U.S. patent application number 10/451143 was filed with the patent office on 2004-06-17 for cu-base amorphous alloy.
Invention is credited to Inoue, Akihisa, Zhang, Tao, Zhang, Wei.
Application Number | 20040112475 10/451143 |
Document ID | / |
Family ID | 26606791 |
Filed Date | 2004-06-17 |
United States Patent
Application |
20040112475 |
Kind Code |
A1 |
Inoue, Akihisa ; et
al. |
June 17, 2004 |
Cu-base amorphous alloy
Abstract
The present invention provides Cu-base amorphous alloys
comprising an amorphous phase of 90% or more by volume fraction.
The amorphous phase has a composition represented by the formula:
Cu.sub.100-a-b(Zr+Hf).sub.a- Ti.sub.b or
Cu.sub.100-a-b-c-d(Zr+Hf).sub.aTi.sub.bM.sub.cT.sub.d, wherein M is
one or more elements selected from the group consisting of Fe, Cr,
Mn, Ni, Co, Nb, Mo, W, Sn, Al, Ta and rare earth elements, T is one
or more elements selected from the group consisting of Ag, Pd, Pt
and Au, and a, b, c and d are atomic percentages falling within the
following ranges: 5<a.ltoreq.55, 0.ltoreq.b.ltoreq.45,
30<a+b.ltoreq.60, 0.5.ltoreq.c.ltoreq.5, 0.ltoreq.d.ltoreq.10.
The Cu-base amorphous alloy has a high glass-forming ability as
well as excellent mechanical properties and formability, and can be
formed as a rod or plate material with a diameter or thickness of 1
mm or more and an amorphous phase of 90% or more by volume
fraction, through a metal mold casting process.
Inventors: |
Inoue, Akihisa; (Miyagi,
JP) ; Zhang, Wei; (Miyagi, JP) ; Zhang,
Tao; (Miyagi, JP) |
Correspondence
Address: |
WESTERMAN, HATTORI, DANIELS & ADRIAN, LLP
1250 CONNECTICUT AVENUE, NW
SUITE 700
WASHINGTON
DC
20036
US
|
Family ID: |
26606791 |
Appl. No.: |
10/451143 |
Filed: |
December 1, 2003 |
PCT Filed: |
November 28, 2001 |
PCT NO: |
PCT/JP01/10410 |
Current U.S.
Class: |
148/403 ;
420/492 |
Current CPC
Class: |
C22C 45/001 20130101;
C22C 1/002 20130101 |
Class at
Publication: |
148/403 ;
420/492 |
International
Class: |
C22C 009/00; C22C
045/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 27, 2000 |
JP |
2000-397007 |
Aug 30, 2001 |
JP |
2001-262438 |
Claims
What is claimed is:
1. A Cu-base amorphous alloy comprising an amorphous phase of 90%
or more by volume fraction, said amorphous phase having a
composition represented by the following formula:
Cu.sub.100-a-b(Zr+Hf).sub.aTi.sub.b , wherein a and b are atomic
percentages falling within the following ranges: 5<a.ltoreq.55
0.ltoreq.b.ltoreq.45 30<a+b.ltoreq.60
2. A Cu-base amorphous alloy comprising an amorphous phase of 90%
or more by volume fraction, said amorphous phase having a
composition represented by the following formula:
Cu.sub.100-a-b(Zr+Hf).sub.aTi.sub.b , wherein a and b are atomic
percentages falling within the following ranges: 10<a.ltoreq.40
5.ltoreq.b.ltoreq.30 35.ltoreq.a+b.ltoreq.50
3. A Cu-base amorphous alloy comprising an amorphous phase of 90%
or more by volume fraction, said amorphous phase having a
composition represented by the following formula:
Cu.sub.100-a-b-c-d(Zr+Hf).sub.aTi.sub.bM.sub.cT- .sub.d , wherein M
is one or more elements selected from the group consisting of Fe,
Cr, Mn, Ni, Co, Nb, Mo, W, Sn, Al, Ta and rare earth elements, T is
one or more elements selected from the group consisting of Ag, Pd,
Pt and Au, and a, b, c and d are atomic percentages falling within
