1.2 mass %, any one or
both of Mg and Zr of 0.02 to 0.2 mass %, and Zn of 0.1 to 1 mass %,
with the balance being Cu and unavoidable impurities, in which the
copper alloy contains at least one of an intermetallic compound
comprising Ni, Ti and Mg, an intermetallic compound comprising Ni,
Ti and Zr, or an intermetallic compound comprising Ni, Ti, Mg and
Zr, and the copper alloy has a stress relaxation rate of 20% or
less after holding the alloy at 150.degree. C. for 1,000 hours; and
a method of producing the copper alloy for electric and electronic
instruments.
Inventors: |
Kaneko; Hiroshi; (Tokyo,
JP) ; Mihara; Kuniteru; (Tokyo, JP) ; Eguchi;
Tatsuhiko; (Tokyo, JP) |
Correspondence
Address: |
WESTERMAN, HATTORI, DANIELS & ADRIAN, LLP
1250 CONNECTICUT AVENUE, NW
SUITE 700
WASHINGTON
DC
20036
US
|
Assignee: |
THE FURUKAWA ELECTRIC CO.,
LTD.
Tokyo
JP
|
Family ID: |
35462923 |
Appl. No.: |
11/607103 |
Filed: |
December 1, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/JP05/10536 |
Jun 2, 2005 |
|
|
|
11607103 |
Dec 1, 2006 |
|
|
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Current U.S.
Class: |
148/685 ;
148/413; 420/473; 420/481 |
Current CPC
Class: |
H01R 13/03 20130101;
C22F 1/08 20130101; C22C 9/06 20130101; H01R 13/24 20130101; H01H
1/025 20130101 |
Class at
Publication: |
148/685 ;
148/413; 420/473; 420/481 |
International
Class: |
C22C 9/06 20060101
C22C009/06 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 2, 2004 |
JP |
2004-165068 |
Jun 1, 2005 |
JP |
2005-161475 |
Claims
1. A copper alloy for electric and electronic instruments,
comprising Ni of 1 to 3 mass %, Ti of 0.2 to 1.2 mass %, any one or
both of Mg and Zr of 0.02 to 0.2 mass %, and Zn of 0.1 to 1 mass %,
with the balance being Cu and unavoidable impurities, wherein the
copper alloy contains at least one of an intermetallic compound
comprising Ni, Ti and Mg, an intermetallic compound comprising Ni,
Ti and Zr, or an intermetallic compound comprising Ni, Ti, Mg and
Zr, and wherein the copper alloy has a stress relaxation rate of
20% or less after holding the alloy at 150.degree. C. for 1,000
hours.
2. The copper alloy for electric and electronic instruments
according to claim 1, wherein the intermetallic compound comprising
Ni, Ti and Mg, the intermetallic compound comprising Ni, Ti and Zr,
or the intermetallic compound comprising Ni, Ti, Mg and Zr has an
average particle diameter in the range from 5 to 100 nm and a
distribution density of from 1.times.10.sup.10 to
1.times.10.sup.13/mm.sup.2, and wherein the crystal grain size of a
host matrix of the alloy is 10 .mu.m or less.
3. A copper alloy for electric and electronic instruments,
comprising Ni of 1 to 3 mass %, Ti of 0.2 to 1.2 mass %, any one or
both of Sn and Si of 0.02 to 0.2 mass %, and Zn of 0.1 to 1 mass %,
with the balance being Cu and unavoidable impurities, wherein the
copper alloy contains at least one of an intermetallic compound
comprising Ni, Ti and Sn, an intermetallic compound comprising Ni,
Ti and Si, or an intermetallic compound comprising Ni, Ti, Sn and
Si, and wherein the copper alloy has a stress relaxation rate of
20% or less after holding the alloy at 150.degree. C. for 1,000
hours.
4. The copper alloy for electric and electronic instruments
according to claim 3, wherein the intermetallic compound comprising
Ni, Ti and Sn, the intermetallic compound comprising Ni, Ti and Si,
or the intermetallic compound comprising Ni, Ti, Sn and Si has an
average particle diameter in the range from 5 to 100 nm and a
distribution density of from 1.times.10.sup.10 to
1.times.10.sup.13/mm.sup.2, and wherein the crystal grain size of a
host matrix of the alloy is 10 .mu.m or less.
5-11. (canceled)
12. A method of producing the copper alloy for electric and
electronic instruments according to claim 1, comprising the steps
of: conducting a solution heat treatment at a temperature of
850.degree. C. or more for 35 seconds or less, cooling from the
solution heat treatment temperature to 300.degree. C. at a cooling
rate of 50.degree. C./sec or more, cold-rolling at a cold rolling
ratio in the range of more than 0% but 50% or less, and aging at a
temperature in the range from 450 to 600.degree. C. within 5
hours.
13. A method of producing the copper alloy for electric and
electronic instruments according to claim 2, comprising the steps
of: conducting a solution heat treatment at a temperature of
850.degree. C. or more for 35 seconds or less, cooling from the
solution heat treatment temperature to 300.degree. C. at a cooling
rate of 50.degree. C./sec or more, cold-rolling at a cold rolling
ratio in the range of more than 0% but 50% or less, and aging at a
temperature in the range from 450 to 600.degree. C. within 5
hours.
14. A method of producing the copper alloy for electric and
electronic instruments according to claim 3, comprising the steps
of: conducting a solution heat treatment at a temperature of
850.degree. C. or more for 35 seconds or less, cooling from the
solution heat treatment temperature to 300.degree. C. at a cooling
rate of 50.degree. C./sec or more, cold-rolling at a cold rolling
ratio in the range of more than 0% but 50% or less, and aging at a
temperature in the range from 450 to 600.degree. C. within 5
hours.
15. A method of producing the copper alloy for electric and
electronic instruments according to claim 4, comprising the steps
of: conducting a solution heat treatment at a temperature of
850.degree. C. or more for 35 seconds or less, cooling from the
solution heat treatment temperature to 300.degree. C. at a cooling
rate of 50.degree. C./sec or more, cold-rolling at a cold rolling
ratio in the range of more than 0% but 50% or less, and aging at a
temperature in the range from 450 to 600.degree. C. within 5
hours.
16. A method of producing the copper alloy for electric and
electronic instruments according to claim 1, comprising the steps
of: conducting a solution heat treatment at a temperature of
850.degree. C. or more for 35 seconds or less, cooling from the
solution heat treatment temperature to 300.degree. C. at a cooling
rate of 50.degree. C./sec or more, and aging at a temperature in
the range from 450 to 600.degree. C. within 5 hours.
17. A method of producing the copper alloy for electric and
electronic instruments according to claim 2, comprising the steps
of: conducting a solution heat treatment at a temperature of
850.degree. C. or more for 35 seconds or less, cooling from the
solution heat treatment temperature to 300.degree. C. at a cooling
rate of 50.degree. C./sec or more, and aging at a temperature in
the range from 450 to 600.degree. C. within 5 hours.
18. A method of producing the copper alloy for electric and
electronic instruments according to claim 3, comprising the steps
of: conducting a solution heat treatment at a temperature of
850.degree. C. or more for 35 seconds or less, cooling from the
solution heat treatment temperature to 300.degree. C. at a cooling
rate of 50.degree. C./sec or more, and aging at a temperature in
the range from 450 to 600.degree. C. within 5 hours.
19. A method of producing the copper alloy for electric and
electronic instruments according to claim 4, comprising the steps
of: conducting a solution heat treatment at a temperature of
850.degree. C. or more for 35 seconds or less, cooling from the
solution heat treatment temperature to 300.degree. C. at a cooling
rate of 50.degree. C./sec or more, and aging at a temperature in
the range from 450 to 600.degree. C. within 5 hours.
20. A copper alloy for electric and electronic instruments,
comprising Ni of 1 to 3 mass % and Ti of 0.2 to 1.4 mass % with a
ratio (Ni/Ti) of the mass percentage between Ni and Ti in the range
from 2.2 to 4.7, any one or both of Mg and Zr in a total amount of
0.02 to 0.3 mass %, and Zn of 0.1 to 5 mass %, with the balance
being Cu and unavoidable impurities, wherein the copper alloy
contains at least one of an intermetallic compound comprising Ni,
Ti and Mg, an intermetallic compound comprising Ni, Ti and Zr or an
intermetallic compound comprising Ni, Ti, Mg and Zr, and wherein
the copper alloy has a distribution density of the intermetallic
compound in the range from 1.times.10.sup.9 to
1.times.10.sup.13/mm.sup.2, a tensile strength of 650 MPa or more,
an electric conductivity of 55% IACS or more, and a stress
relaxation rate of 20% or less after holding the alloy at
150.degree. C. for 1,000 hours.
21. A copper alloy for electric and electronic instruments,
comprising Ni of 1 to 3 mass % and Ti of 0.2 to 1.4 mass % with a
ratio (Ni/Ti) of the mass percentage between Ni and Ti in the range
from 2.2 to 4.7, any one or both of Mg and Zr in a total amount of
0.02 to 0.3 mass %, Zn of 0.1 to 5 mass %, and Sn in the range of
more than 0 mass % but 0.5 mass % or less, with the balance being
Cu and unavoidable impurities, wherein the copper alloy contains at
least one of an intermetallic compound comprising Ni, Ti and Mg, an
intermetallic compound comprising Ni, Ti and Zr or an intermetallic
compound comprising Ni, Ti, Mg and Zr, and wherein the copper alloy
has a distribution density of the intermetallic compound in the
range from 1.times.10.sup.9 to 1.times.10.sup.13/mm.sup.2, a
tensile strength of 650 MPa or more, an electric conductivity of
55% IACS or more, and a stress relaxation rate of 20% or less after
holding the alloy at 150.degree. C. for 1,000 hours.
22. A copper alloy for electric and electronic instruments,
comprising Ni of 1 to 3 mass % and Ti of 0.2 to 1.4 mass % with a
ratio (Ni/Ti) of the mass percentage between Ni and Ti in the range
from 2.2 to 4.7, Mg of 0.02 to 0.3 mass %, Zn of 0.1 to 5 mass %,
and any one or at least two of Zr, Hf, In and Ag in a total amount
of more than 0 mass % but 1.0 mass % or less, with the balance
being Cu and unavoidable impurities, wherein the copper alloy
contains at least one of an intermetallic compound comprising Ni,
Ti and Mg, an intermetallic compound comprising Ni, Ti and Zr, or
an intermetallic compound comprising Ni, Ti, Mg and Zr, and wherein
the copper alloy has a distribution density of the intermetallic
compound in the range from 1.times.10.sup.9 to
1.times.10.sup.13/mm.sup.2, a tensile strength of 650 MPa or more,
an electric conductivity of 55% IACS or more, and a stress
relaxation rate of 20% or less after holding the alloy at
150.degree. C. for 1,000 hours.
23. A copper alloy for electric and electronic instruments,
comprising Ni of 1 to 3 mass % and Ti of 0.2 to 1.4 mass % with a
ratio (Ni/Ti) of the mass percentage between Ni and Ti in the range
from 2.2 to 4.7, Mg of 0.02 to 0.3 mass %, Zn of 0.1 to 5 mass %,
Sn in the range of more than 0 mass % but 0.5 mass % or less, and
any one or at least two of Zr, Hf, In and Ag in a total amount of
more than 0 mass % but 1.0 mass % or less, with the balance being
Cu and unavoidable impurities, wherein the copper alloy contains at
least one of an intermetallic compound comprising Ni, Ti and Mg, an
intermetallic compound comprising Ni, Ti and Zr, or an
intermetallic compound comprising Ni, Ti, Mg and Zr, and wherein
the copper alloy has a distribution density of the intermetallic
compound in the range from 1.times.10.sup.9 to
1.times.10.sup.13/mm.sup.2, a tensile strength of 650 MPa or more,
an electric conductivity of 55% IACS or more, and a stress
relaxation rate of 20% or less after holding the alloy at
150.degree. C. for 1,000 hours.
24. A method of producing the copper alloy for electric and
electronic instruments according to claim 20, which comprises
applying once or at least twice of heat treatment for precipitation
by aging at a temperature of from 450 to 650.degree. C. within 5
hours, wherein an electric conductivity before the heat treatment
for precipitation by aging is 35% IACS or less.
25. A method of producing the copper alloy for electric and
electronic instruments according to claim 21, which comprises
applying once or at least twice of heat treatment for precipitation
by aging at a temperature of from 450 to 650.degree. C. within 5
hours, wherein an electric conductivity before the heat treatment
for precipitation by aging is 35% IACS or less.
26. A method of producing the copper alloy for electric and
electronic instruments according to claim 22, which comprises
applying once or at least twice of heat treatment for precipitation
by aging at a temperature of from 450 to 650.degree. C. within 5
hours, wherein an electric conductivity before the heat treatment
for precipitation by aging is 35% IACS or less.
27. A method of producing the copper alloy for electric and
electronic instruments according to claim 23, which comprises
applying once or at least twice of heat treatment for precipitation
by aging at a temperature of from 450 to 650.degree. C. within 5
hours, wherein an electric conductivity before the heat treatment
for precipitation by aging is 35% IACS or less.
Description
TECHNICAL FIELD
[0001] The present invention relates to a copper alloy for electric
and electronic instruments improved in its properties.
BACKGROUND ART
[0002] Heretofore, generally, in addition to a stainless-based
steel, copper-based materials such as phosphor bronze, red brass,
and brass, which are excellent in electrical conductivity and
thermal conductivity, have been used widely as materials for parts
of electric and electronic instruments (electrical and electronic
machinery and tools).
[0003] A demand for small size and light weight of the electric and
electronic instruments, accompanied with high density mounting
requirement thereof, has been increased in recent years. When the
electric and electronic instruments are made further small-sized, a
contact area and the thickness of the plate used are reduced.
Accordingly materials having higher strength are required for
maintaining reliability of the instruments equivalent to those of
conventional ones. Connectors fit (contact) to one another by a
given magnitude of contact pressure generated by deflection, (that
is, deformation) of the materials to allow an electric current or
information signals flow or exchange through the joint.
