U.S. patent application number 12/226769 was filed with the patent office on 2009-12-24 for multicomponent copper alloy and its use.
Invention is credited to Maher Ababneh, Hans-Achim Kuhn, Volker Voggeser.
Application Number | 20090317290 12/226769 |
Document ID | / |
Family ID | 38294073 |
Filed Date | 2009-12-24 |
United States Patent
Application |
20090317290 |
Kind Code |
A1 |
Ababneh; Maher ; et
al. |
December 24, 2009 |
Multicomponent Copper Alloy and Its Use
Abstract
The invention relates to a multicomponent copper alloy
comprising [in % by weight]: Ni from 1.0 to 15.0%, Sn from 2.0 to
12.0%, Mn from 0.1 to 5.0%, Si from 0.1 to 3.0%, balance Cu and
unavoidable impurities, if desired up to 0.5% of P, if desired
individually or in combination up to 1.5% of Ti, Co, Cr, Al, Fe,
Zn, Sb, if desired individually or in combination up to 0.5% of B,
Zr, S, if desired up to 5% of Pb, and having Mn--Ni silicide phases
which have a mass ratio of the elements [w(Mn)+w(Ni)]/w(Si) in the
range from 1.8/1 to 7/1.
Inventors: |
Ababneh; Maher; (Ulm,
DE) ; Kuhn; Hans-Achim; (Illertissen, DE) ;
Voggeser; Volker; (Dietenheim, DE) |
Correspondence
Address: |
FLYNN THIEL BOUTELL & TANIS, P.C.
2026 RAMBLING ROAD
KALAMAZOO
MI
49008-1631
US
|
Family ID: |
38294073 |
Appl. No.: |
12/226769 |
Filed: |
April 26, 2007 |
PCT Filed: |
April 26, 2007 |
PCT NO: |
PCT/EP2007/003688 |
371 Date: |
January 26, 2009 |
Current U.S.
Class: |
420/473 ;
148/412; 148/433 |
Current CPC
Class: |
F16C 2204/10 20130101;
F16C 33/121 20130101; C22C 9/06 20130101; C22C 1/06 20130101; C22C
9/02 20130101 |
Class at
Publication: |
420/473 ;
148/433; 148/412 |
International
Class: |
C22C 9/02 20060101
C22C009/02 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 28, 2006 |
DE |
10 2006 019 827.1 |
Claims
1. Multicomponent copper alloy consisting of [in % by weight]: Ni
1.0 to 15.0%, Sn 2.0 to 12.0%, Mn 0.1 to 5.0%, Si 0.1 to 3.0%,
remainder Cu and unavoidable impurities, optionally up to 0.5% P,
optionally individually or in combination up to 1.5% Ti, Co, Cr,
Al, Fe, Zn, Sb, optionally individually or in combination up to
0.5% B, Zr, S, optionally up to 5% Pb, with Mn--Ni silicide phases,
which have a mass ratio of the elements [w(Mn)+w(Ni)]/w(Si) in the
range of from 1.8/1 to 7/1.
2. Multicomponent copper alloy according to claim 1, characterized
in that the mass fraction of the elements satisfies the following
relationship: [w(Ni)-w(Mn)-w(Sn)]>0.
3. Multicomponent copper alloy according to claim 1, characterized
in that the mass fraction of the elements satisfies the following
relationship: w(Mn)>w(Si).
4. Multicomponent copper alloy according to claim 1, characterized
in that the value of the elongation at break A.sub.5 at a
temperature of 400.degree. C. is more than 10%.
5. Multicomponent copper alloy according to claim 1, characterized
in that the crystallite size of the Mn--Ni silicide phases is from
0.1 to 100 .mu.m.
6. Multicomponent copper alloy according to claim 1, characterized
in that it contains from 0.01 to 0.06% P, finely distributed Ni
phosphide phases being formed in the matrix.
7. Multicomponent copper alloy according to claim 6, characterized
in that the average grain size of the finely distributed Ni
phosphide phases is less than 100 nm.