the following ranges: 5<a.ltoreq.55 0.ltoreq.b.ltoreq.45
30<a+b.ltoreq.60 0.5.ltoreq.c.ltoreq.5 0.ltoreq.d.ltoreq.10
4. A Cu-base amorphous alloy comprising an amorphous phase of 90%
or more by volume fraction, said amorphous phase having a
composition represented by the following formula:
Cu.sub.100-a-b-c-d(Zr+Hf).sub.aTi.sub.bM.sub.cT- .sub.d, wherein M
is one or more elements selected from the group consisting of Fe,
Cr, Mn, Ni, Co, Nb, Mo, W, Sn, Al, Ta and rare earth elements, T is
one or more elements selected from the group consisting of Ag, Pd,
Pt and Au, and a, b, c and d are atomic percentages falling within
the following ranges: 10<a.ltoreq.40 5.ltoreq.b.ltoreq.30
35.ltoreq.a+b.ltoreq.50 0.5.ltoreq.c.ltoreq.5
0.ltoreq.d.ltoreq.10
5. The Cu-base amorphous alloy as defined in either one of claims 1
to 4, which has a supercooled liquid region with a temperature
interval .DELTA.Tx of 25 K or more, said temperature interval being
represented by the following formula: .DELTA.Tx=Tx-Tg , wherein Tx
is a crystallization temperature of said alloy, and Tg is a glass
transition temperature of said alloy.
6. The Cu-base amorphous alloy as defined in either one of claims 1
to 5, which has a reduced glass transition temperature of 0.56 or
more, said reduced-glass-transition temperature being represented
by the following formula: Tg/Tm , wherein Tg is a glass transition
temperature of said alloy, and Tm is a melting temperature of said
alloy.
7. The Cu-base amorphous alloy as defined in either one of claims 1
to 6, which is formed as a rod or plate material having a diameter
or thickness of 1 mm or more and an amorphous phase of 90% or more
by volume fraction, through a metal mold casting process.
8. The Cu-base amorphous alloy as defined in either one of claims 1
to 7, which has a compressive fracture strength of 1800 MPa or
more, an elongation of 1.5% or more, and a Young's modulus of 100
GPa or more.
Description
TECHNICAL FIELD
[0001] The present invention relates to a Cu-base amorphous alloy
having a high glass-forming ability as well as excellent mechanical
properties and formability.
BACKGROUND ART
[0002] It is well known that an alloy in its molten state can be
rapidly cooled or quenched to obtain an amorphous solid in various
forms, such as thin strip, filament or powder/particle. An
amorphous alloy thin-strip or powder can be prepared through
various processes, such as a single-roll process, a twin-roll
process, an in-rotating liquid spinning process and an atomization
process, which can provide a high quenching rate. Heretofore, a
number of Fe, Ti, Co, Zr, Ni, Pd or Cu-base amorphous alloys have
been developed, and their specific properties such as excellent
mechanical properties and high corrosion resistance have been
clarified.
[0003] In regard to Cu-base amorphous alloys related to the present
invention, researches have been mainly made on binary alloys such
as Cu-Ti and Cu-Zr, or ternary alloys such as Cu-Ni-Zr, Cu-Ag-RE,
Cu-Ni-P, Cu-Ag-P, Cu-Mg-RE and Cu-(Zr, RE, Ti)-(Al, Mg, Ni)
(Japanese Patent Laid-Open Publication Nos. H07-41918, H07-173556,
H09-59750 and H11-61289; Sic. Rep. RITU. A42 (1996) 1343-1349; Sic.
Rep. RITU. A28 (1980) 225-230; Mater. Sic. Eng. A181-182 (1994)
1383-1392; Mater. Trans. JIM, 37 (1996) 359-362).