Accordingly, it is a fatal defect that the fitting (joining) force
is decreased as a result of decrease of the contact pressure during
the use, and accordingly the connectors are unable to flow or
exchange the electric current or information signals through the
joint. This decrease of fitting (joining) forces is referred to as
stress relaxation characteristic (creep resistance), and copper
alloys free from deterioration of the stress relaxation
characteristic, that is, copper alloys having an excellent stress
relaxation resistance, are desired for the materials to be used for
these electronic parts.
[0004] Some of the connectors may be connected to heat-generating
instruments, such as CPU (Central Processing Unit) of a personal
computer. The connector material is required to be able to promptly
dissipate the heat in this case, since the fitting (joining) force
is rapidly decreased by acceleration of the stress relaxation due
to heating of the connector material. The material is required to
have a higher electric conductivity because the heat-dissipating
property is ascribed to the electric conductivity of the material.
The higher electric conductivity of the material is also required
from the view point of exchange of information using high frequency
in the future.
[0005] The material is also required to have a good bending
property for making the electric or electronic instruments small
size. Thinning the instruments is one of the strategies for making
the instruments compact, and to reduce the height of the connector
(to make the connector low in the height) is accompanied by
thinning the instruments. Consequently, a connector material having
better workability is desired.
[0006] The material is desired to have high strength with good
electric conductivity while it is excellent in stress relaxation
resistance property and bending property by the reasons as
described above. Specifically, a material having a strength of 600
MPa or more, an electric conductivity of, preferably, 50% IACS or
more, a stress relaxation rate of 20% or less after allowing to
stand at 150.degree. C. for 1,000 hours, and the ratio R/t, which
is an index of bending property, of 1 or less is desired. Also, a
material having a strength of 650 MPa or more and an electric
conductivity of 55% IACS or more is demanded.
[0007] Examples of a usual method of enhancing the strength of the
metallic material include a work reinforcement method, in which a
working strain is introduced into the material, a solid solution
reinforcement method, in which other elements are allowed to be in
the solid solution, and a precipitation reinforcement method, in
which a second phase is precipitated to harden the material.
[0008] Examples of the alloys prepared by the precipitation
reinforcement method include a Cu--Be alloy (C17200), a Cu--Ni--Si
alloy (C70250), a Cu--Fe alloy (C19400) and a Cu--Cr alloy
(C18040). However, while C17200 alloy has a strength of 1,000 MPa
or more and stress relaxation rate of 20% or less with good bending
property by applying a reinforcement mechanism for allowing Be to
precipitate in the Cu host matrix, the electric conductivity is as
low as about 25% IACS. In addition, the use of beryllium (Be) may
actually cause an environmental problem.
[0009] Although the C70250 alloy prepared by allowing an
intermetallic compound comprising Ni--Si to precipitate in the Cu
host matrix has a strength of 600 MPa or more and a stress
relaxation rate of 20% or less with good bending property, it
cannot give an electric conductivity of 50% IACS or more.
[0010] Although the C19400 alloy has a strength of 600 MPa or more
and an electric conductivity of about 65% IACS by applying a
reinforcement mechanism for allowing iron (Fe) to precipitate in
the Cu host matrix, the desired properties for the stress
relaxation rate and bending property are not satisfied in the
C19400 alloy.
[0011] The desired properties for the stress relaxation rate and
the bending property are not satisfied either in the C18040 alloy
as in the C19400 alloy, although the alloy has an electric
conductivity of about 80% IACS and a strength of about 600 MPa.
[0012] No materials satisfying the desired properties can be
obtained using any of the precipitation reinforcement methods as
described above, and developments of novel materials are strongly
required.
[0013] On the other hand, the strength and the electric
conductivity have been improved in some copper alloys for the
electronic instruments by allowing a Ni--Ti intermetallic compound
to uniformly and finely precipitate in the Cu matrix.
[0014] In another example, adhesiveness between a lead frame and a
resin has been improved by adding aluminum (Al), silicon (Si),
manganese (Mn) or magnesium (Mg) to a Cu--Ni--Ti alloy.
[0015] However, the desired properties for the copper alloy in
accordance with the improvement of performance of recently
developed electronic instruments cannot be satisfied even by using
these copper alloys, since the desired strength, electric
conductivity and bending property as well as stress relaxation
resistance, cannot be simultaneously satisfied.
[0016] Further, in some examples, various properties of the copper
alloy have been improved by allowing a Ni--Ti intermetallic
compound to precipitate in copper.
[0017] Other and further features and advantages of the invention
will appear more fully from the following description,
appropriately referring to the accompanying drawings.
BRIEF DESCRIPTION OF DRAWINGS
[0018] FIG. 1 is a schematic explanatory view for illustrating a
test method of stress relaxation property.
[0019] FIG. 2 is a schematic explanatory view for illustrating a
test method of solder adhesiveness.
DISCLOSURE OF INVENTION
[0020] According to the present invention, there is provided the
following means:
(1) A copper alloy for electric and electronic instruments,
comprising Ni of 1 to 3 mass %, Ti of 0.2 to 1.2 mass %, any one or
both of Mg and Zr of 0.02 to 0.2 mass %, and Zn of 0.1 to 1 mass %,
with the balance being Cu and unavoidable impurities,
[0021] wherein the copper alloy contains at least one of an
intermetallic compound comprising Ni, Ti and Mg, an intermetallic
compound comprising Ni, Ti and Zr, or an intermetallic compound
comprising Ni, Ti, Mg and Zr, and wherein the copper alloy has a
stress relaxation rate of 20% or less after holding the alloy at
150.degree. C. for 1,000 hours;
(2) The copper alloy for electric and electronic instruments
according to the above item (1),
[0022] wherein the intermetallic compound comprising Ni, Ti and Mg,
the intermetallic compound comprising Ni, Ti and Zr, or the
intermetallic compound comprising Ni, Ti, Mg and Zr has an average
particle diameter in the range from 5 to 100 nm and a distribution
density of from 1.times.10.sup.10 to 1.times.10.sup.13/mm.sup.2,
and
wherein the crystal grain size of a host matrix of the alloy is 10
.mu.m or less;
(3) A copper alloy for electric and electronic instruments,
comprising Ni of 1 to 3 mass %, Ti of 0.2 to 1.2 mass %, any one or
both of Sn and Si of 0.02 to 0.2 mass %, and Zn of 0.1 to 1 mass %,
with the balance being Cu and unavoidable impurities,
wherein the copper alloy contains at least one of an intermetallic
compound comprising Ni, Ti and Sn, an intermetallic compound
comprising Ni, Ti and Si, or an intermetallic compound comprising
Ni, Ti, Sn and Si, and
wherein the copper alloy has a stress relaxation rate of 20% or
less after holding the alloy at 150.degree. C. for 1,000 hours;
(4) The copper alloy for electric and electronic instruments
according to the above item (3),
[0023] wherein the intermetallic compound comprising Ni, Ti and Sn,
the intermetallic compound comprising Ni, Ti and Si, or the
intermetallic compound comprising Ni, Ti, Sn and Si has an average
particle diameter in the range from 5 to 100 nm and a distribution
density of from 1.times.10.sup.10 to 1.times.10.sup.13/mm.sup.2,
and
wherein the crystal grain size of a host matrix of the alloy is 10
.mu.m or less;
(5) A method of producing the copper alloy for electric and
electronic instruments according to any one of the above items (1)
to (4), comprising the steps of:
[0024] conducting a solution heat treatment at a temperature of
850.degree. C. or more for 35 seconds or less,
[0025] cooling from the solution heat treatment temperature to
300.degree. C. at a cooling rate of 50.degree. C./sec or more,
[0026] cold-rolling at a cold rolling ratio in the range of more
than 0% but 50% or less, and
[0027] aging at a temperature in the range from 450 to 600.degree.
C. within 5 hours;
(6) A method of producing the copper alloy for electric and
electronic instruments according to any one of the above items (1)
to (4), comprising the steps of:
[0028] conducting a solution heat treatment at a temperature of
850.degree. C. or more for 35 seconds or less,
[0029] cooling from the solution heat treatment temperature to
300.degree. C. at a cooling rate of 50.degree. C./sec or more,
and
[0030] aging at a temperature in the range from 450 to 600.degree.
C. within 5 hours;
[0031] (7) A copper alloy for electric and electronic instruments,
comprising Ni of 1 to 3 mass % and Ti of 0.2 to 1.4 mass % with a
ratio (Ni/Ti) of the mass percentage between Ni and Ti in the range
from 2.2 to 4.7, any one or both of Mg and Zr in a total amount of
0.02 to 0.3 mass %, and Zn of 0.1 to 5 mass %, with the balance
being Cu and unavoidable impurities,
wherein the copper alloy contains at least one of an intermetallic
compound comprising Ni, Ti and Mg, an intermetallic compound
comprising Ni, Ti and Zr or an intermetallic compound comprising
Ni, Ti, Mg and Zr, and
[0032] wherein the copper alloy has a distribution density of the
intermetallic compound in the range from 1.times.10.sup.9 to
1.times.10.sup.13/mm.sup.2, a tensile strength of 650 MPa or more,
an electric conductivity of 55% IACS or more, and a stress
relaxation rate of 20% or less after holding the alloy at
150.degree. C. for 1,000 hours;
[0033] (8) A copper alloy for electric and electronic instruments,
comprising Ni of 1 to 3 mass % and Ti of 0.2 to 1.4 mass % with a
ratio (Ni/Ti) of the mass percentage between Ni and Ti in the range
from 2.2 to 4.7, any one or both of Mg and Zr in a total amount of
0.02 to 0.3 mass %, Zn of 0.1 to 5 mass %, and Sn in the range of
more than 0 mass % but 0.5 mass % or less, with the balance being
Cu and unavoidable impurities,
wherein the copper alloy contains at least one of an intermetallic
compound comprising Ni, Ti and Mg, an intermetallic compound
comprising Ni, Ti and Zr or an intermetallic compound comprising
Ni, Ti, Mg and Zr, and
[0034] wherein the copper alloy has a distribution density of the
intermetallic compound in the range from 1.times.10.sup.9 to
1.times.10.sup.13/mm.sup.2, a tensile strength of 650 MPa or more,
an electric conductivity of 55% IACS or more, and a stress
relaxation rate of 20% or less after holding the alloy at
150.degree. C. for 1,000 hours;
[0035] (9) A copper alloy for electric and electronic instruments,
comprising Ni of 1 to 3 mass % and Ti of 0.2 to 1.4 mass % with a
ratio (Ni/Ti) of the mass percentage between Ni and Ti in the range
from 2.2 to 4.7, Mg of 0.02 to 0.3 mass %, Zn of 0.1 to 5 mass %,
and any one or at least two of Zr, Hf, In and Ag in a total amount
of more than 0 mass % but 1.0 mass % or less, with the balance
being Cu and unavoidable impurities,
wherein the copper alloy contains at least one of an intermetallic
compound comprising Ni, Ti and Mg, an intermetallic compound
comprising Ni, Ti and Zr, or an intermetallic compound comprising
Ni, Ti, Mg and Zr, and
[0036] wherein the copper alloy has a distribution density of the
intermetallic compound in the range from 1.times.10.sup.9 to
1.times.10.sup.13/mm.sup.2, a tensile strength of 650 MPa or more,
an electric conductivity of 55% IACS or more, and a stress
relaxation rate of 20% or less after holding the alloy at
150.degree. C. for 1,000 hours;
[0037] (10) A copper alloy for electric and electronic instruments,
comprising Ni of 1 to 3 mass % and Ti of 0.2 to 1.4 mass % with a
ratio (Ni/Ti) of the mass percentage between Ni and Ti in the range
from 2.2 to 4.7, Mg of 0.02 to 0.3 mass %, Zn of 0.1 to 5 mass %,
Sn in the range of more than 0 mass % but 0.5 mass % or less, and
any one or at least two of Zr, Hf, In and Ag in a total amount of
more than 0 mass % but 1.0 mass % or less, with the balance being
Cu and unavoidable impurities,
wherein the copper alloy contains at least one of an intermetallic
compound comprising Ni, Ti and Mg, an intermetallic compound
comprising Ni, Ti and Zr, or an intermetallic compound comprising
Ni, Ti, Mg and Zr, and
[0038] wherein the copper alloy has a distribution density of the
intermetallic compound in the range from 1.times.10.sup.9 to
1.times.10.sup.13/mm.sup.2, a tensile strength of 650 MPa or more,
an electric conductivity of 55% IACS or more, and a stress
relaxation rate of 20% or less after holding the alloy at
150.degree. C. for 1,000 hours; and
[0039] (11) A method of producing the copper alloy for electric and
electronic instruments according to any one of the above items (7)
to (10), which comprises applying once or at least twice of heat
treatment for precipitation by aging at a temperature of from 450
to 650.degree. C. within 5 hours,
wherein an electric conductivity before the heat treatment for
precipitation by aging is 35% IACS or less.
[0040] Hereinafter, a first embodiment of the present invention
means to include the copper alloys for electric and electronic
instruments described in the items (1) to (4) above and the methods
of producing the copper alloy for electric and electronic
instruments described in the items (5) to (6) above.
[0041] A second embodiment of the present invention means to
include the copper alloys for electric and electronic instruments
described in the items (7) to (10) above and the method of
producing the copper alloy for electric and electronic instruments
described in the item (11) above.
[0042] Herein, the present invention means to include both of the
above first and second embodiments, unless otherwise specified.
BEST MODE FOR CARRYING OUT THE INVENTION
[0043] The present invention is explained in detail below.
[0044] In the course of studies for strengthening the copper alloy
with an intermetallic compound comprising nickel (Ni) and titanium
(Ti) by a precipitation reinforcement method in which a second
phase is precipitated, the present inventors have found that a
material capable of substantially satisfying the desired properties
such as the strength, electric conductivity, bending property,
stress relaxation resistance and solder adhesiveness can be
produced by modifying the intermetallic compound by adding
magnesium (Mg), zirconium (Zr), tin (Sn), silicon (Si) or the
like.
[0045] The electric and electronic instruments of the present
invention, particularly of the first embodiment of the present
invention, include instruments mounted for a car.
[0046] The first embodiment of the present invention will be
described below.