8. Multicomponent copper alloy according to claim 1, characterized
in that it contains from 0.1 to 2.5% Mn and from 0.1 to 1.5%
Si.
9. Multicomponent copper alloy according to claim 8, characterized
in that it contains from 0.1 to 1.6% Mn and from 0.1 to 0.7%
Si.
10. Multicomponent copper alloy according to claim 1, characterized
in that it has undergone at least one heat treatment at from 300 to
500.degree. C.
11. Multicomponent copper alloy according to claim 1, characterized
in that it has undergone at least one heat treatment at from 600 to
800.degree. C.
12. Multicomponent copper alloy according to claim 1, characterized
in that it has undergone a combination of at least one solution
anneal at from 600 to 800.degree. C. and at least one age hardening
at from 300 to 500.degree. C.
13. Use of the multicomponent copper alloy according to claim 1 for
friction-bearing elements or jack connectors.
Description
[0001] The invention relates to a multicomponent copper alloy and
to its use.
[0002] Wrought alloys based on copper-nickel-tin have been known
for a long time. For example, U.S. Pat. No. 1,535,542 describes
such an alloy in conjunction with the aim of improving the material
properties with respect to corrosion resistance, ductility and
formability.
[0003] U.S. Pat. No. 1,816,509 discloses a copper-nickel-tin alloy
and a method for the further treatment of such alloys. After
casting the alloy, the method involves a cold forming process and,
in order to adjust particular material properties, a heat treatment
for homogenizing and age hardening the alloy. The heat treatment
leads to continuous and discontinuous precipitates with the
formation of a further .gamma. phase.
[0004] Specification DE 41 21 994 C2 discloses a further method by
which a copper-nickel-tin alloy as a wrought alloy for
friction-bearing element applications undergoes conventional steps
of casting and forming, the .gamma. phase being formed as
continuous and discontinuous precipitates by a heat treatment after
the last cold forming. The volume fraction of the .gamma. phase
which is formed depends on the process management selected for the
heat treatment.
[0005] Further to this, numerous studies have been carried out in
the system of copper-nickel-tin alloys (U.S. Pat. No. 4,142,918,
U.S. Pat. No. 4,406,712 and WO 2005/108631 A1) in order constantly
to refine the material properties. In practice, it has however been
found that many property combinations, for example wear resistance
and thermal stability, cannot be optimized simultaneously by the
known process technology. The improvement in one material property
is then obtained at the cost of another property, which is likewise
important for certain application fields.
[0006] It is therefore an object of the invention to refine a
multicomponent copper alloy so that both a high, mechanical wear
resistance and a high thermal stability are achieved.
[0007] The invention is characterized with respect to a
multicomponent copper alloy by the features of claim 1 and with
respect to a use by the features of claim 13. The other dependent
claims relate to advantageous configurations and refinements of the
invention.
[0008] The invention provides a multicomponent copper alloy
consisting of [in % by weight]:
Ni 1.0 to 15.0%,
Sn 2.0 to 12.0%,
Mn 0.1 to 5.0%,
Si 0.1 to 3.0%,
[0009] remainder Cu and unavoidable impurities, optionally up to
0.5% P, optionally individually or in combination up to 1.5% Ti,
Co, Cr, Al, Fe, Zn, Sb, optionally individually or in combination
up to 0.5% B, Zr, S, optionally up to 5% Pb, with Mn--Ni silicide
phases, which have a mass ratio of the elements [w(Mn)+w(Ni)]/w(Si)
in the range of from 1.8/1 to 7/1.