[0004] While the above Cu-base amorphous alloys have been
researched based largely on thin-strip samples prepared through the
aforementioned single-roll/liquid quenching process, research and
development on Cu-base bulk amorphous alloys for practical use, or
Cu-base bulk amorphous alloys excellent in glass-forming ability,
has made few advance.
DISCLOSURE OF THE INVENTION
[0005] It is known that an amorphous alloy undergoing a glass
transition with a wide supercooled liquid region and having a high
reduced-glass-transition temperature (Tg/Tm) exhibits an excellent
stability against crystallization and a high glass-forming ability.
The alloy having such a high glass-forming ability can be formed as
a bulk amorphous alloy through a metal mold casting process. It is
also known that when a specific amorphous alloy is heated, the
viscosity of the amorphous alloy is sharply lowered during
transition to the supercooled liquid state before
crystallization.
[0006] Such an amorphous alloy can be formed in an arbitrary shape
through a closed forging process or the like by taking advantage of
the lowered viscosity in the supercooled liquid state. Thus, it can
be said that an alloy having a wide supercooled liquid region and a
high reduced-glass-transition temperature (Tg/Tm) exhibits a high
glass-forming ability and an excellent formability.
[0007] The conventional Cu-base amorphous alloys have a poor
glass-forming ability, and have been able to be formed only in
limited forms, such as thin strip, powder and thin line, through a
liquid quenching process. In addition, they have no stability at
high temperature, and have difficulty in being converted into a
final product with a desired shape, resulting in their quite
limited industrial applications.
[0008] In view of the above circumstance, it is an object of the
present invention to provide a Cu-base amorphous alloy having a
high glass-forming ability as well as excellent mechanical
properties and formability.
[0009] Through various researches on the optimal composition of
Cu-base alloy for achieving the above object, the inventors found
that a Cu-base alloy having a specific composition containing Zr
and/or Hf can be molten and then rapidly solidified from the liquid
state to obtain a Cu-base amorphous alloy having a high
glass-forming ability as well as excellent mechanical properties
and formability, such as a rod-shaped (or plate-shaped) amorphous-
phase material with 1 mm or more of diameter (or thickness). Based
on this knowledge, the inventors have completed the present
invention.
[0010] Specifically, according to a first aspect of the present
invention, there is provided a Cu-base amorphous alloy comprising
an amorphous phase of 90% or more by volume fraction. The amorphous
phase has a composition represented by the following formula:
Cu.sup.100-a-b(Zr+Hf).sub.aTi.sub.b
[0011] , wherein a and b are atomic percentages falling within the
following ranges: 5<a.ltoreq.55, 0.ltoreq.b.ltoreq.45,
30<a+b.ltoreq.60 . In this formula, (Zr+Hf) means Zr and/or
Hf.
[0012] According to a second aspect of the present invention, there
is provided a Cu-base amorphous alloy comprising an amorphous phase
of 90% or more by volume fraction. The amorphous phase has a
composition represented by the following formula:
Cu.sub.100-a-b(Zr+Hf).sub.aTi.sub.b
[0013] wherein a and b are atomic percentages falling within the
following ranges: 10<a.ltoreq.40, 5.ltoreq.b.ltoreq.30,
35.ltoreq.a+b.ltoreq.50.
[0014] According to a third aspect of the present invention, there
is provided a Cu-base amorphous alloy comprising an amorphous phase
of 90% or more by volume fraction. The amorphous phase has a
composition represented by the following formula:
Cu.sub.100-a-b-c-d(Zr+Hf).sub.aTi.sub.bM.sub.cT.sub.d
[0015] , wherein M is one or more elements selected from the group
consisting of Fe, Cr, Mn, Ni, Co, Nb, Mo, W, Sn, Al, Ta and rare
earth elements, T is one or more elements selected from the group
consisting of Ag, Pd, Pt and Au, and a, b, c and d are atomic
percentages falling within the following ranges: 5<a.ltoreq.55,
0.ltoreq.b.ltoreq.45, 30<a+b.ltoreq.60, 0.5.ltoreq.c.ltoreq.5,
0.ltoreq.d.ltoreq.10.