[0047] Various properties of an alloy are remarkably improved in
the present invention, particularly in the first embodiment of the
present invention, by forming an intermetallic compound comprising
Ni, Ti and Mg (referred to as "Ni--Ti--Mg" hereinafter), an
intermetallic compound comprising Ni, Ti and Zr (referred to as
"Ni--Ti--Zr" hereinafter), or an intermetallic compound comprising
Ni, Ti, Mg and Zr (referred to as "Ni--Ti--Mg--Zr" hereinafter)
precipitated in the Cu host matrix. These intermetallic compounds
are utterly different from Ni--Ti precipitates formed in
conventional alloys, and provide quite high strength, electric
conductivity and stress relaxation resistance property.
[0048] As described above, the strength is improved by
precipitation strengthening mechanism while the electric
conductivity increases, when the Ni--Ti is finely dispersed in the
Cu host matrix. However, the magnitude of reinforcement becomes
quite large, as compared with precipitation of the Ni--Ti, by
allowing the Ni--Ti--Mg, the Ni--Ti--Zr or the Ni--Ti--Mg--Zr to
finely disperse individually or compositely in the Cu host matrix.
This effect permits materials having excellent strength and
electric conductivity to be obtained. This effect is exhibited even
when the Ni--Ti is simultaneously dispersed, and the magnitude of
reinforcement is larger as the dispersion density of the
Ni--Ti--Mg, the Ni--Ti--Zr or the Ni--Ti--Mg--Zr is higher. In this
case, the amount of the dispersion density of the Ni--Ti--Mg, the
Ni--Ti--Zr or the Ni--Ti--Mg--Zr is desirably equal to or more than
that of the Ni--Ti.
[0049] The same effect as described above could be also observed
when an intermetallic compound comprising Ni, Ti and Sn (referred
to as "Ni--Ti--Si" hereinafter), an intermetallic compound
comprising Ni, Ti and Si (referred to as "Ni--Ti--Si" hereinafter)
or an intermetallic compound comprising Ni, Ti, Sn and Si (referred
to as "Ni--Ti--Sn--Si" hereinafter) had been precipitated.
[0050] Next, the stress relaxation property will be described
below. The stress relaxation resistance property is remarkably
improved when the Ni--Ti--Mg, the Ni--Ti--Zr or the Ni--Ti--Mg--Zr
is finely, and individually or compositely, dispersed in the Cu
host matrix, as compared with the case when the Ni--Ti is finely
dispersed in the host matrix. On the contrary, a stress relaxation
rate of 20% or less cannot be achieved when only the Ni--Ti is
precipitated.
[0051] This may be interpreted that, since the Ni--Ti--Mg, the
Ni--Ti--Zr or the Ni--Ti--Mg--Zr has a different crystal structure
from that of the Ni--Ti compound, the stress relaxation resistance
property is remarkably improved by finely dispersing such
intermetallic compound having the different crystal structure in
the Cu host matrix.
[0052] Stress relaxation is a phenomenon by which the strain is
released by allowing dislocations in the metal to move. Since the
Ni--Ti--Mg, the Ni--Ti--Zr or the Ni--Ti--Mg--Zr has a larger force
for fixing the dislocations than the Ni--Ti compound, the stress is
hardly relaxed in the alloy containing the former intermetallic
compound.
[0053] The same phenomenon is confirmed in the alloy containing the
Ni--Ti--Sn, the Ni--Ti--Si or the Ni--Ti--Sn--Si. A material being
excellent in the stress relaxation resistance property and having
the desired properties can be produced by forming these
precipitates in the alloy.
[0054] The desired properties can be obtained by prescribing the
amount of components as described below.
[0055] The content of Ni is limited in the range from 1 to 3 mass
%, because a sufficient strength cannot be obtained due to a small
amount of reinforcement by precipitation when the content of Ni is
too small, and the stress relaxation resistance property cannot be
improved. On the other hand, a too large amount of Ni causes a
decrease of the electric conductivity even after the aging
treatment because an excess amount of Ni is solute in the host
matrix. In addition, the alloy cannot be produced by an
industrially stable process since the temperature for the solution
heat treatment (solid solution treatment) comes to near the melting
temperature. Further, it is another problem that the bending
property becomes poor due to coarsening of crystal grains since a
long time of the solution heat treatment at a higher temperature is
necessary. The content of Ni is preferably in the range from 1.4 to
2.6 mass %, and more preferably in the range from 1.8 to 2.3 mass
%.
[0056] The content of Ti is limited in the range from 0.2 to 1.2
mass % because, when the content of Ti is too small, a sufficient
strength cannot be obtained due to a small amount of reinforcement
by precipitation, and the stress relaxation resistance property
cannot be improved. On the other hand, a too large amount of Ti
causes a decrease of the electric conductivity even after the aging
treatment because an excess amount of Ti is solute in the host
matrix. In addition, it is another problem that the bending
property becomes poor due to coarsening of crystal grains since a
long time of the solution heat treatment at a higher temperature is
necessary. The content of Ti is preferably in the range from 0.5 to
1.1 mass %, more preferably in the range from 0.7 to 1.0 mass
%.
[0057] Mg forms an intermetallic compound (also referred to as a
"precipitate" hereinafter) together with Ni, Ti, Zr and the like,
and improves the strength, electric conductivity, bending property,
stress relaxation resistance property, and the like. The content of
Mg is limited in the range from 0.02 to 0.2 mass % because, when
the content of Mg is too small, the stress relaxation rate becomes
poor due to a small amount of the precipitate comprising Ni, Ti and
Mg or the like. On the other hand, the bending property becomes
poor due to coarsening of crystal grains when the amount of Mg is
too large, since a high temperature and long time of the solution
heat treatment is required. In addition, the electric conductivity
is poor even by applying an aging treatment since excess Mg remains
in the solid solution. The stress relaxation rate also becomes poor
probably due to a different proportion of constitution elements in
the precipitate. The content of Mg is preferable in the range from
0.05 to 0.15 mass %, and more preferable in the range from 0.08 to
0.12 mass %.
[0058] The content of Zr is limited in the range from 0.02 to 0.2
mass % by the same reason as limiting the content of Mg. The
content of Zr is preferably in the range from 0.05 to 0.15 mass %,
and more preferably in the range from 0.08 to 0.12 mass %.
[0059] Sn forms a precipitate together with Ni, Ti and Si, and
improves the strength, electric conductivity, bending property,
stress relaxation resistance property, and the like. The content of
Sn is limited in the range from 0.02 to 0.2 mass % because, when
the amount of Sn is too small, the stress relaxation rate becomes
poor due to a too small amount of the precipitate comprising Ni, Ti
and Sn or the like. The electric conductivity and bending property
become poor when the amount of Sn is too large since excess Sn
remains in the solid solution. The stress relaxation rate is also
poor probably due to the effect of a different proportion of
constitution elements in the precipitate. The content of Sn is
preferably in the range from 0.05 to 0.15 mass %, and more
preferably in the range from 0.08 to 0.12 mass %.
[0060] The content of Si is limited in the range from 0.02 to 0.2
mass % because, when the content of Si is too small, the strength
and stress relaxation resistance property become poor due to a
small amount of the precipitate comprising Ni, Ti and Si or the
like, and the electric conductivity becomes poor since excess Ni
remains in the solid solution. The electric conductivity decreases
when the content of Si is too large, since excess Si is solute in
the copper host matrix when a desired precipitate is formed. The
content of Si is preferably in the range from 0.05 to 0.15 mass %,
and more preferably in the range from 0.08 to 0.12 mass %.
[0061] The average particle diameter of the intermetallic compound
is usually in the range from 1 to 100 nm, preferably in the range
from 5 to 100 nm, as a diameter of corresponding spheres having an
equal volume to the volume of the intermetallic compound. A
distribution density in the range from 1.times.10.sup.10 to
1.times.10.sup.13/mm.sup.2 is preferable since the alloy becomes
excellent in the strength and bending property.
[0062] The effect for improving the strength is insufficient when
the average particle diameter of the intermetallic compound is too
small, while the intermetallic compound does not contribute for
improving the strength by precipitation when the average particle
diameter is too large. The average particle diameter is further
preferably in the range from 10 to 60 nm, and more preferably in
the range from 20 to 50 nm. The average particle diameter of the
intermetallic compound is controlled by the heating temperature and
heating time in the aging step. A higher temperature or longer time
gives a larger average particle diameter. On the contrary, a lower
temperature or shorter time gives a smaller average particle
diameter.
[0063] When the distribution density of the intermetallic compound
is too small, the effect for improving the strength by
precipitation becomes insufficient, while coarse precipitates tend
to be formed at grain boundaries to deteriorate the bending
property when the distribution density is too large. The
distribution density is further preferably in the range from
3.times.10.sup.10 to 5.times.10.sup.12/mm.sup.2, more preferably in
the range from 1.times.10.sup.11 to 3.times.10.sup.12/mm.sup.2. The
distribution density of the intermetallic compound is controlled by
appropriately combining the conditions for the heat treatment for
precipitation by aging, cold working that is applied prior to the
heat treatment for precipitation by aging, solution heat treatment
and hot rolling. The distribution density of the precipitates is
calculated as the number of the precipitates per unit area
(number/mm.sup.2) by measuring the number of the precipitates with
a transmission electron microscope observation.
[0064] The crystal grain size of the host matrix is preferably 10
.mu.m or less. The bending property is deteriorated when the
crystal grain size of the host matrix is too large. The preferable
diameter is 5 .mu.m or less. While the lower limit of the crystal
grain size of the host matrix is not particularly restricted, it is
usually 3 .mu.m. The crystal grain size as used herein refers to
the longer diameter of the grains. The crystal grain size of the
host matrix is controlled by the heating temperature and heating
time in the solution heat treatment step. The higher temperature or
longer time gives a larger crystal grain size, while the lower
temperature or shorter time gives a smaller crystal grain size.
[0065] Zn improves adhesiveness of a solder and prevents plating
from being peeled. A preferable use of the present invention is
electronic instruments, and most of parts thereof are joined with a
solder. Accordingly, improved adhesiveness of the solder causes an
improvement of reliability of the parts, which is an essential
property for applying to the electronic instruments. The effect of
Zn has been discussed in recent years (for example, see Sindo
Gijutu Kennkyuukai Shi (Journal of Japan Copper and Brass
Association), Vol. 026 (1987), pp. 51-56). This report describes
that adding Zn improves heat-peeling resistance. The heat-peeling
resistance is considered to be improved by adding Zn, because voids
are suppressed from being generated, and they are suppressed from
being concentrated at the interface between the host material
comprising Ni and Si and diffusion layers. While the example above
is for alloys of precipitation type such as Cu--Ni--Si alloys, the
same effect has been confirmed in the first embodiment of the
present invention.
[0066] The content of Zn is limited in the range form 0.1 to 1 mass
% because, when the content of Zn is too small, the heat-peeling
resistance property is not exhibited, while the electric
conductivity is reduced when the content of Zn is too large. The
content of Zn is preferably in the range from 0.2 to 0.8 mass %,
more preferably in the range from 0.35 to 0.65 mass %.
[0067] The stress relaxation rate of the copper alloy for electric
and electronic instruments according to the present invention,
particularly according to the first embodiment of the present
invention, is 20% or less when the alloy is held at 150.degree. C.
for 1,000 hours. The rate is preferably 18% or less, and more
preferably 16% or less; and although the lower limit is not
particularly restricted, it is 10%.
[0068] The copper alloy according to the present invention,
particularly according to the first embodiment of the present
invention, is produced through the steps comprising, for example,
hot rolling, cold rolling, solution heat treatment and aging
treatment, and if necessary finish cold rolling and stress-relief
annealing. The intermetallic compound may be adjusted within the
range of the present invention by controlling the conditions, such
as the solution heat treatment (temperature) and cooling rate in
the subsequent cooling step, in the production process. The hot
rolling temperature may be, for example, in the range from 850 to
1,000.degree. C., and the subsequent cold rolling may be conducted
at the processing ratio of, for example, 90% or more.
[0069] An embodiment of the production method according to the
present invention, particularly according to the first embodiment
of the present invention, comprises the steps of: conducting a
solution heat treatment at 850.degree. C. or more within 35
seconds, cooling from the solution heat treatment temperature to
300.degree. C. at a cooling rate of 50.degree. C./sec or more,
cold-rolling at a rolling ratio in the range of more than 0% but
50% or less, and aging at a temperature in the range from 450 to
600.degree. C. within 5 hours. Another embodiment of the production
method according to the present invention, particularly according
to the first embodiment of the present invention, comprises the
steps of: conducting a solution heat treatment at 850.degree. C. or
more within 35 seconds, cooling from the solution heat treatment
temperature to 300.degree. C. at a cooling rate of 50.degree.
C./sec or more, and aging at a temperature from 450 to 600.degree.
C. within 5 hours. The finish cold rolling ratio thereafter is
preferably 30% or less.
[0070] The solution heat treatment is preferably conducted at
850.degree. C. or more within 35 seconds in the present invention,
particularly in the first embodiment of the present invention.
Recrystallization does not occur when the solution heat treatment
temperature is too low, resulting in remarkably deterioration in
bending property. Further, solid solutions are not formed even by
recrystallization to make it impossible to attain the highest
precipitation reinforcement in the subsequent aging step due to the
presence of crystallized grains, coarse precipitates or the like.
Furthermore, deterioration of the bending property is also
apprehended due to the presence of residual crystals, precipitates
or the like. The alloy is preferably cooled to 300.degree. C. at a
cooling rate of 50.degree. C./sec or more after the solution heat
treatment, because when the cooling rate is too small, the elements
once incorporated into the solid solution are precipitated. Such
precipitates do not contribute to strengthening due to their
coarsening.
[0071] The upper limit of the solution heat treatment temperature
is preferably 1,000.degree. C. or less from the view point of fuel
cost. Too long solution heat treatment time causes deterioration of
the bending property due to coarsening of crystal grains. The
solution heat treatment time is preferably within 25 seconds.
[0072] It is preferably that the cold rolling after the solution
heat treatment is not conducted, or is conducted at a cold rolling
ratio of 50% or less. The higher cold rolling ratio causes
deterioration of the bending property. The ratio is more preferably
30% or less.