[0010] The invention is based on the idea of providing a
multicomponent copper alloy which simultaneously offers very good
wear resistance and, particularly for use as a friction-bearing
element in a thermally stressed environment, excellent thermal
stability. With silicon or manganese contents exceeding the
specified maximum values of 3% by weight and 5% by weight,
respectively, the alloy is susceptible to embrittlement which
entails difficulties in the further treatment, in particular owing
to edge cracks in the strip material during rolling. Addition of
the elements Ti, Co, Cr and Fe leads to the formation of further
silicide phases. Sb and Al may be added owing to the improvement in
the low-friction properties or the corrosion resistance. The
further elements B, Zr and S serve to deoxidize the melt or make a
contribution to the grain refinement. The element phosphorus
likewise serves for deoxidation, although it can also form
phosphide phases which make an important contribution to increasing
the hardness of the matrix. The element lead is relevant to the
production of cast alloys, while in wrought alloys it is not
present or present in very small amounts.
[0011] The Mn--Ni silicide phases according to the invention, which
have a mass ratio of the elements [w(Mn)+w(Ni)]/w(Si) in the range
of from 1.8/1 to 7/1, serve in particular to increase the contact
area ratio in friction-bearing element applications. Particularly
with somewhat increased manganese proportions, the alloy according
to the invention having Mn--Ni silicide phases forms an
increasingly fine grain structure which in principle leads to an
advantageous increase in the elongation at break A5.
[0012] The wrought Cu--Ni--Sn alloys according to the invention are
spinoidally demixing systems, which are particularly suitable as
bearing materials in motor construction as a solid material and in
composite friction-bearing elements. These materials have good
friction and wear properties as well as good corrosion resistance.
The thermal stability is also excellent.
[0013] With Ni contents of from 1 to 15% by weight and Sn contents
of from 2 to 12% by weight, cold forming factors of up to 60% can
be achieved for these materials. In combination with soft
annealing, it is possible to produce thin strips suitable for
material composites. These alloys may also be age hardened in the
temperature range between 300 and 500.degree. C. The material is
thereby strengthened owing to the spinoidal demixing which takes
place. Furthermore, continuous or discontinuous precipitates may be
generated. This form of precipitation hardening is far superior to
binary copper-based alloys.
[0014] Compared with copper-based alloys and conventional
Cu--Ni--Sn alloys, the advantages achieved by the invention are in
particular that the material properties can be adapted optimally to
the respective task by means of rolling, homogenization annealing
and age hardening. For example, a softer or harder multicomponent
copper alloy may be combined by mechanical and thermal treatment in
composite friction-bearing elements with harder materials, for
example steel.
[0015] Advantageously, the mass fraction of the elements satisfies
the following relationship: [w(Ni)-w(Mn)-w(Sn)]>0. In other
words, the nickel content is greater than the tin and manganese
contents together, since nickel should be contained both for the
silicide formation and for the spinoidal demixing in the ideal case
in the same proportions as tin. Not only are intermetallic phases
thereby formed, which increase the contact area ratio in
friction-bearing applications and also reduce the wear in jack
connectors. In parallel with this, a hardness increase through
spinoidal demixing can be achieved with respect to the matrix by a
heat treatment.
[0016] In an advantageous configuration, the mass fraction of the
elements may satisfy the following relationship: w(Mn)>w(Si). If
the manganese content is more than the silicon content, sufficient
manganese will be available for the silicide formation.
Surprisingly, further grain refining is observed in the matrix when
the manganese content is increased beyond the silicon content.
[0017] Advantageously, the value of the elongation at break A.sub.5
at a temperature of 400.degree. C. is more than 10%. The alloy
according to the invention therefore exhibits ductile behavior.
This is primarily attributable to grain refining. In a temperature
range of from room temperature to about 400.degree. C., the
elongation at break lies at an almost constant level of 18-20%.
Comparable alloys without silicide components, conversely, exhibit
a pronouncedly brittle behavior. For these alloys, under the same
conditions, an elongation at break value of from 8 to 15% is
obtained, although this falls to a value of only 4% beyond about
300.degree. C. This effect is analogous to the so-called strain
ageing effect to be observed in long-term stored or heat treated
seals. A comparable embrittling effect is also known for
bronzes.
[0018] In a preferred configuration, the crystallite size of the
Mn--Ni silicide phases may be from 0.1 to 100 .mu.m. In this case
there are sometimes also elongated particles in the matrix. For
friction-bearing applications, such particle sizes are particularly
advantageous with respect to the friction-bearing pair in
question.