[0016] According to a fourth aspect of the present invention, there
is provided a Cu-base amorphous alloy comprising an amorphous phase
of 90% or more by volume fraction. The amorphous phase has a
composition represented by the following formula:
Cu.sub.100-a-b-c-d(Zr+Hf).sub.aTi.sub.bM.sub.cT.sub.d
[0017] , wherein M is one or more elements selected from the group
consisting of Fe, Cr, Mn, Ni, Co, Nb, Mo, W, Sn, Al, Ta and rare
earth elements, T is one or more elements selected from the group
consisting of Ag, Pd, Pt and Au, and a, b, c and d are atomic
percentages falling within the following ranges: 10<a.ltoreq.40,
5.ltoreq.b.ltoreq.30, 35.ltoreq.a+b.ltoreq.50,
0.5.ltoreq.c.ltoreq.5, 0.ltoreq.d.ltoreq.10.
[0018] The above Cu-base amorphous alloys of the present invention
may have a supercooled liquid region with a temperature interval
.DELTA.Tx of 25 K or more. The temperature interval is represented
by the following formula: .DELTA.Tx=Tx-Tg, wherein Tx is a
crystallization temperature of the alloy, and Tg is a glass
transition temperature of the alloy.
[0019] The Cu-base amorphous alloys of the present invention may
have a reduced glass transition temperature of 0.56 or more. The
reduced glass transition temperature is represented by the
following formula: Tg/Tm, wherein Tg is a glass transition
temperature of the alloy, and Tm is a melting temperature of the
alloy.
[0020] The Cu-base amorphous alloys of the present invention may be
formed as a rod or plate material having a diameter or thickness of
1 mm or more and an amorphous phase of 90% or more by volume
fraction, through a metal mold casting process.
[0021] The Cu-base amorphous alloys of the present invention may
have a compressive fracture strength of 1800 MPa or more, an
elongation of 1.5% or more, and a Young's modulus of 100 GPa or
more.
[0022] The term "supercooled liquid region" herein is defined by
the difference between a glass transition temperature of the alloy
and a crystallization temperature (or an initiation temperature of
crystallization) of the alloy, which are obtained from a
differential scanning calorimetric analysis performed at a heating
rate of 40 K/minute. The "supercooled liquid temperature region" is
a numerical value indicative of resistibility against
crystallization which is equivalent to thermal stability of
amorphous state, glass-forming ability or formability. The alloys
of the present invention have a supercooled liquid temperature
region .DELTA.Tx of 25 K or more.
[0023] The term "reduced glass transition temperature" herein is
defined by a ratio of the glass transition temperature (Tg) to a
melting temperature (Tm) of the alloy which is obtained from a
differential scanning calorimetric analysis (DTA) performed at a
heating rate of 5 K/minute. The "reduced glass transition
temperature" is a numerical value indicative of the glass-forming
ability.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] FIG. 1 is a graph showing a composition range of Cu-Zr-Ti
ternary alloys capable of forming a bulk amorphous material and the
critical thickness (unit: mm) of the bulk amorphous materials.
[0025] FIG. 2 is a graph showing a stress-strain curve in a
compression test of a Cu.sub.60Zr.sub.20Ti.sub.20 bulk amorphous
alloy having a diameter of 2 mm.
BEST MODE FOR CARRYING OUT THE INVENTION
[0026] One embodiment of the present invention will now be
described.
[0027] In a Cu-base amorphous alloy of the present invention, Zr
and/or Hf are basic elements for forming an amorphous material. The
content of Zr and/or Hf is set in the range of greater than 5
atomic % up to 55 atomic %, preferably in the range of 10 to 40
atomic %. If the content of Zr and/or Hf is reduced to 5 atomic %
or less or increased to greater than 55 atomic %, the supercooled
liquid region .DELTA.Tx and the reduced glass transition
temperature Tg/Tm will be reduced, resulting in deteriorated
glass-forming ability.