[0073] The aging treatment is preferably conducted at a temperature
from 450 to 600.degree. C. within 5 hours. Too low aging treatment
temperature results in insufficient strength due to an insufficient
amount of precipitates, while too high aging treatment temperature
does not contribute to the strength since the precipitates get
coarse. The aging treatment temperature is preferably in the range
from 480 to 560.degree. C.
[0074] The direction of final plastic working as used in the
present invention, in particular in the first embodiment of the
present invention, refers to the direction of rolling when the
rolling is the finally carried out plastic working, or to the
direction of drawing when the drawing (linear drawing) is the
plastic working finally carried out. The plastic working refers to
workings such as rolling and drawing, but working for the purpose
of leveling (vertical leveling) using, for example, a tension
leveler, is not included in this plastic working.
[0075] Next, the second embodiment of the present invention will be
described below.
[0076] Various properties of the alloy are remarkably improved in
the present invention, particularly in the second embodiment of the
present invention, by forming an intermetallic compound comprising
Ni, Ti and Mg (referred to as "Ni--Ti--Mg" hereinafter), an
intermetallic compound comprising Ni, Ti and Zr (referred to as
"Ni--Ti--Zr" hereinafter), or an intermetallic compound comprising
Ni, Ti, Mg and Zr (referred to as "Ni--Ti--Mg--Zr" hereinafter)
precipitated in the Cu host matrix. These intermetallic compounds
are utterly different from Ni--Ti precipitates formed in
conventional alloys, and provide quite high strength, electric
conductivity and stress relaxation resistance property.
[0077] As described above, the strength is improved by
precipitation strengthening mechanism while the electric
conductivity increases, when the Ni--Ti is finely dispersed in the
Cu host matrix. However, the magnitude of reinforcement becomes
quite large, as compared with precipitation of the Ni--Ti, by
allowing the Ni--Ti--Mg, the Ni--Ti--Zr or the Ni--Ti--Mg--Zr to
finely disperse individually or compositely in the Cu host matrix.
This effect permits materials having excellent strength and
electric conductivity to be obtained. This effect is exhibited even
when the Ni--Ti is simultaneously dispersed, and the magnitude of
reinforcement is larger as the dispersion density of the
Ni--Ti--Mg, the Ni--Ti--Zr or the Ni--Ti--Mg--Zr is higher. In this
case, the amount of the dispersion density of the Ni--Ti--Mg, the
Ni--Ti--Zr or the Ni--Ti--Mg--Zr is desirably equal to or more than
that of the Ni--Ti. These Ni--Ti base ternary or multi-component
compounds can contribute to the improvement of the stress
relaxation resistance property.
[0078] Both the strength and stress relaxation resistance property
may be improved, without reducing the electric conductivity, by
allowing appropriate amounts of Mg or Sn to be in the solid
solution.
[0079] The desired properties may be obtained by prescribing the
amount of components as described below.
[0080] The content of Ni is limited in the range from 1 to 3 mass
%, because a sufficient strength cannot be obtained due to a small
amount of reinforcement by precipitation when the content of Ni is
too small, and the stress relaxation resistance property cannot be
improved. On the other hand, a too large amount of Ni causes a
decrease of the electric conductivity even after the aging
treatment because an excess amount of Ni is solute in the host
matrix. In addition, the alloy cannot be produced by an
industrially stable process since the temperature for the solution
heat treatment comes to near the melting temperature. Further, it
is another problem that the bending property becomes poor due to
coarsening of crystal grains since a long time of the solution heat
treatment at a higher temperature is necessary. The content of Ni
is preferably in the range from 1.2 to 2.4 mass %, and more
preferably in the range from 1.4 to 2.2 mass %.
[0081] The content of Ti is limited in the range from 0.2 to 1.4
mass % because, when the content of Ti is too small, a sufficient
strength cannot be obtained due to a small amount of reinforcement
by precipitation, and the stress relaxation resistance property
cannot be improved. On the other hand, a too large amount of Ti
causes a decrease of the electric conductivity even after the aging
treatment because an excess amount of Ti is solute in the host
matrix. In addition, it is another problem that the bending
property becomes poor due to coarsening of crystal grains since a
long time of the solution heat treatment at a higher temperature is
necessary. The content of Ti is preferably in the range from 0.3 to
1.0 mass %, more preferably in the range from 0.35 to 0.9 mass
%.
[0082] The ratio (Ni/Ti) in the mass percentage between Ni and Ti
is limited in the range form 2.2 to 4.7 because both elements
should be blended in an appropriate ratio in order to allow the
multi-component compounds, such as Ni--Ti base or Ni--Ti--Mg base
compounds, to be precipitated as a compound having a stoichiometric
composition in Cu. The ratio out of this range is not preferable
since the solute elements do not contribute to the formation of the
compound and they reduce the electric conductivity by being in the
solid solution. The ratio (Ni/Ti) is preferable in the range from
2.6 to 3.8, more preferably in the range form 2.8 to 3.6.
[0083] Mg forms an intermetallic compound (also referred to as a
"precipitate" hereinafter) together with Ni, Ti and Zr, and
improves the strength, electric conductivity, bending property,
stress relaxation resistance property, and the like. The content of
either or both of Mg and Zr in total is limited in the range from
0.02 to 0.3 mass % because, when the content is too small, the
strength becomes poor since the amount of the precipitate
comprising Ni, Ti and Mg, the precipitate comprising Ni, Ti and Zr
and/or the precipitate comprising Ni, Ti, Mg and Zr is small. When
the content is too large, on the other hand, a high temperature and
a long time is necessary for the solution heat treatment, and
crystal grains get coarse to deteriorate the bending property. In
addition, excess Mg and/or Zr remains in the solid solution even by
conducting an aging treatment, and the electric conductivity is
poor. The content of either or both of Mg and Zr in total is
preferably in the range from 0.05 to 0.18 mass %, and more
preferably in the range from 0.08 to 0.15 mass %.
[0084] The distribution density of the intermetallic compound in
the range from 1.times.10.sup.9 to 1.times.10.sup.13/mm.sup.2 is
preferable because the ratio gives excellent strength and bending
property.
[0085] When the distribution density of the intermetallic compound
is too small, the effect for improving the strength by
precipitation becomes insufficient, while coarse precipitates tend
to be formed at grain boundaries to deteriorate the bending
property when the distribution density is too large. The
distribution density is further preferably in the range from
3.times.10.sup.10 to 5.times.10.sup.12/mm.sup.2, more preferably in
the range from 1.times.10.sup.11 to 3.times.10.sup.12/mm.sup.2. The
distribution density of the intermetallic compound is controlled by
appropriately combining the conditions for the heat treatment for
precipitation by aging, cold working that is applied prior to the
heat treatment for precipitation by aging, solution heat treatment
and hot rolling.
[0086] The distribution density of the precipitates is calculated
as the number of the precipitates per unit area (number/mm.sup.2)
by measuring the number of the precipitates with a transmission
electron microscope observation.
[0087] Zn improves adhesiveness of a solder and prevents plating
from being peeled. A preferable use of the present invention is
electronic instruments, and most of parts thereof are joined with a
solder. Accordingly, improved adhesiveness of the solder causes an
improvement of reliability of the parts, which is an essential
property for applying to the electronic instruments. The effect of
Zn has been discussed in recent years (for example, see Sindo
Gijutu Kennkyuukai Shi (Journal of Japan Copper and Brass
Association), Vol. 026 (1987), pp. 51-56). This report describes
that adding Zn improves heat-peeling resistance. The heat-peeling
resistance is considered to be improved by adding Zn, because voids
are suppressed from being generated, and they are suppressed from
being concentrated at the interface between the host material
comprising Ni and Si and diffusion layers. While the example above
is for alloys of precipitation type such as Cu--Ni--Si alloys, the
same effect has been confirmed in the second embodiment of the
present invention.
[0088] The content of Zn is limited in the range form 0.1 to 5 mass
% because, when the content of Zn is too small, the heat-peeling
resistance property is not exhibited, while the electric
conductivity is reduced when the content of Zn is too large. The
content of Zn is preferably in the range from 0.2 to 3.0 mass %,
more preferably in the range from 0.3 to 1 mass %.
[0089] Sn is solute in the solid solution with Mg and serves for
improving the stress relaxation resistance property. The element is
effective for suppressing coarse Ni--Ti from precipitating in the
cooling step of the solution heat treatment and the hot rolling
conducted at a temperature of 900.degree. C. or more, and resulting
in improving the strength by enhancing the magnitude of
precipitation hardening. Since the alloy system of the present
invention permits an ideal solid solution state, in which almost
all atoms are in the solid solution, to be formed at a temperature
as high as 900.degree. C. or more, it is important for attaining
good precipitation reinforcement to prevent coarse compounds from
precipitating at a high temperature where atomic diffusion is
rapid. This state is favorably realized by adding Sn, and the
strength and stress relaxation resistance property are improved by
aging precipitation. Further, Sn can prevent coarse compounds from
precipitating at grain boundaries, to improve the bending property.
While the effect is enhanced as the content of Sn is larger, the
electric conductivity becomes poor when the content of Sn is too
large since excess Sn remains in the solid solution. The content of
Sn is generally in the range of more than 0 mass % but 0.5 mass %
or less, preferably in the range from 0.05 to 0.25 mass %.
[0090] Zr, Hf, In and Ag improve the strength, electric
conductivity, stress relaxation resistance property, and the like
by forming precipitates together with Ni and Ti. While the effect
is enhanced as the contents of these elements are higher, the
bending property is deteriorated due to coarsening of crystal
grains when the contents exceed 1.0 mass % since the solution heat
treatment at a high temperature for a long time is necessary. In
addition, the electric conductivity is also deteriorated since
excess atoms remain in the solid solution even by conducting an
aging treatment. The total content of Zr, Hf, In and Ag is in the
range of more than 0 mass % but 1.0 mass % or less, preferably in
the range from 0.05 to 0.5 mass %, and more preferably in the range
from 0.07 to 0.3 mass %.
[0091] The tensile strength of the copper alloy for the electric
and electronic instruments of the present invention, particularly
of the second embodiment of the present invention, is 650 MPa or
more. The tensile strength is preferably 750 MPa or more. Although
the upper limit is not particularly restricted, it is generally 850
MPa.
[0092] The electric conductivity of the copper alloy for the
electric and electronic instruments of the present invention,
particularly of the second embodiment of the present invention, is
55% IACS or more. The electric conductivity is preferably 60% IACS
or more. Although the upper limit is not particularly restricted,
it is generally 70% IACS.
[0093] The stress relaxation rate of the copper alloy for electric
and electronic instruments according to the present invention,
particularly according to the second embodiment of the present
invention, is 20% or less when the alloy is held at 150.degree. C.
for 1,000 hours. The rate is preferably 18% or less, and more
preferably 16% or less; and although the lower limit is not
particularly restricted, it is 10%.
[0094] The copper alloy according to the present invention,
particularly according to the second embodiment of the present
invention, is produced by the steps of: for example, casting,
homogenization treatment, hot rolling, cold rolling, solution heat
treatment and aging treatment, and, if necessary, finish cold
rolling and stress-relief annealing.
[0095] While the cooling rate is preferably increased for
preventing solute elements from segregating at finally solidified
portions at the time of casting, a too rapid cooling rate may form
cavities in a resulting ingot to deteriorate the quality or to
generate internal defects by enhancing the internal stress of a
resulting ingot. Accordingly, the cooling rate is preferably in the
range of 1 to 100.degree. C./sec, more preferably in the range from
10 to 80.degree. C./sec.
[0096] The alloy is preferably homogenized by annealing at a
temperature above the solution heat temperature in accordance with
the atomic weight of the solute in the alloy in order to form a
solid solution while coarse Ni--Ti base compounds are prevented
from precipitating. Homogenizing annealing at a higher temperature
than necessary is not preferable since oxidation of elements such
as Ti, Mg, Zr and Hf is facilitated to deteriorate such quality as
adhesiveness of plating. Accordingly, the temperature for holding
an ingot before hot rolling is usually in the range from 800 to
1,050.degree. C., preferably from 900 to 1,000.degree. C., and more
preferably from 960 to 1,000.degree. C. The holding time is
preferably in the range from 1 hour or more to 10 hours or less in
order to make the elements to be solute sufficiently in the solid
solution and prevent oxidization. The heating rate is preferably
3.degree. C./min or more, since coarse precipitates are formed when
the heating rate to the holding temperature is slow.
[0097] The cooling rate is usually increased by showering cold
water at a temperature of 20.degree. C. or lower or other methods
in order to suppress solute atoms from precipitating in the cooling
step during the time from the start to the end of the hot rolling.
The cooling rate is preferably in the range from 5 to 300.degree.
C./sec, more preferably 50 to 300.degree. C./sec.
[0098] Excellent strength, electric conductivity, stress relaxation
resistance property and bending property may be obtained by
conducting a heat treatment(s) for precipitation by aging once or
twice at a temperature in the range from 450 to 650.degree. C. for
within 5 hours during the step for reducing the thickness of the
alloy by cold rolling.
[0099] The strength and electric conductivity become insufficient
due to too low heat treatment temperature for precipitation by
aging, while the precipitates do not contribute to the strength
when the temperature is too high since the precipitates get coarse.
The temperature is preferably in the range from 480 to 620.degree.
C.
[0100] The heat treatment time for precipitation by aging is
preferably within 4 hours, and the lower limit thereof is 0.1
hour.
[0101] The strength and electric conductivity are further improved
by conducting the heat treatment steps for precipitation by aging
two or more times with a cold rolling step between the heat
treatment steps. The density of dislocations to be introduced in
the next cold rolling step may be increased by the fine compounds
precipitated in the first aging step, and the dislocations serve as
sites for forming a nucleus for precipitation in the second heat
treatment step and thereafter for precipitation by aging.
Consequently, the strength is further enhanced by increasing the
density of the precipitates. Accordingly, the condition for the
first aging step is preferably employed so that the highest density
of the precipitates is obtained.