[0019] The alloy may advantageously contain from 0.01 to 0.06% P,
finely distributed Ni phosphide phases being formed in the matrix.
These phases have a hardness increasing effect for the matrix. Even
with a proportion of about 100 ppm, a significant increase in the
hardness can be achieved. Advantageously, the average grain size of
the finely distributed Ni phosphide phases may be less than 100
nm.
[0020] In a particular configuration of the invention, the
multicomponent copper alloy may contain from 0.1 to 2.5% Mn and
from 0.1 to 1.5% Si. It has been found that modified Cu--Ni--Sn
variants with an Si content of up to 1.5% by weight and an Mn
content of up to 2.5% by weight can be manufactured with an
improvement in the material properties. Further laboratory tests
have likewise already been carried out in this regard, and have
confirmed the limiting values.
[0021] In this way, the approach of achieving a further improvement
in the wear resistance of Cu--Ni--Sn alloys by the formation of
hard intermetallic phases is pursued. These further hard material
phases involve manganese-nickel silicides. Cu--Ni--Sn alloys per se
already exhibit very good properties with respect to the
low-friction properties, corrosion resistance and relaxation or
resistance at room temperature. The hard phases which are formed
also reduce the susceptibility to adhesion in the mixed friction
range and further increase the thermal stability and the ductility
at higher temperatures.
[0022] By combining the structural components contributing to the
wear resistance in conjunction with the spinoidally demixing alloy
of the Cu--Ni--Sn system, surprisingly on the one hand it is
possible to reduce the run-in behavior at the start of stress due
to wear, and on the other hand such a Cu--Ni--Sn--Mn--Si material
turns out to be just as thermally stable as well as sufficiently
ductile.
[0023] The multicomponent copper alloy may advantageously contain
from 0.1 to 1.6% Mn and from 0.1 to 0.7% Si. In particular, it has
been established that it is in fact possible to manufacture without
problems in terms of manufacturing technology with an Si content of
up to 0.7% by weight and an Mn content of up to 1.6% by weight.
With high silicon and manganese contents, corresponding adaptations
should be carried out for the casting parameters in the context of
standard precautions.
[0024] The multicomponent copper alloy may advantageously undergo
at least one heat treatment at from 300 to 500.degree. C. The
material is thereby strengthened owing to the spinoidal demixing
which takes place.
[0025] In a preferred configuration of the invention, the
multicomponent copper alloy may undergo at least one heat treatment
at from 600 to 800.degree. C. The heat treatment in this range
leads to homogenization, which makes the material more ductile.
[0026] In a particularly preferred configuration of the invention,
the multicomponent copper alloy may undergo a combination of at
least one solution anneal at from 600 to 800.degree. C. and at
least one age hardening at from 300 to 500.degree. C. The material
is thereby strengthened owing to the spinoidal demixing which takes
place. The heat treatment in this range leads to homogenization,
which makes the material softer. Owing to a homogenizing anneal and
the hardening of the material during age hardening or rolling, the
material properties of the multicomponent copper alloy can be
adapted optimally to the respective task.
[0027] In another preferred configuration, the multicomponent
copper alloy may be employed for friction-bearing elements or jack
connectors.
[0028] Exemplary embodiments of the invention will be explained in
more detail with the aid of the following example and the scanning
electron microscope image shown in FIG. 1.
EXAMPLE
[0029] In series of tests, blocks with various Mn--Si ratios were
cast and subsequently cold-processed further. The alloy variants
studied are collated in Table 1. The cast blocks were homogenized
in the temperature range of between 700 and 800.degree. C. and then
milled.
[0030] Strips with thicknesses of between 2.5 and 2.85 mm were
produced by a plurality of cold forming operations and intermediate
anneals. The strips were cold-rolled and annealed in the
temperature range of between 700 and 800.degree. C., in order to
achieve sufficient cold forming properties.