[0028] Element Ti is effective to enhance the glass-forming ability
to a large degree. However, if the content of Ti is increased to
greater than 45 atomic %, the supercooled liquid region .DELTA.Tx
and the reduced glass transition temperature Tg/Tm will be reduced,
resulting in deteriorated glass-forming ability. Thus, the content
of Ti is set in the range of 0 to 45 atomic %, preferably 5 to 30
atomic %.
[0029] The total of the content of Zr and/or Hf and the content of
Ti is set in the range of greater than 30 atomic % up to 60 atomic
%. If the total content of these elements is reduced to 30 atomic %
or increased to greater than 60 atomic %, the glass-forming ability
will be deteriorated, and no bulk material can be obtained.
Preferably, the total content is set in the range of 35 to 50
atomic %.
[0030] Cu of up to 10 atomic % may be substituted with one or more
element selected from the group consisting of Ag, Pd, Au and Pt.
This substitution can slightly increase the temperature interval of
the supercooled liquid region. If greater than 10 atomic % of Cu is
substituted, the supercooled liquid region will be reduced to less
than 25 K, resulting in deteriorated glass-forming ability.
[0031] While a small amount of one or more elements selected from
the group consisting of Fe, Cr, Mn, Ni, Co, Nb, Mo, W, Sn, Al, Ta
and rare earth elements (Y, Gd, Tb, Dy, Sc, La, Ce, Pr, Nd, Sm, Eu
and Ho) may be effectively added to provide an enhanced mechanical
strength, the glass-forming ability is deteriorated as the addition
of these elements is increased. Thus, the content of these element
is preferably set in the range of 0.5 to 5 atomic %.
[0032] FIG. 1 shows a composition range of Cu-Zr-Ti ternary alloys
capable of forming a bulk amorphous material and the critical
thickness of the bulk amorphous materials. The composition range
capable of forming a bulk amorphous material (having a diameter of
1 mm or more) is shown by the solid line. The numeral in the circle
indicates the maximum thickness (unit:mm) of the bulk amorphous
materials to be formed in the bulk amorphous materials. FIG. 2
shows a stress-strain curve in a compression test of a
Cu.sub.60Zr.sub.20Ti.sub.20 bulk amorphous alloy. This alloy has a
compressive fracture strength of about 2000 MPa, an elongation of
2.5%, and a Young's modulus of 122 GPa.
[0033] The Cu-base amorphous alloy of the present invention can be
cooled and solidified from its molten state through various
processes, such as a single-roll process, a twin-roll process, an
in-rotating liquid spinning process and an atomization process, to
provide an amorphous solid in various forms, such as thin strip,
filament or powder/particle. The Cu-base amorphous alloys of the
present invention can also be formed as a bulk amorphous alloy
having an arbitrary shape through not only the above conventional
processes but also a process of filling a molten metal in a metal
mold and casting therein by taking advantage of its high
glass-forming ability.
[0034] For example, in a typical metal mold casting process, a
mother alloy prepared to have the alloy composition of the present
invention is molten in a silica tube under argon atmosphere. Then,
the molten alloy is filled in a copper mold at an injection
pressure of 0.5 to 1.5 kg .multidot. f/cm.sup.2, and solidified so
as to obtain an amorphous alloy ingot. Alternatively, any other
suitable method such as a die-casting process or a squeeze-casting
process may be used.
EXAMPLE
[0035] Examples of the present invention will be described below.
For each of materials having alloy compositions as shown in Table 1
(Inventive Examples 1 to 17 and Comparative Examples 1 to 4), a
corresponding mother alloy was molten through an arc-melting
process, and then a thin-strip sample of about 20 .mu.m thickness
was prepared through a single-roll/liquid quenching process. Then,
the glass transition temperature (Tg) and the crystallization
temperature (Tx) of the thin-strip sample were measured by a
differential scanning calorimeter (DSC). Based on these measured
values, the supercooled liquid region .DELTA.Tx (=Tx-Tg) of the
thin-strip sample was calculated. The melting temperature (Tm) of
the sample was also measured by a differential scanning
calorimetric analysis (DTA). Then, the reduced glass transition
temperature (Tg/Tm) of the sample was calculated from the obtained
glass transition temperature and the melting temperature.