[0102] The effect of the heat treatment for precipitation by aging
is remarkably emphasized by increasing the amount of the solute
atoms in the solid solution as large as possible before
precipitation of the atoms. In other words, properties such as high
strength, high electric conductivity and high stress relaxation
resistance may be manifested by forming a good solid solution state
before the heat treatment for precipitation by aging in order to
permit highly dense and fine precipitation state to be realized by
the heat treatment for precipitation by aging. The electric
conductivity is usually used as an index of the degree of the solid
solution, and the strength and stress relaxation resistance
property are improved when the electric conductivity before the
heat treatment for precipitation by aging is 35% IACS or less. The
strength and stress relaxation resistance become poor when the
electric conductivity is more than 35% IACS, since the amount of
the solute atoms that are finely precipitated in a high density is
small after the heat treatment for precipitation by aging. It is
more preferably 30% IACS or less.
[0103] The direction of final plastic working as used in the
present invention, in particular in the second embodiment of the
present invention, refers to the direction of rolling when the
rolling is the finally carried out plastic working, or to the
direction of drawing when the drawing (linear drawing) is the
plastic working finally carried out. The plastic working refers to
workings such as rolling and drawing, but working for the purpose
of leveling (vertical leveling) using, for example, a tension
leveler, is not included in this plastic working.
[0104] The copper alloy for the electric and electronic instruments
of the present invention may be favorably used, for example, for
connectors, terminals, relays and switches, and lead frames,
although its application is not restricted thereto.
[0105] According to the present invention, it is possible to
provide a novel copper alloy for the electric and electronic
instruments excellent in the strength, electric conductivity,
bending property and stress relaxation resistance property as well
as adhesiveness of solder.
[0106] The copper alloy of the present invention, in particular of
the first embodiment of the present invention, has performance of
600 MPa or more in the strength, 20% or less in the stress
relaxation rate after holding at 150.degree. C. for 1,000 hours,
50% IACS or more of the electric conductivity, and 1 or less of the
(R/t) ratio, which is an index of the bending property. The
metallic material is suitable for terminals, connectors, and relays
and switches for the electric and electronic instruments and
car-mounting parts.
[0107] The copper alloy of the present invention, in particular of
the second embodiment of the present invention, has performance of
650 MPa or more in the strength, 20% or less in the stress
relaxation rate after holding at 150.degree. C. for 1,000 hours and
55% IACS or more of the electric conductivity. The metallic
material is suitable for the terminals, connectors, and relays and
switches for the electric and electronic instruments.
[0108] The present invention will be described in more detail based
on examples given below, but the invention is not meant to be
limited by these.
EXAMPLES
Example 1
[0109] Alloys comprising Ni, Ti, Mg, Zr, Zn, Sn and Si in the
amounts as shown in Tables 1 to 4 with the balance of Cu were
melted in a high frequency melting furnace, and each molten alloy
was cast with a cooling rate in the range from 10 to 30.degree.
C./sec to give an ingot with a thickness of 30 mm, a width of 100
mm and a length of 150 mm. After holding the ingot at 1,000.degree.
C. for 1 hour, it was finished to a hot roll plate with a thickness
of about 10 mm using a hot rolling machine. Oxide films were
removed by shaving both surfaces of the hot roll plate to a depth
of about 1.0 mm. The plate was then cold-rolled to a thickness of
0.29 mm followed by subjecting to a solution heat treatment at
950.degree. C. for 15 second in an inert gas, and was cooled to
300.degree. C. over about 3 seconds (a cooling rate of about
300.degree. C./sec) after the solution heat treatment. The plate
was further cold-rolled to a thickness of 0.23 mm followed by an
aging treatment at 550.degree. C. for 2 hours. The plate was rolled
to a thickness of 0.2 mm followed by low temperature annealing at
350.degree. C. for 2 hours to provide plate materials of Examples 1
to 18 and 40 to 57 of the present invention, and Comparative
Examples 21 to 34, 60 to 67 and 70 to 73, as test pieces.
[0110] Each plate material thus obtained was investigated with
respect to [1] tensile strength, [2] electric conductivity, [3]
stress relaxation property (SR), [4] bending property (R/t), [5]
crystal grain size (GS), [6] size and density of precipitates (PPT)
and [7] adhesiveness of solder, by the methods described below. The
measuring methods for respective evaluation items are as
follows.
[1] Tensile Strength (TS)
[0111] Three JIS-13B test pieces cut in the direction parallel to
the roll direction were measured according to JIS-Z2241, and an
average value (MPa) was obtained.
[2] Electric Conductivity (EC)
[0112] Test pieces with a dimension of 10.times.150 mm was prepared
by cutting the plate in the direction parallel to the roll
direction, and the electric conductivity of two of the test pieces
was measured by the four-probe method in a constant-temperature
chamber controlled at 20.degree. C. (.+-.1.degree. C.) to obtain an
average value (% IACS). The distance between the probes was 100
mm.
[3] Stress Relaxation Property (SR)
[0113] According to the Electronic Materials Manufacturers
Association of Japan Standard EMAS-3003, the stress relaxation
property was measured at 150.degree. C. for 1,000 hours. FIG. 1 is
an explanatory view for illustrating the test method of stress
relaxation property. FIG. 1(a) is an explanatory view for
illustrating the measuring method of the initial deflection amount
.delta..sub.0. In FIG. 1(a), the reference numeral 1 denotes a test
piece, and the reference numeral 4 denotes a sample table. A load
of 80% of 0.2% yield strength (proof stress) was applied as an
initial stress using a cantilever method. And then, after the test
piece was kept at 150.degree. C. for 1,000 hours, it changed its
shape so as to return to the position represented by reference
numeral 2 in FIG. 1(b). The reference numeral 3 in FIG. 1(b)
denotes the position of the test piece without deflection. The
permanent deflection .delta..sub.t is represented by
H.sub.t-H.sub.1.
[0114] The stress relaxation rate (%) is represented by
.delta..sub.t/.delta..sub.0.times.100. This test is used for
assessing the stress change under a constant strain for a long time
when it is used for a terminal material or the like, and the alloy
is considered to be excellent as the stress relaxation rate is
smaller.
[4] Bending Property (R/t)
[0115] The plate material was cut in a dimension of 10 mm in the
width and 25 mm in the length (the direction of the length parallel
to the roll direction is defined as GW and the direction of the
length perpendicular to the roll direction is defined as BW), the
plate was bent with a bending radius R=0 at an angle of W
(90.degree.), and the presence of cracks at the bent portion was
observed using an optical microscope with 50 times magnification.
As an evaluation criterion, a critical bending radius giving no
cracks was measured and was expressed by R/t (R: bending radius, t:
thickness of the plate).
[5] Crystal Grain Size (GS)
[0116] The crystal texture before the final processing step was
observed using a scanning electron microscope (magnification of 200
to 1,000 times), and the crystal grain size was measured by the cut
method according to JIS-H0501.
[6] Precipitate (PPT)
[0117] The test material was punched to give a material with a
diameter of 3 mm, and the punched material was polished by a
twin-jet polishing method. A photograph of the polished sample was
taken using a transmission electron microscope with an acceleration
voltage of 300 kV and a magnification of 5,000 to 500,000 times,
and the grain size and density of the precipitates were measured
based on the photograph. Local deviation of the number of the
grains was eliminated by counting the number with n=10 (n denotes
the number of observation spots), when the grain size and density
were measured. The number obtained was converted into the number
per unit area (number/mm.sup.2).
[7] Adhesiveness of Solder
[0118] Adhesiveness of solder was tested according to the
explanatory view as schematically illustrated in FIG. 2. The test
piece was cut into a size of 20 mm.times.20 mm, and the surface of
the material was subjected to an electrolytic degreasing, as a
pre-treatment, to obtain a material 13 with a thickness of 6 mm. A
eutectic solder of Sn--Pb was piled on the surface of the material
13 to provide a solder portion 12. An iron wire 11 with a diameter
.phi. of 2 mm (a length of about 100 mm) prepared by coating a Fe
wire with Cu was fixed to the solder portion so that the material
13 was perpendicular to the wire 11 (FIG. 2(a)).
[0119] The test piece to which the wire 11 was joined was heated in
air, and solder joining strength between the iron wire 11 and the
material 13 was measured before and after the heating. The heating
condition was at 150.degree. C. for 500 hours in the constant
temperature chamber. After taking out of the chamber, the test
piece was sufficiently and gradually cooled (annealed) with air,
and the tensile strength was tested in the directions of the arrow
as shown in FIG. 2(b) to measure the load. The tensile strength was
measured at room temperature with a load cell speed of 10 mm/min.
The tensile strength was determined when the test material 13 was
peeled from the interface of the solder portion 12 and the test
material wire 11. The sample in which the test material was not
peeled from the interface but the iron wire 11 was pulled from the
solder portion 12 was not considered to be the object of
evaluation, since adhesiveness between the iron wire 11 and the
solder was judged to be poor.
[0120] The tensile strength before the heat treatment was also
measured as described above, to determine each strength of the test
material 13 before and after the heat treatment. The strength was
evaluated as ".largecircle." when the proportion of decrease of the
strength was 50% or less, and the strength was evaluated as "x"
when the proportion of decrease of the strength was 50% or more.
Solderability was considered to be excellent with high reliability
when the joining strength did not decrease with time (or the
material had a high residual strength).
[0121] The precipitate was identified by an observation using a
transmission electron microscope. Five to ten precipitates were
analyzed with an EDX analyzer (energy dispersive apparatus)
attached to the transmission electron microscope to confirm the
analysis peaks of Ni, Ti, Mg, Zr, Sn and Si. Diffraction patterns
were photographed with the transmission electron microscope, and it
was confirmed that the precipitates gave a different diffraction
pattern from that in which the Ni--Ti precipitate was formed. That
is, the different diffraction pattern shows that a precipitate
other than Ni--Ti was formed. The diffraction pattern was
identified and evaluated by selecting crystal grains containing 10
to 100 precipitates.
[0122] The results of evaluations [1] to [7] are also summarized in
Tables 1 to 4. TABLE-US-00001 TABLE 1 Ti PPT Adhesiveness This Ni
(mass Mg Zr Zn TS EC SR R/t R/t GS PPT (.times.10.sup.10/ of
invention (mass %) %) (mass %) (mass %) (mass %) (MPa) (% IACS) (%)
(GW) (BW) (.mu.m) (nm) mm.sup.2) solder 1 1.55 0.57 0.08 -- 0.51
601 55.3 19 0.5 0.5 4.4 20 21 .largecircle. 2 2.11 0.78 0.12 --
0.55 685 52.7 18 0.5 0.5 4.8 22 15 .largecircle. 3 2.54 0.94 0.14
-- 0.42 702 50.8 16 0.5 0.5 4.7 20 6 .largecircle. 4 2.90 1.07 0.18
-- 0.44 732 48.2 14 1.0 1.0 4.9 21 16 .largecircle. 5 1.56 0.58 --
0.07 0.51 605 55.7 17 0.5 0.5 4.8 20 163 .largecircle. 6 2.08 0.77
-- 0.11 0.25 675 52.0 15 0.5 0.5 4.8 23 65 .largecircle. 7 2.51
0.93 -- 0.13 0.55 694 50.2 14 0.5 0.5 4.9 41 156 .largecircle. 8
2.95 1.09 -- 0.19 0.60 745 49.0 12 1.0 1.0 4.1 20 5 .largecircle. 9
2.01 0.74 0.05 -- 0.44 681 53.8 19 0.5 0.5 4.2 23 5 .largecircle.
10 2.10 0.78 0.11 -- 0.50 710 51.7 16 0.5 0.5 4.3 33 15
.largecircle. 11 2.14 0.79 -- 0.05 0.52 723 50.8 18 0.5 0.5 4.3 22
54 .largecircle. 12 2.15 0.80 -- 0.05 0.46 727 50.6 15 0.5 0.5 4.4
21 62 .largecircle. 13 2.02 0.75 0.07 0.08 0.52 684 53.5 18 0.5 0.5
4.4 23 46 .largecircle. 14 2.05 0.76 0.10 0.10 0.51 694 52.9 14 0.5
0.5 4.8 12 5 .largecircle. 15 2.01 0.74 0.06 0.08 0.50 681 53.8 19
0.5 0.5 4 13 165 .largecircle. 16 2.17 0.80 0.09 0.06 0.70 733 50.1
15 0.5 0.5 4.2 33 6 .largecircle. 17 2.10 0.58 0.10 -- 0.23 710
51.7 17 0.5 0.5 4.9 8 12 .largecircle. 18 2.11 0.55 -- 0.11 0.66
714 51.5 16 0.5 0.5 4.3 32 165 .largecircle.
[0123] TABLE-US-00002 TABLE 2 Ni Ti Mg Adhesiveness Comparative
(mass (mass (mass Zr Zn TS EC SR R/t R/t GS PPT PPT of example %)
%) %) (mass %) (mass %) (MPa) (% IACS) (%) (GW) (BW) (.mu.m) (nm)
(.times.10.sup.10/mm.sup.2) solder 21 0.88 0.33 -- -- 0.45 506 59.3
41 0.5 0.5 4.2 23 123 .largecircle. 22 3.30 1.22 -- -- 0.34 701
38.2 33 2.0 2.0 12.4 24 15 .largecircle. 23 3.51 0.38 -- -- 0.44
488 32 48 1.5 1.5 13.3 22 53 .largecircle. 24 2.91 2.50 -- -- 0.54
685 32.7 33 2.0 2.0 13.2 12 6 .largecircle. 25 2.20 0.81 0.01 --
0.55 702 50.8 35 0.5 0.5 4.8 43 53 .largecircle. 26 2.10 0.78 0.55
-- 0.55 732 42.3 25 2.0 2.0 4.5 34 125 .largecircle. 27 2.08 0.77
-- 0.01 0.34 622 56.0 40 1.0 1.0 12.5 23 265 .largecircle. 28 2.12
0.79 -- 0.60 0.55 633 43.6 22 2.0 2.0 10.9 44 46 .largecircle. 29
2.11 0.78 0.005 0.007 0.23 612 55.4 44 1.0 1.0 11.5 45 15
.largecircle. 30 2.08 0.77 0.56 0.66 0.30 622 41.6 28 2.0 2.0 12.2
23 156 .largecircle. 31 2.53 0.94 0.20 -- -- 721 38.1 18 1.0 1.0
4.4 32 22 X 32 2.10 0.78 -- 0.13 -- 723 37.3 19 1.0 1.0 4.9 44 34 X
33 2.20 0.81 0.23 -- 1.50 712 39.3 19 0.5 0.5 5.5 34 54
.largecircle. 34 2.90 1.07 -- 0.30 2.02 733 38.3 19 0.5 0.5 3.9 54
43 .largecircle.