TABLE-US-00001 TABLE 1 Cu--Ni-- Cu Ni Sn Mn Si Sn + Mn + Si [wt. %]
[wt. %] [wt. %] [wt. %] [wt. %] Variant 1 remainder 5.6-6.0 5.2-5.6
1.7-2.0 0.2-0.3 Variant 2 remainder 5.6-6.0 5.2-5.6 1.3-1.6 0.2-0.3
Variant 3 remainder 5.6-6.0 5.2-5.6 1.3-1.6 0.5-0.7 Variant 4
remainder 5.6-6.0 5.2-5.6 0.8-1.0 0.1-0.3 Variant 5 remainder
5.6-6.0 5.2-5.6 0.8-1.0 0.3-0.5 Variant 6 remainder 5.6-6.0 5.2-5.6
0.4-0.6 0.4-0.6 Variant 7 remainder 5.6-6.0 5.2-5.6 0.9-1.1 0.9-1.1
Variant 8 remainder 5.6-6.0 5.2-5.6 1.8-2.1 0.5-0.5 Variant 9
remainder 5.6-6.0 5.2-5.6 1.8-2.1 0.9-1.1
[0031] According to expectation, it was confirmed that the cold
formability of the Cu--Ni--Sn alloy modified with silicides is
somewhat less than in the case of a Cu--Ni--Sn alloy without
further silicide phases.
[0032] Such strips may be combined in a further method step to form
a firm material composite by roll-cladding methods. Cu--Ni--Sn
alloys modified with suicides have a much lower coefficient of
friction compared with the silicide-free variant. The alloy
according to the invention is therefore suitable in particular as a
primary material for use as a friction-bearing element (bushings,
thrust rings, etc.) in the respective automotive field for motors,
transmissions and hydraulics.
[0033] FIG. 1 shows a scanning electron microscope image of the
surface of a multicomponent copper alloy. The relatively finely
distributed manganese-nickel silicides 2, which are embedded in the
alloy matrix 1, may be seen clearly. These silicides are already
formed in the melt as an initial precipitate in a temperature range
around 1100.degree. C. With a suitable choice of the melt
composition, the available silicon and manganese precipitates with
a nickel component present in excess to form the silicide. The
nickel component thereby consumed in the silicide may
correspondingly be taken into account for the subsequent formation
of the matrix by a higher nickel component in the melt.
[0034] The composition of the silicides need not necessarily
correspond to a predetermined stoichiometry. Depending on the
process management, and in particular determined by the cooling
rate, ternary intermetallic phases precipitate in the form of
silicides of the (Mn,Ni).sub.xSi type, which lie in the range
between the limiting-case binary phases Mn.sub.5Si.sub.3 and
Ni.sub.2Si.
[0035] The mechanical properties of strips of the multicomponent
copper alloy containing silicides in the rolling-hardened state had
a tensile strength Rm of 560 MPa and a yield point of 480 MPa with
an elongation at break A5 of 25%. The hardness HB was about
176.
[0036] After age hardening the strips, a tensile strength Rm of 715
MPa and a yield point Rp.sub.0.2 of 630 MPa with an elongation at
break A.sub.5 of 17% were found. The hardness HB was about 235.
[0037] FIG. 2 shows a diagram with measurement values of the
elongation at break A.sub.5 for multicomponent copper alloys
according to the invention with silicide phases having been formed
(curves D and E) and conventional multicomponent copper alloys of
the generic type (curves A, B, C) without silicide phases. The
different values of elongation at break at room temperature are
attributable to a different age hardening temperature in the range
of between 300 and 500.degree. C. With temperatures beyond about
250.degree. C., the value for the elongation at break A.sub.5 falls
below 10% for all samples in which no silicide phases are formed.
Only in alloys according to the invention does this value remain
significantly more than 10% throughout the temperature range from
room temperature to 400.degree. C. In the present case, it even
remains above 15%. The alloy according to the invention is
therefore much more ductile than the previously known comparable
alloys without manganese and silicon.
* * * * *