[0036] Further, a rod-shaped sample of 1 mm diameter was prepared
for each of the above materials, and the amorphous phase in the
rod-shaped sample was determined through an X-ray diffraction
method. The volume fraction (Vf-amo.) of the amorphous phase in the
sample was also evaluated by comparing the calorific value of the
sample during crystallization with that of a completely vitrified
thin strip of about 20 .mu.m thickness, by use of DSC. These
evaluation results are shown in Table 1. Further, a compression
test piece was prepared for each of the above materials, and the
test piece was subjected to a compression test using an
Instron-type testing machine to evaluate the compressive fracture
strength (.sigma. f), the Young's modulus (E) and the elongation
(.epsilon.) of the test piece. The Vickers hardness (Hv) was also
measured. These evaluation results are shown in Table 2.
1 TABLE 1 Alloy Composition Tg Tx Tx - Tg Vf-Amo. (at %) (K) (K)
(K) Tg/Tm (%) Inventive Example 1 Cu.sub.65Zr.sub.25Ti.sub.10 726
765 39 0.58 100 Inventive Example 2 Cu.sub.60Zr.sub.40 722 777 55
0.60 91 Inventive Example 3 Cu.sub.60Zr.sub.30Ti.sub.10 713 750 37
0.62 100 Inventive Example 4 Cu.sub.60Zr.sub.20Ti.sub.20 708 743 35
0.63 100 Inventive Example 5 Cu.sub.60Zr.sub.10Ti.sub.30 688 719 31
0.58 100 Inventive Example 6 Cu.sub.55Zr.sub.35Ti.sub.10 680 727 47
0.59 100 Inventive Example 7 Cu.sub.65Hf.sub.25Ti.sub.10 760 797 37
0.57 100 Inventive Example 8 Cu.sub.60Hf.sub.30Ti.sub.10 747 814 67
0.61 100 Inventive Example 9 Cu.sub.60Hf.sub.20Ti.sub.20 730 768 38
0.62 100 Inventive Example 10 Cu.sub.60Hf.sub.10Ti.sub.30 696 731
35 0.59 100 Inventive Example 11 Cu.sub.55Hf.sub.30Ti.sub.15 727
785 58 0.59 100 Inventive Example 12
Cu.sub.60Zr.sub.15Hf.sub.15Ti.sub- .10 729 784 55 0.61 100
Inventive Example 13 Cu.sub.60Zr.sub.10Hf.sub.10Ti.sub.20 716 753
37 0.63 100 Inventive Example 14
Cu.sub.60Zr.sub.28Ti.sub.10Nb.sub.2 724 757 33 0.59 95 Inventive
Example 15 Cu.sub.60Zr.sub.27Ti.sub.10Sn.sub.3 837 877 40 0.61 95
Inventive Example 16 Cu.sub.60Zr.sub.27Ti.sub.10Ni.sub.3 719 754 35
0.60 94 Inventive Example 17 Cu.sub.60Zr.sub.25Ti.sub.10Ni- .sub.5
708 749 41 0.60 100 Comparative Example 1
Cu.sub.70Zr.sub.20Ti.sub.10 746 50< Comparative Example 2
Cu.sub.70Hf.sub.20Ti.sub.10 771 50< Comparative Example 3
Cu.sub.60Zr.sub.20Ti.sub.10Ni.sub.10 762 50< Comparative Example
4 Cu.sub.60Ti.sub.40 694 50<
[0037] As seen in Table 1, each of the amorphous alloys of
Inventive Examples exhibited a supercooled liquid region .DELTA.Tx
(=Tx-Tg) of 25 K or more and a reduced glass transition temperature
(Tg/Tm) of 0.56 or more, and could be readily formed as an
amorphous alloy rod of 1 mm diameter.