[0124] TABLE-US-00003 TABLE 3 Ni Ti Adhesiveness This (mass (mass
Sn Si Zn TS EC SR R/t R/t GS PPT PPT of invention %) %) (mass %)
(mass %) (mass %) (MPa) (% IACS) (%) (GW) (BW) (.mu.m) (nm)
(.times.10.sup.10/mm.sup.2) solder 40 1.64 0.65 0.08 -- 0.43 604
54.7 20 0.5 0.5 4.4 21 12 .largecircle. 41 2.16 0.79 0.13 -- 0.52
688 51.8 17 0.5 0.5 4.5 23 105 .largecircle. 42 2.63 1.03 0.15 --
0.36 705 50.8 14 0.5 0.5 4.5 27 98 .largecircle. 43 2.90 1.15 0.19
-- 0.42 735 47.6 12 1.0 1.0 4.6 22 15 .largecircle. 44 1.60 0.67 --
0.08 0.47 608 54.9 17 0.5 0.5 4.6 27 66 .largecircle. 45 2.08 0.86
-- 0.12 0.19 679 51.7 15 0.5 0.5 4.2 31 24 .largecircle. 46 2.57
0.96 -- 0.14 0.50 697 49.5 11 0.5 0.5 4.3 43 15 .largecircle. 47
2.97 1.13 -- 0.19 0.58 748 48.7 11 1.0 1.0 4.7 22 15 .largecircle.
48 2.08 0.75 0.06 -- 0.43 684 53.4 17 0.5 0.5 4.8 45 23
.largecircle. 49 2.14 0.82 0.15 -- 0.47 714 50.9 15 0.5 0.5 4.2 33
24 .largecircle. 50 2.22 0.82 -- 0.06 0.43 727 50.4 17 0.5 0.5 4.5
23 42 .largecircle. 51 2.25 0.84 -- 0.11 0.43 730 49.7 13 0.5 0.5
4.0 21 45 .largecircle. 52 2.03 0.76 0.08 0.09 0.52 688 53.0 16 0.5
0.5 4.2 25 16 .largecircle. 53 2.13 0.81 0.12 0.11 0.44 698 52.7 12
0.5 0.5 4.6 13 31 .largecircle. 54 2.02 0.78 0.07 0.08 0.42 684
53.2 20 0.5 0.5 4.4 15 156 .largecircle. 55 2.26 0.89 0.09 0.15
0.63 736 49.4 14 0.5 0.5 4.3 35 264 .largecircle. 56 2.16 0.65 0.10
-- 0.18 714 51.0 15 0.5 0.5 4.7 9 51 .largecircle. 57 2.17 0.58 --
0.12 0.63 717 51.0 14 0.5 0.5 4.7 36 55 .largecircle.
[0125] TABLE-US-00004 TABLE 4 Ni Ti Sn Adhesiveness Comparative
(mass (mass (mass Si Zn TS EC SR R/t R/t GS PPT PPT of example %)
%) %) (mass %) (mass %) (MPa) (% IACS) (%) (GW) (BW) (.mu.m) (nm)
(.times.10.sup.10/mm.sup.2) solder 60 0.95 0.42 -- -- 0.37 509 58.4
39 0.5 0.5 4.9 27 135 .largecircle. 61 3.33 1.25 -- -- 0.25 704
44.3 31 2.0 2.0 11.5 25 15 .largecircle. 62 3.59 0.44 -- -- 0.39
492 41.0 47 1.5 1.5 12.5 23 56 .largecircle. 63 2.91 2.50 -- --
0.47 688 38.3 32 2.0 2.0 12.2 13 5 .largecircle. 64 2.27 0.84 0.01
-- 0.50 705 50.2 33 0.5 0.5 4.4 45 42 .largecircle. 65 2.18 0.83
0.56 -- 0.53 735 41.4 24 2.0 2.0 4.2 34 12 .largecircle. 66 2.15
0.82 -- 0.01 0.26 626 55.0 39 1.0 1.5 10.5 27 26 .largecircle. 67
2.15 0.80 -- 0.62 0.47 636 43.2 22 2.0 2.0 10.2 44 66 .largecircle.
70 2.31 0.89 0.03 -- -- 711 50.7 33 0.5 0.5 4.1 34 33 X 71 2.22
0.85 0.26 -- -- 733 42.3 34 0.5 0.5 4.2 45 55 X 72 2.32 0.76 0.38
-- 1.47 699 39.0 24 1.0 1.0 4.9 37 34 .largecircle. 73 2.33 0.56 --
0.16 1.95 683 36.2 30 2.0 2.0 10.8 55 33 .largecircle.
[0126] As is clear from the Tables 1 and 3, the Examples 1 to 18
and 40 to 57 according to the present invention had good properties
with a stress relaxation resistance of 20% or less.
[0127] On the contrary, the Comparative Example 21 was poor in the
tensile strength, since a sufficient magnitude of precipitation
reinforcement could not be obtained due to a small amount Ni. In
addition, the stress relaxation rate was poor, since neither Mg nor
Zr was added.
[0128] Since the Comparative Example 22 required a high temperature
and a long time for the solution heat treatment due to large
contents of Ni and Ti, the crystal grains got coarse to make the
bending property poor. Further, the electric conductivity was also
poor, since excess Ni and Ti were solute in the host matrix even
after the aging treatment. In addition, the stress relaxation rate
was poor since neither Mg nor Zr was added.
[0129] The Comparative Example 23 was poor in the bending property
due to coarsened crystal grains since a large content of Ni
required a solution heat treatment at a high temperature for a long
time. In addition, the tensile strength was poor due to a poor
density of the Ni--Ti precipitates contributing to the strength
since the alloy contained an excess amount of Ni. Further, the
electric conductivity was poor due to an excess amount of Ni that
was solute in the host matrix even after the aging treatment.
Furthermore, the stress relaxation rate was poor since neither Mg
nor Zr was added.
[0130] Since the Comparative Example 24 required a high temperature
and long time of the solution heat treatment due to a large content
of Ti, the crystal grains got coarse to make the bending property
poor. In addition, the electric conductivity was poor due to an
excess amount of Ti that was solute in the host matrix even after
the aging treatment. Further, the stress relaxation rate was poor
since neither Mg nor Zr was added.
[0131] The Comparative Example 25 was poor in the stress relaxation
rate due to a small amount of precipitates comprising Ni, Ti and Mg
since the content of Mg was low.
[0132] Both the electric conductivity and the bending property were
poor in the Comparative Example 26 since excess Mg remained in the
solid solution, even after the aging treatment, due to a large
content of Mg. In addition, the stress relaxation rate was also
poor.
[0133] Since the Comparative Example 27 contained a small content
of Zr, the stress relaxation rate was poor due to a small content
of precipitates comprising Ni, Ti and Zr.
[0134] A large content of Zr in the Comparative Example 28 required
a high temperature and long time of the solution heat treatment, so
that the bending property was poor due to coarsening of crystal
grains. In addition, the electric conductivity was poor since
excess Zr was solute in the host matrix even after the aging
treatment. Further, the stress relaxation rate was also poor.
[0135] A small content of precipitates comprising Ni, Ti, Mg and Zr
resulted in a poor stress relaxation rate in the Comparative
Example 29, since it contained a small amount of each of Mg and
Zr.
[0136] The Comparative Example 30 required a high temperature and
long time of the solution heat treatment due to a large content of
each of Mg and Zr, and the bending property was poor due to
coarsening of crystal grains. In addition, the electric
conductivity was poor since excess Mg and Zr were solute in the
host matrix even after the aging treatment. Further, the stress
relaxation rate was also poor.
[0137] The adhesiveness of the solder was deteriorated since no Zn
was added in the Comparative Examples 31 and 32.
[0138] The electric conductivity was low in the Comparative
Examples 33 and 34 since a content of Zn was large.
[0139] The above-described Comparative Examples 21 to 34 correspond
to comparative examples that are comparable to the present
inventions described in the above items (1) and (2).
[0140] The tensile strength of the Comparative Example 60 was poor
since a sufficient magnitude of precipitation reinforcement could
not be attained due to a small content of Ni. In addition, the
stress relaxation ratio was poor since the density of the Ni--Ti
precipitates was insufficient, and neither Sn nor Si was added.
[0141] Since the Comparative Example 61 required a high temperature
and a long time for the solution heat treatment due to large
contents of Ni and Ti, the crystal grains got coarse to make the
bending property poor. Further, the electric conductivity was also
poor, since excess Ni and Ti were solute in the host matrix even
after the aging treatment. In addition, the stress relaxation rate
was poor since neither Sn nor Si was added.
[0142] The Comparative Example 62 was poor in the bending property
due to coarsened crystal grains since a large content of Ni
required a solution heat treatment at a high temperature for a long
time. In addition, the tensile strength was poor due to a low
density of the Ni--Ti precipitates contributing to the strength
since the alloy contained an excess amount of Ni. Further, the
electric conductivity was poor due to an excess amount of Ni that
was solute in the host matrix even after the aging treatment.
Furthermore, the stress relaxation rate was poor since neither Sn
nor Si was added.
[0143] A large content of Ti in the Comparative Example 63 required
a high temperature and long time of the solution heat treatment, so
that the bending property was poor due to coarsening of crystal
grains. In addition, the electric conductivity was poor since
excess Ti was solute in the host matrix even after the aging
treatment. Further, the stress relaxation rate was poor since
neither Sn nor Si was added.
[0144] Since the Comparative Example 64 contained a small content
of Sn, the stress relaxation rate was poor due to a small content
of precipitates comprising Ni, Ti and Sn.
[0145] Both the electric conductivity and the bending property were
poor in the Comparative Example 65 since excess Sn remained in the
solid solution due to a large content of Sn. In addition, the
stress relaxation rate was also poor.
[0146] Since the Comparative Example 66 contained a small content
of Si, the stress relaxation rate was poor due to a small content
of precipitates comprising Ni, Ti and Si.
[0147] A large content of Si in the Comparative Example 67 required
a high temperature and long time of the solution heat treatment, so
that the bending property was poor due to coarsening of crystal
grains. In addition, the electric conductivity was poor since
excess Si was solute in the host matrix. Further, the stress
relaxation rate was also poor.
[0148] The adhesiveness of the solder was deteriorated since no Zn
was added in the Comparative Examples 70 and 71.
[0149] The electric conductivity was low in the Comparative
Examples 72 and 73 since a content of Zn was large.
[0150] The above-described Comparative Examples 60 to 67 and 70 to
73 correspond to comparative examples that are comparable to the
present inventions described in the above items (3) and (4).
Example 2
[0151] The condition for the solution heat treatment and the
conditions for the subsequent cold rolling and aging were variously
changed using the alloy having the same composition as that of the
Sample No. 15 in the Example 1 above. Other production conditions
were the same as in Example 1. The evaluation items [1] to [7] were
conducted in the same manner as in Example 1. The solution heat
conditions and results of the evaluations are shown in Table 5.
TABLE-US-00005 TABLE 5 Solution heat treatment Aging Tempe- Cold
Tempe- EC PPT Adhesive- rature Time Cooling rolling rature Time TS
(% SR R/t R/t GS PPT (.times.10.sup.10/ ness (.degree. C.) (sec)
ratio (.degree. C./s) ratio (%) (.degree. C.) (hr) (MPa) IACS) (%)
(GW) (BW) (.mu.m) (nm) (mm.sup.2) of solder This invention 81 1000
15 330 20 550 2 690 52.9 18 0.75 0.75 6 17 187 .largecircle. 82 950
30 110 30 475 1 688 52.0 19 0.5 0.75 5 18 118 .largecircle. 83 950
15 70 10 550 2 677 54.1 18 0.5 0.5 5 13 231 .largecircle. 84 900 15
100 35 500 3 654 56.3 20 0.5 0.5 3 12 210 .largecircle. 85 950 5
200 25 525 1.5 690 52.9 19 0.5 0.5 4 11 103 .largecircle. 86 850 15
150 10 550 3 689 53.0 18 0.5 0.5 5 12 129 .largecircle. 87 950 15
300 20 525 3.5 681 53.8 19 0.5 0.5 4 13 165 .largecircle. 88 950 15
200 0 475 4 602 50.3 17 0 0 6 12 229 .largecircle. Compar- ative
example 91 950 15 35 20 525 3 622 57.2 24 0.5 0.5 5 13 65
.largecircle. 92 900 15 25 20 525 3 612 58.0 27 0.5 0.75 5 12 77
.largecircle. 93 800 15 110 20 525 3 639 56.9 26 0.75 0.75 3 10 52
.largecircle. 94 800 30 105 20 525 3 629 56.0 28 0.75 0.75 5 11 49
.largecircle. 95 950 60 130 20 525 3 690 52.9 18 1.5 1.5 11 12 223
.largecircle. 96 -None- -None- -None- >90 525 3 634 58.3 33
>2 >2 -- 8 169 .largecircle. 97 950 15 200 60 525 3 612 59.0
33 >2 >2 4 12 128 .largecircle. 98 950 15 200 20 625 3 561
59.4 34 0.75 0.75 6 667 4 .largecircle. 99 950 15 200 20 400 3 533
47.0 42 0.75 0.75 8 2 321 .largecircle. 100 950 15 200 20 525 7 553
59.7 32 0.75 0.75 3 333 3 .largecircle.
[0152] Table 5 shows that the Examples 81 to 88 had excellent
properties.
[0153] On the contrary, the stress relaxation rate was poor in the
Comparative Examples 91 and 92 since the precipitates got coarse
due to the slow cooling rate.
[0154] The smaller amount of elements contributing to the
precipitation was in the solid solution due to the low solution
heat temperature in the Comparative Example 93, and, therefore, the
stress relaxation rate was poor since the precipitation density was
decreased at the time of aging treatment.
[0155] The smaller amount of elements contributing to the
precipitation was in the solid solution due to the low solution
heat temperature in the Comparative Example 94, and, therefore, the
stress relaxation rate was poor since the precipitation density was
decreased at the time of solution heat treatment.
[0156] The bending property was poor in the Comparative Example 95
due to coarsening of crystal grains since the solution heat time
was long.
[0157] There caused no recrystallization in the Comparative Example
96 since no solution heat treatment was conducted. Therefore, the
measurement of the crystal grain size was impossible since the
crystalline texture was fibrous as a result of 90% or more of the
cold rolling ratio after the hot rolling. In addition, the bending
property and the stress relaxation rate were also poor since the
number of precipitations contributing to precipitation was
small.
[0158] The bending property was poor in the Comparative Example 97
due to high cold rolling ratio after the solution heat
treatment.
[0159] The strength was poor in the Comparative Example 98 due to
coarsening of precipitates since the aging temperature was
high.
[0160] The strength was poor in the Comparative Example 99 due to
fine size of precipitates since the aging temperature was low.
[0161] The strength was poor in the Comparative Example 100 due to
coarsening of precipitates since the aging time was long.
[0162] The above-described Comparative Examples 91 to 100
correspond to comparative examples that are comparable to the
present inventions described in the above items (5) and (6).
Example 3
[0163] The properties of the product of the present invention, such
as high electric conductivity, excellent strength, and excellent
stress relaxation resistance property, are exhibited by allowing a
Ni--Ti-series, Ni--Ti--Mg-series, Ni--Ti--Zr-series or other
multi-component intermetallic compounds based on Ni--Ti to finely
precipitate in high density in the Cu host matrix by a heat
treatment for annealing for precipitation by aging. For this
purpose, the amount in the solid solution of solute atoms should be
increased as much as possible in the state before precipitation by
aging, and the electric conductivity as an index of the degree of
the solid solution is preferably 35% IACS or less, more preferably
30% IACS or less. Therefore, conditions applied in the steps before
the heat treatment for precipitation by aging such as [1] casting
speed, [2] heating speed, holding temperature and holding time for
the subsequent homogenization heat treatment and [3] the subsequent
hot rolling, and cooling speed in the hot rolling, were adjusted as
follows.
[0164] Each alloy comprising Ni, Ti, Mg, Zn, Sn, Zr, Hf, In and Ag
in the amounts as shown in Tables 6 to 10 with the balance of Cu
was melted in a high frequency melting furnace, and cast to obtain
an ingot with a thickness of 30 mm, a width of 100 mm and a length
of 150 mm. The ingot was cooled at a cooling rate of 1 to
100.degree. C./sec.
[0165] After annealing the ingot at 800 to 1,050.degree. C. for 1
hour for homogenization, it was finished to a hot-rolled plate with
a thickness of about 10 mm by hot rolling. The temperature was
raised at a ratio of 3.degree. C./minute or more.
[0166] The hot rolling was conducted at a cooling rate of 10 to
300.degree. C./sec.
[0167] Oxide films were removed by shaving both surfaces of the
hot-rolled plate at a depth of about 1.0 mm, and a plate with a
thickness of 0.1 to 2 mm was obtained thereafter by cold rolling.
This plate was processed and heat-treated according to any one of
the steps 1 to 4, 5-1 to 5-4, 6-1 to 6-4 and 7-1 to 7-4 to obtain
each test material.
[Step 1]
[0168] The plate was subjected to solution heat treatment for 15 to
600 seconds at a temperature of 850 to 1,000.degree. C. in an inert
gas followed by cold rolling. Then, the plate was subjected to
annealing once for precipitation by aging at a temperature of 450
to 650.degree. C. within 5 hours, and the annealed plate was
subjected to final cold rolling at a rolling ratio of more than 0%
but 30% or less and stress-relief annealing at 150 to 500.degree.
C., to obtain a test material.
[Step 2]
[0169] The plate was subjected to solution heat treatment at a
temperature of 850 to 1,000.degree. C. for 15 to 600 seconds in an
inert gas after cold rolling. Then, the plate was alternately
subjected to once or more of cold rolling, and twice or more of
annealing for precipitation by aging at a temperature of 450 to
650.degree. C. for within 5 hours. The final aging annealed
material was finally cold-rolled at a rolling ratio in the range of
more than 0% but 30% or less and subjected to stress-relief
annealing at 150 to 500.degree. C., to obtain a test material.
[Step 3]
[0170] The plate after cold rolling was subjected to annealing for
precipitation by aging once at a temperature of 450 to 650.degree.
C. for within 5 hours. Then, the thus-obtained annealed material
was subjected to final cold rolling at a rolling ratio in the range
of 0% to 30% and stress-relief annealing at 150 to 500.degree. C.,
to obtain a test material.
[Step 4]
[0171] The plate was alternately subjected to twice or more of cold
rolling, and twice or more of annealing for precipitation by aging
at a temperature of 450 to 650.degree. C. for within 5 hours. Then,
the final aging annealed material was subjected to final cold
rolling at a rolling ratio in the range of more than 0% but 30% or
less and stress-relief annealing at 150 to 500.degree. C., to
obtain a test material.
[Steps 5-1 to 5-4]
[0172] One, or two or more times of the annealing for precipitation
by aging in Step 1, Step 2, Step 3 and Step 4 were performed at a
temperature exceeding 650.degree. C. These steps were referred to
as Steps 5-1 to 5-4, respectively.
[Steps 6-1 to 6-4]
[0173] One, or two or more times of the annealing for precipitation
by aging in Step 1, Step 2, Step 3 and Step 4 were performed at a
temperature lower than 450.degree. C. These steps were referred to
as Steps 6-1 to 6-4, respectively.
[Steps 7-1 to 7-4]
[0174] In Step 1, Step 2, Step 3 and Step 4, the plates were
annealed for precipitation by aging at a condition of the electric
conductivity before annealing for precipitation by aging exceeding
35% IACS. These steps were referred to as Steps 7-1 to 7-4,
respectively.
[0175] Each plate material thus obtained was investigated with
respect to [1] tensile strength (TS), [2] electric conductivity
(EC), [3] stress relaxation property (SR), [4] bending property,
[5] density of precipitates (PPT) and [6] adhesiveness of solder.
The evaluation methods of [1] tensile strength, [2] electric
conductivity, [3] stress relaxation property, [5] density of
precipitates and [6] adhesiveness of solder were the same as those
in Example 1. The evaluation method of the other evaluation item is
as follows.
[4] Bending Property (R/t)
[0176] The plate material was cut into a size of 0.5 mm in the
width and 25 mm in the length, and was bent at an angle W
(90.degree.) with the same bending radius (R) as the plate
thickness (t). The presence of cracks at the bent portion was
observed using an optical microscope with 50 times magnification.
With respect to evaluation criteria, samples with no cracks at the
surface of the bent portion were evaluated as ".largecircle.",
while samples with cracks at the surface of the bent portion were
evaluated as "x".
[0177] The precipitates were identified in the same manner as in
the Example 1.
[0178] The results of the evaluations [1] to [6] are listed
together in Tables 6 to 10. TABLE-US-00006 TABLE 6 Zn Mg Ni/Ti Step
TS EC Bending Adhesiveness No. Ni mass % Ti mass % mass % mass %
ratio No. MPa % IACS SR % property of solder PPT
.times.10.sup.12/mm.sup.2 This invention 201 2.01 0.63 0.51 0.11
3.19 1 655 55.8 16 .largecircle. .largecircle. 1 This invention 202
2.10 0.64 0.52 0.09 3.28 2 702 56.0 16 .largecircle. .largecircle.
1 This invention 203 1.81 0.56 0.49 0.11 3.23 3 670 61.2 19.5
.largecircle. .largecircle. 1 This invention 204 1.92 0.60 0.50
0.11 3.20 4 688 61.8 19 .largecircle. .largecircle. 1 This
invention 205 2.30 0.72 0.51 0.11 3.19 3 718 58.7 19 .largecircle.
.largecircle. 2 This invention 206 2.50 0.78 0.51 0.11 3.21 4 765
56.8 18 .largecircle. .largecircle. 3 This invention 207 1.50 0.47
0.52 0.09 3.19 2 668 57.2 16 .largecircle. .largecircle. 1 This
invention 208 1.30 0.40 0.52 0.09 3.25 2 659 58.1 16 .largecircle.
.largecircle. 1 This invention 209 1.80 0.50 0.50 0.06 3.60 2 675
57.0 17 .largecircle. .largecircle. 1 This invention 210 2.01 0.72
0.51 0.09 2.79 3 670 61.3 19 .largecircle. .largecircle. 1 This
invention 211 2.03 0.61 1.00 0.11 3.33 4 667 63.1 19.5
.largecircle. .largecircle. 1 This invention 212 1.81 0.56 3.00
0.12 3.23 2 685 55.8 17 .largecircle. .largecircle. 1 This
invention 213 2.03 0.60 0.49 0.15 3.38 4 685 61.5 19 .largecircle.
.largecircle. 1 This invention 214 1.81 0.60 0.50 0.20 3.02 3 670
61.2 18 .largecircle. .largecircle. 1 This invention 215 2.03 0.65
0.51 0.11 3.12 2 675 56.8 15 .largecircle. .largecircle. 3 This
invention 216 1.81 0.55 0.51 0.12 3.29 3 666 61.1 19.5
.largecircle. .largecircle. 0.3 Comparative 3.31 1.03 0.50 0.08
3.21 2 715 49.1 21 X .largecircle. 4 example 217 Comparative 0.71
0.22 0.51 0.09 3.23 2 620 58.1 24 .largecircle. .largecircle. 0.1
example 218 Comparative 2.01 0.37 0.48 0.09 5.43 3 655 51.3 27
.largecircle. .largecircle. 1 example 219 Comparative 2.03 1.35
0.50 0.12 1.50 3 660 48.2 22 .largecircle. .largecircle. 1 example
220 Comparative 1.81 0.52 0.00 0.12 3.48 2 665 58.6 20
.largecircle. X 1 example 221 Comparative 1.90 0.60 0.52 0.00 3.17
3 550 61.3 44 .largecircle. .largecircle. 1 example 222 Comparative
1.91 0.62 0.55 0.01 3.08 2 565 56.3 38 .largecircle. .largecircle.
1 example 223 Comparative 1.91 0.63 0.56 0.50 3.03 2 670 45.4 19 X
.largecircle. 1 example 224 Comparative 1.95 0.66 0.51 0.10 2.95 3
621 43.1 27 .largecircle. .largecircle. 0.0001 example 225
Comparative 2.01 0.60 0.52 0.13 3.35 4 670 56.8 22 X .largecircle.
100 example 226 Comparative 1.81 0.52 7.02 0.10 3.48 2 651 45.2 22
.largecircle. .largecircle. 1 example 226-1
[0179] TABLE-US-00007 TABLE 7 Ni mass Ti Zn Mg Sn Ni/Ti Step TS EC
Bending Adhesiveness No. % mass % mass % mass % mass % ratio No.