[0038] In contrast, each of the amorphous alloys of Comparative
Examples 1 and 2, in which the total of the content of Zr and/or Hf
and the content of Ti is 30 atomic %, exhibited no glass
transition, and no amorphous alloy rod of 1 mm diameter could be
formed therefrom due to its poor glass-forming ability. The
amorphous alloy of Comparative Example 3, in which the content of
Ni is 10 atomic %, exhibited no glass transition, and no amorphous
alloy rod of 1 mm diameter could be formed therefrom due to its
poor glass-forming ability. While the amorphous alloy of
Comparative Example 4 containing no basic element Zr and/or Hf was
vitrified in the form of a ribbon prepared through a single-roll
process at a high cooling rate, no amorphous alloy rod of 1 mm
diameter could be formed therefrom, and the compression test could
not be conducted.
2 TABLE 2 Alloy Composition .sigma. f E .epsilon. (at %) (MPa)
(GPa) (%) Hv Inventive Example 1 Cu.sub.65Zr.sub.25Ti.sub.10 1970
108 2.0 603 Inventive Example 2 Cu.sub.60Zr.sub.40 1880 102 2.7 555
Inventive Example 3 Cu.sub.60Zr.sub.30Ti.sub.10 2115 124 3.2 504
Inventive Example 4 Cu.sub.60Zr.sub.20Ti.sub.20 2015 140 2.6 556
Inventive Example 5 Cu.sub.60Zr.sub.10Ti.sub.30 2010 135 1.7 576
Inventive Example 6 Cu.sub.55Zr.sub.35Ti.sub.10 1860 112 2.8 567
Inventive Example 7 Cu.sub.65Hf.sub.25Ti.sub.10 2145 142 1.8 698
Inventive Example 8 Cu.sub.60Hf.sub.30Ti.sub.10 2143 134 1.9 592
Inventive Example 9 Cu.sub.60Hf.sub.20Ti.sub.20 2078 135 2.1 620
Inventive Example Cu.sub.60Hf.sub.10Ti.sub.30 2260 126 1.8 650 10
Inventive Example Cu.sub.55Hf.sub.30Ti.sub.15 2175 114 2.0 681 11
Inventive Example Cu.sub.60Zr.sub.15Hf.sub.15Ti.sub.10 2100 121 2.4
640 12 Inventive Example Cu.sub.60Zr.sub.10Hf.sub.10Ti.- sub.20
2110 136 2.2 647 13 Inventive Example
Cu.sub.60Zr.sub.28Ti.sub.10Nb.sub.2 2204 129 2.0 574 14 Inventive
Example Cu.sub.60Zr.sub.27Ti.sub.10Sn.sub.3 2145 125 1.8 519 15
Inventive Example Cu.sub.60Zr.sub.27Ti.sub.10Ni.sub.3 2130 128 2.1
556 16 Inventive Example Cu.sub.60Zr.sub.25Ti.sub.1- 0Ni.sub.5 1915
113 2.4 531 17 Comparative Cu.sub.70Zr.sub.20Ti.sub.10 564 Example
1 Comparative Cu.sub.70Hf.sub.20Ti.sub.10 624 Example 2 Comparative
Cu.sub.60Zr.sub.20Ti.sub.10Ni.sub.10 578 Example 3 Comparative
Cu.sub.60Ti.sub.40 566 Example 4
[0039] As seen in Table 2, each of the amorphous alloys of
Inventive Examples exhibited a compressive fracture strength
(.sigma. f) of 1800 MPa or more, an elongation (.epsilon.) of 1.5%
or more, and a Young's modulus (E) of 100 GPa or more.
[0040] Further, for each of materials having alloy compositions as
shown in Table 3 (Inventive Examples 18 to 32 and Comparative
Examples 5 to 8), a corresponding mother alloy was molten through
an arc-melting process, and then a rod-shaped sample with an
amorphous single phase was prepared through a metal mold casting
process. Then, the critical thickness and the critical diameter of
the rod-shaped sample were measured. A compression test piece was
also prepared for each of the above materials, and the test piece
was subjected to a compression test using an Instron-type testing
machine to evaluate the compressive fracture strength (.sigma. f).
These results are shown in Table 3.
3 TABLE 3 Compressive Fracture Critical Thickness Alloy Composition
Strength (.sigma. f) Critical Diameter* (at %) (MPa) (mm) Inventive
Example 18 Cu.sub.58Zr.sub.20Hf.sub.10Ti.sub.10Gd.sub.2 2000 3
Inventive Example 19 Cu.sub.58Zr.sub.20Hf.sub.10Ti.sub.10Al.sub.2
2200 3 Inventive Example 20
Cu.sub.58Zr.sub.20Hf.sub.10Ti.sub.10Sn.sub.2 2200 4 Inventive
Example 21 Cu.sub.58Zr.sub.20Hf.sub.10Ti.sub.10Ta- .sub.2 2250 4
Inventive Example 22 Cu.sub.58Zr.sub.20Hf.sub.10Ti.su- b.10W.sub.2
2300 3 Inventive Example 23 Cu.sub.60Zr.sub.29Ti.sub.9G- d.sub.2
2150 4 Inventive Example 24 Cu.sub.60Hf.sub.24Ti.sub.14Y.su- b.2
2400 5 Inventive Example 25 Cu.sub.60Hf.sub.24Ti.sub.14Gd.sub.2
2430 3 Inventive Example 26 Cu.sub.58Zr.sub.29Ti.sub.9Fe.sub.2Y.su-
b.2 2000 3 Inventive Example 27
Cu.sub.58Zr.sub.29Ti.sub.9Cr.sub.2G- d.sub.2 2300 3 Inventive
Example 28 Cu.sub.58Hf.sub.24Ti.sub.14Mn.s- ub.2Y.sub.2 2100 2
Inventive Example 29 Cu.sub.58Zr.sub.28Ti.sub.9F-
e.sub.2Y.sub.2Ag.sub.1 2100 3 Inventive Example 30
Cu.sub.58Zr.sub.28Ti.sub.9Cr.sub.2Gd.sub.2Au.sub.1 2100 3 Inventive
Example 31 Cu.sub.58Hf.sub.22Ti.sub.14Mn.sub.2Y.sub.2Pd.sub.2 2210
4 Inventive Example 32 Cu.sub.58Zr.sub.18Hf.sub.10Ti.sub.10Gd-
.sub.2Pt.sub.2 2300 5 Comparative Example 5
Cu.sub.70Zr.sub.20Ti.su- b.10 *0.100 Comparative Example 6
Cu.sub.70Hf.sub.20Ti.sub.10 *0.100 Comparative Example 7
Cu.sub.75Zr.sub.15Ti.sub.10 *0.050 Comparative Example 8
Cu.sub.75Hf.sub.15Ti.sub.10 *0.050
[0041] As seen in Table 3, the critical thickness in Comparative
Examples is 0.1 mm at the highest, whereas Inventive Examples have
a critical thickness of 2 mm or more, and a compressive fracture
strength of 2000 MPa or more. This result verifies that Inventive
Examples added with rare earth elements represented by M in the
aforementioned formula can be formed as an amorphous alloy
excellent in glass-forming ability and mechanical properties.
Industrial Applicability
[0042] As mentioned above, according to the Cu-base amorphous alloy
composition of the present invention, a rod-shaped sample having a
diameter (thickness) of 1 mm or more can be readily prepared
through a metal mold casting process. The amorphous alloy exhibits
a supercooled liquid region of 25 K or more, and has high strength
and Young's modulus. Thus, the present invention can provide a
practically useful Cu-base amorphous alloy having a high
glass-forming ability as well as excellent mechanical properties
and formability.
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