MPa % IACS SR % property of solder PPT .times.10.sup.12/mm.sup.2
This invention 227 2.01 0.63 0.51 0.11 0.15 3.19 1 685 55.6 16
.largecircle. .largecircle. 1 This invention 228 2.10 0.64 0.52
0.09 0.2 3.28 2 693 56.4 16 .largecircle. .largecircle. 1 This
invention 229 1.81 0.56 0.49 0.11 0.3 3.23 3 688 60.1 18
.largecircle. .largecircle. 1 This invention 230 1.92 0.60 0.50
0.11 0.12 3.20 4 690 59.6 19 .largecircle. .largecircle. 1 This
invention 231 2.01 0.63 0.51 0.11 0.08 3.19 2 666 55.7 16
.largecircle. .largecircle. 1 This invention 232 2.10 0.64 0.52
0.09 0.09 3.28 2 710 55.9 16 .largecircle. .largecircle. 1 This
invention 233 1.81 0.56 0.49 0.11 0.07 3.23 3 680 60.2 19
.largecircle. .largecircle. 1 This invention 234 1.92 0.60 0.50
0.11 0.08 3.20 4 695 61.1 19 .largecircle. .largecircle. 1 This
invention 235 2.30 0.72 0.51 0.11 0.08 3.19 3 725 58.0 19
.largecircle. .largecircle. 2 This invention 236 2.50 0.78 0.51
0.11 0.09 3.21 4 770 56.1 18 .largecircle. .largecircle. 3 This
invention 237 1.50 0.47 0.52 0.09 0.07 3.19 2 675 56.5 16
.largecircle. .largecircle. 1 This invention 238 1.30 0.40 0.52
0.09 0.08 3.25 2 670 58.0 16 .largecircle. .largecircle. 1 This
invention 239 1.80 0.50 0.50 0.06 0.08 3.60 2 686 56.3 17
.largecircle. .largecircle. 1 This invention 240 2.01 0.72 0.51
0.09 0.09 2.79 3 682 60.5 19 .largecircle. .largecircle. 1 This
invention 241 2.03 0.61 1.00 0.11 0.07 3.33 4 680 62.5 19.5
.largecircle. .largecircle. 1 This invention 242 1.81 0.56 3.00
0.12 0.08 3.23 2 693 55.6 17 .largecircle. .largecircle. 1 This
invention 243 2.03 0.60 0.49 0.15 0.08 3.38 4 695 60.7 19
.largecircle. .largecircle. 1 This invention 244 1.81 0.60 0.50
0.20 0.09 3.02 3 681 60.6 19 .largecircle. .largecircle. 1 This
invention 245 2.03 0.65 0.51 0.11 0.07 3.12 2 686 56.5 15
.largecircle. .largecircle. 3 This invention 246 1.81 0.55 0.51
0.12 0.08 3.29 3 678 60.3 19.5 .largecircle. .largecircle. 0.3
Comparative 3.31 1.03 0.50 0.08 0.09 3.21 2 715 49.1 22 X
.largecircle. 4 example 247 Comparative 0.71 0.22 0.51 0.09 0.07
3.23 2 620 58.9 25 .largecircle. .largecircle. 0.1 example 248
Comparative 2.01 0.37 0.48 0.09 0.08 5.43 3 655 50.5 28
.largecircle. .largecircle. 1 example 249 Comparative 2.03 1.35
0.50 0.12 0.08 1.50 3 660 48.1 22 .largecircle. .largecircle. 1
example 250 Comparative 1.81 0.52 0.00 0.12 0.09 3.48 2 665 59.1 20
.largecircle. X 1 example 251 Comparative 1.90 0.60 0.52 0.00 0.07
3.17 3 550 52.2 45 .largecircle. .largecircle. 1 example 252
Comparative 1.91 0.62 0.55 0.01 0.08 3.08 2 565 50.9 38
.largecircle. .largecircle. 1 example 253 Comparative 1.91 0.63
0.56 0.50 0.09 3.03 2 670 45.1 20 X .largecircle. 1 example 254
Comparative 1.95 0.66 0.51 0.10 0.07 2.95 3 621 47.8 27
.largecircle. .largecircle. 0.0001 example 255 Comparative 2.01
0.60 0.52 0.13 0.08 3.35 4 670 56.1 22 X .largecircle. 100 example
256 Comparative 1.81 0.52 0.52 0.12 2 3.48 2 680 48.1 20
.largecircle. .largecircle. 1 example 257 Comparative 1.90 0.60
0.52 0.12 1.51 3.17 3 675 40.2 20 .largecircle. .largecircle. 1
example 258 Comparative 1.81 0.52 7.02 0.10 0.09 3.48 2 651 43.2 22
.largecircle. .largecircle. 1 example 258-1
[0180] TABLE-US-00008 TABLE 8 Ni Ti Zn Mg Other Ni/Ti Step TS EC
Bending Adhesiveness PPT .times.10.sup.12/ No. mass % mass % mass %
mass % mass % ratio No. MPa % IACS SR % property of solder mm.sup.2
This invention 259 1.82 0.59 0.52 0.08 0.05 Zr 3.08 2 692 56.8 18
.largecircle. .largecircle. 1 This invention 260 1.85 0.51 0.55
0.09 0.04 Hf 3.63 3 685 60.5 19.5 .largecircle. .largecircle. 1
This invention 261 1.79 0.53 0.52 0.12 0.05 In 3.38 4 680 62.2 19
.largecircle. .largecircle. 1 This invention 262 1.79 0.53 0.52
0.12 0.1 Ag 3.38 4 702 60.2 19 .largecircle. .largecircle. 1
Comparative 1.82 0.59 0.52 0.08 1.02 Zr 3.08 2 675 46.2 20 X
.largecircle. 1 example 263 Comparative 1.85 0.51 0.55 0.09 1.10 Hf
3.63 3 670 44.3 22 X .largecircle. 1 example 264 Comparative 1.79
0.53 0.52 0.12 1.20 In 3.38 4 676 38.9 21 X .largecircle. 1 example
265 Comparative 1.79 0.53 0.52 0.12 1.3 Ag 3.38 4 685 48.0 20 X
.largecircle. 1 example 266
[0181] TABLE-US-00009 TABLE 9 Ni Ti Zn mass mass mass Mg Sn Other
Ni/Ti Step TS EC Bending Adhesiveness PPT .times.10.sup.12/ No. % %
% mass % mass % mass % ratio No. MPa % IACS SR % property of solder
mm.sup.2 This invention 267 1.82 0.59 0.52 0.08 0.09 0.05 Zr 3.08 2
702 56.1 18 .largecircle. .largecircle. 1 This invention 268 1.85
0.51 0.55 0.09 0.07 0.04 Hf 3.63 3 693 59.5 19.5 .largecircle.
.largecircle. 1 This invention 269 1.79 0.53 0.52 0.12 0.09 0.05 In
3.38 4 690 61.1 19 .largecircle. .largecircle. 1 This invention 270
1.79 0.53 0.52 0.12 0.09 0.1 Ag 3.38 4 705 59.5 19 .largecircle.
.largecircle. 1 Comparative 1.82 0.59 0.52 0.08 0.09 1.02 Zr 3.08 2
680 45.5 20 X .largecircle. 1 example 271 Comparative 1.85 0.51
0.55 0.09 0.07 1.10 Hf 3.63 3 675 42.5 22 X .largecircle. 1 example
272 Comparative 1.79 0.53 0.52 0.12 0.09 1.20 In 3.38 4 684 39.0 21
X .largecircle. 1 example 273 Comparative 1.79 0.53 0.52 0.12 0.09
1.3 Ag 3.38 4 692 45.3 20 X .largecircle. 1 example 274
[0182] TABLE-US-00010 TABLE 10 Ni Ti Zn Mg Sn Ni/Ti Step TS EC
Bending Adhesiveness No. mass % mass % mass % mass % mass % ratio
No. MPa % IACS SR % property of solder PPT
.times.10.sup.12/mm.sup.2 Comparative 2.01 0.63 0.51 0.11 -- 3.19
5-1 556 65.1 28 .largecircle. .largecircle. 0.0004 example 275
Comparative 1.81 0.56 0.49 0.11 -- 3.23 5-2 540 66.0 27
.largecircle. .largecircle. 0.0003 example 276 Comparative 1.81
0.56 0.49 0.11 0.08 3.23 5-3 570 65.1 29 .largecircle.
.largecircle. 0.0003 example 277 Comparative 2.01 0.63 0.51 0.11 --
3.19 6-1 535 44.2 30 .largecircle. .largecircle. 0.0002 example 278
Comparative 1.81 0.56 0.49 0.11 -- 3.23 6-3 542 42.5 32
.largecircle. .largecircle. 0.0001 example 279 Comparative 1.81
0.56 0.49 0.11 0.08 3.23 6-2 551 41.8 30 .largecircle.
.largecircle. 0.0001 example 280 Comparative 2.01 0.63 0.51 0.11 --
3.19 7-4 575 66.2 28 .largecircle. .largecircle. 0.0001 example 281
Comparative 1.81 0.56 0.49 0.11 -- 3.23 7-3 545 68.1 29
.largecircle. .largecircle. 0.0001 example 282 Comparative 1.81
0.56 0.49 0.11 0.08 3.23 7-2 560 65.1 28 .largecircle.
.largecircle. 0.0001 example 283 This 2.01 0.63 0.51 0.11 -- 3.19 1
655 55.8 16 .largecircle. .largecircle. 1 invention 201 This 2.10
0.64 0.52 0.09 0.2 3.28 2 693 56.4 16 .largecircle. .largecircle. 1
invention 228 This 1.81 0.56 0.49 0.11 0.3 3.23 3 688 60.1 18
.largecircle. .largecircle. 1 invention 229 This 1.92 0.60 0.50
0.11 -- 3.20 4 688 61.8 19 .largecircle. .largecircle. 1 invention
204
[0183] As is clear from Table 6, the Examples 201 to 216 according
to the present invention had excellent properties, such as tensile
strength of 650 MPa or more, electric conductivity of 55% IACS or
more and stress relaxation rate of 20% or less.
[0184] On the contrary, high temperature and long time of solution
heat treatment was necessary due to a large content of Ni in the
Comparative Example 217, and the bending property was poor as a
result of coarsening of crystal grains. Further, the electric
conductivity was also poor since an amount of Ni in the solid
solution was large.
[0185] The Comparative Example 218 was poor in the tensile
strength, since a sufficient magnitude of precipitation
reinforcement could not be obtained due to a small amount Ni.
[0186] The electric conductivity was poor in the Comparative
Examples 219 and 220 due to an increased amount of elements in the
solid solution since the Ni/Ti ratio was out of the range
prescribed in the present invention.
[0187] The adhesiveness of solder was deteriorated in the
Comparative Example 221 since no Zn was added.
[0188] The strength of the Comparative Examples 222 and 223 was
insufficient due to a small amount of precipitates comprising Ni,
Ti and Mg since no Mg or a too small amount of Mg was added. In
addition, the stress relaxation rate was also poor due to a small
amount of Mg in the solid solution.
[0189] Excess Mg remained in the solid solution even by aging
treatment in the Comparative Example 224 since the amount of Mg was
in excess, so that both the electric conductivity and the bending
property were poor.
[0190] The strength and the stress relaxation rate were poor in the
Comparative Example 225 since the density of precipitates was
low.
[0191] Coarse precipitates were readily formed at grain boundaries
in the Comparative Example 226 due to a high density of
precipitates, so that the bending property was poor.
[0192] The electric conductivity was decreased in the Comparative
Example 226-1 since a large amount of Zn added caused Zn to remain
in the solid solution.
[0193] The above-described Comparative Examples 217 to 226 and
226-1 correspond to comparative examples that are comparable to the
present inventions described in the above item (7).
[0194] As is clear from Table 7, the Examples 227 to 246 according
to the present invention had excellent properties, such as tensile
strength of 650 MPa or more, electric conductivity of 55% IACS or
more and stress relaxation rate of 20% or less.
[0195] On the contrary, high temperature and long time of solution
heat treatment was necessary due to a large content of Ni in the
Comparative Example 247, and the bending property was poor as a
result of coarsening of crystal grains. Further, the electric
conductivity was also poor since an amount of Ni in the solid
solution was large.
[0196] The Comparative Example 248 was poor in the tensile
strength, since a sufficient magnitude of precipitation
reinforcement could not be obtained due to a small amount Ni.
[0197] The electric conductivity was poor in the Comparative
Examples 249 and 250 due to an increased amount of elements in the
solid solution since the Ni/Ti ratio was out of the range
prescribed in the present invention.
[0198] The adhesiveness of solder was deteriorated in the
Comparative Example 251 since no Zn was added.
[0199] The strength of the Comparative Examples 252 and 253 was
insufficient due to a small amount of precipitates comprising Ni,
Ti and Mg since no Mg or a too small amount of Mg was added. In
addition, the stress relaxation rate was also poor due to a small
amount of Mg in the solid solution.
[0200] Excess Mg remained in the solid solution even by aging
treatment in the Comparative Example 254 since the amount of Mg was
in excess, so that both the electric conductivity and the bending
property were poor.
[0201] The strength and the stress relaxation rate were poor in the
Comparative Example 255 since the density of precipitates was
low.
[0202] Coarse precipitates were readily formed at grain boundaries
in the Comparative Example 256 due to a high density of
precipitates, so that the bending property was poor.
[0203] The electric conductivity was poor in the Comparative
Examples 257 and 258, since an amount of Sn was large.
[0204] The electric conductivity was decreased in the Comparative
Example 258-1 since a large amount of Zn added caused Zn to remain
in the solid solution.
[0205] The above-described Comparative Examples 247 to 258 and
258-1 correspond to comparative examples that are comparable to the
present invention described in the above item (8).
[0206] As is clear from Table 8, the Examples 259 to 262 according
to the present invention had excellent properties, such as tensile
strength of 650 MPa or more, electric conductivity of 55% IACS or
more and stress relaxation rate of 20% or less.
[0207] On the contrary, an excess amount of Zr in the Comparative
Example 263 caused excess Zr to remain in the solid solution to
deteriorate both the electric conductivity and the bending
property.
[0208] An excess amount of Hf in the Comparative Example 264 caused
excess Hf to remain in the solid solution to deteriorate both the
electric conductivity and the bending property.
[0209] An excess amount of In in the Comparative Example 265 caused
excess In to remain in the solid solution to deteriorate both the
electric conductivity and the bending property.
[0210] An excess amount of Ag in the Comparative Example 266 caused
excess Ag to remain in the solid solution to deteriorate both the
electric conductivity and the bending property.
[0211] The above-described Comparative Examples 263 to 266
correspond to comparative examples that are comparable to the
present invention described in the above item (9).
[0212] As is clear from Table 9, the Examples 267 to 270 according
to the present invention had excellent properties, such as tensile
strength of 650 MPa or more, electric conductivity of 55% IACS or
more and stress relaxation rate of 20% or less.
[0213] On the contrary, an excess amount of Zr in the Comparative
Example 271 caused excess Zr to remain in the solid solution to
deteriorate both the electric conductivity and the bending
property.
[0214] An excess amount of Hf in the Comparative Example 272 caused
excess Hf to remain in the solid solution to deteriorate both the
electric conductivity and the bending property.
[0215] An excess amount of In in the Comparative Example 273 caused
excess In to remain in the solid solution to deteriorate both the
electric conductivity and the bending property.
[0216] An excess amount of Ag in the Comparative Example 274 caused
excess Ag to remain in the solid solution to deteriorate both the
electric conductivity and the bending property.
[0217] The above-described Comparative Examples 271 to 274
correspond to comparative examples that are comparable to the
present invention described in the above item (10).
[0218] As is clear from Table 10, the Examples 201, 228, 229 and
204 according to the present invention had excellent properties,
such as tensile strength of 650 MPa or more, electric conductivity
of 55% IACS or more and stress relaxation rate of 20% or less.
[0219] On the contrary, the density of precipitates was low due to
a too high aging temperature in the Comparative Examples 275 to
277, and the strength and the stress relaxation rate were poor.
[0220] The amount of precipitates was insufficient due to a too low
aging temperature in the Comparative Example 278 to 280, so that
the density of the precipitates was low to result in poor strength,
electric conductivity and stress relaxation rate.
[0221] The density of the precipitate after the heat treatment for
precipitation by aging was low and the strength and stress
relaxation rate was poor in the Comparative Examples 281 to 283,
since the samples having an electric conductivity of 35% IACS or
more before the heat treatment for precipitation by aging were
subjected to the heat treatment for precipitation by aging.
[0222] The above-described Comparative Examples 275 to 283
correspond to comparative examples that are comparable to the
present invention described in the above item (11).
INDUSTRIAL APPLICABILITY
[0223] The copper alloy of the present invention can be favorably
applied for connectors of electric and electronic instruments,
connectors of terminals, materials of terminals, and the like.
[0224] Having described our invention as related to the present
embodiments, it is our intention that the invention not be limited
by any of the details of the description, unless otherwise
specified, but rather be construed broadly within its spirit and
scope as set out in the accompanying claims.
[0225] This non-provisional application claims priority under 35
U.S.C. .sctn. 119 (a) on Patent Application No. 2004-165068 filed
in Japan on Jun. 2, 2004, and Patent Application No. 2005-161475
filed in Japan on Jun. 1, 2005, each of which is entirely herein
incorporated by reference.
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