U.S. patent application number 10/537477 was filed with the patent office on 2006-01-19 for ni-based single crystal superalloy.
Invention is credited to Yasuhiro Aoki, Mikiya Arai, Hiroshi Harada, Toshiharu Kobayashi, Yutaka Koizumi, Shoiu Masaki, Tadaharu Yokokawa.
Application Number | 20060011271 10/537477 |
Document ID | / |
Family ID | 32500797 |
Filed Date | 2006-01-19 |
United States Patent
Application |
20060011271 |
Kind Code |
A1 |
Kobayashi; Toshiharu ; et
al. |
January 19, 2006 |
Ni-based single crystal superalloy
Abstract
The object of the present invention is to provide an Ni-based
single crystal super alloy capable of improving strength by
preventing precipitation of a TCP phase at high temperatures. This
object is achieved by an Ni-based single crystal super alloy having
a composition comprising 5.0-7.0 wt % of Al, 4.0-10.0 wt % of Ta,
1.1-4.5 wt % of Mo, 4.0-10.0 wt % of W, 3.1-8.0 wt % of Re, 0-0.50
wt % of Hf, 2.0-5.0 wt % of Cr, 0-9.9 wt % of Co and 4.1-14.0 wt %
of Ru in terms of its weight ratio, with the remainder consisting
of Ni and unavoidable impurities.
Inventors: |
Kobayashi; Toshiharu;
(Ryugasaki-shi, JP) ; Koizumi; Yutaka;
(Ryugasaki-shi, JP) ; Yokokawa; Tadaharu;
(Tsukaba-shi, JP) ; Harada; Hiroshi; (Tsukuba-shi,
JP) ; Aoki; Yasuhiro; (Tokyo, JP) ; Arai;
Mikiya; (Tokyo, JP) ; Masaki; Shoiu; (Tokyo,
JP) |
Correspondence
Address: |
OSTROLENK FABER GERB & SOFFEN
1180 AVENUE OF THE AMERICAS
NEW YORK
NY
100368403
US
|
Family ID: |
32500797 |
Appl. No.: |
10/537477 |
Filed: |
December 5, 2003 |
PCT Filed: |
December 5, 2003 |
PCT NO: |
PCT/JP03/15619 |
371 Date: |
June 3, 2005 |
Current U.S.
Class: |
148/410 ;
148/428 |
Current CPC
Class: |
C22C 19/057
20130101 |
Class at
Publication: |
148/410 ;
148/428 |
International
Class: |
C22C 19/05 20060101
C22C019/05 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 6, 2002 |
JP |
2002-355756 |
Claims
1. An Ni-based single crystal super alloy having a composition
comprising 5.0-7.0 wt % of Al, 4.0-10.0 wt % of Ta, 1.1-4.5 wt % of
Mo, 4.0-10.0 wt % of W, 3.1-8.0 wt % of Re, 0-0.50 wt % of Hf,
2.0-5.0 wt % of Cr, 0-9.9 wt % of Co and 4.1-14.0 wt % of Ru in
terms of its weight ratio, with the remainder consisting of Ni and
unavoidable impurities.
2. An Ni-based single crystal super alloy having a composition
comprising 5.0-7.0 wt % of Al, 4.0-6.0 wt % of Ta, 1.1-4.5 wt % of
Mo, 4.0-10.0 wt % of W, 3.1-8.0 wt % of Re, 0-0.50 wt % of Hf,
2.0-5.0 wt % of Cr, 0-9.9 wt % of Co, and 4.1-14.0 wt % of Ru in
terms of weight ratio, with the remainder consisting of Ni and
unavoidable impurities.
3. An Ni-based single crystal super alloy having a composition
comprising 5.0-7.0 wt % of Al, 4.0-6.0 wt % of Ta, 2.9-4.5 wt % of
Mo, 4.0-10.0 wt % of W, 3.1-8.0 wt % of Re, 0-0.50 wt % of Hf,
2.0-5.0 wt % of Cr, 0-9.9 wt % of Co and 4.1-14.0 wt % of Ru in
terms of weight ratio, with the remainder consisting of Ni and
unavoidable impurities.
4. An Ni-based single crystal super alloy according to claim 1
having a composition comprising 5.9 wt % of Al, 5.9 wt % of Ta, 3.9
wt % of Mo, 5.9 wt % of W, 4.9 wt % of Re, 0.10 wt % of Hf, 2.9 wt
% of Cr, 5.9 wt % of Co and 5.0 wt % of Ru in terms of weight
ratio, with the remainder consisting of Ni and unavoidable
impurities.
5. An Ni-based single crystal super alloy according to claim 1
having a composition comprising 5.8 wt % of Al, 5.6 wt % of Ta, 3.1
wt % of Mo, 5.8 wt % of W, 4.9 wt % of Re, 0.10 wt % of Hf, 2.9 wt
% of Cr, 5.8 wt % of Co and 5.0 wt % of Ru in terms of weight
ratio, with the remainder consisting of Ni and unavoidable
impurities.
6. An Ni-based single crystal super alloy according to claim 1
having a composition comprising 5.8 wt % of Al, 5.8 wt % of Ta, 3.9
wt % of Mo, 5.8 wt % of W, 4.9 wt % of Re, 0.10 wt % of Hf, 2.9 wt
% of Cr, 5.8 wt % of Co and 6.0 wt % of Ru in terms of weight
ratio, with the remainder consisting of Ni and unavoidable
impurities.
7. An Ni-based single crystal super alloy according to claim 1
further comprising 0-2.0 wt % of Ti in terms of weight ratio.
8. An Ni-based single crystal super alloy according to claim 1
further comprising 0-4.0 wt % of Nb in terms of weight ratio.
9. An Ni-based single crystal super alloy according to claim 1
further comprising at least one of elements selected from B, C, Si,
Y, La, Ce, V and Zr.
10. An Ni-based single crystal super alloy according to claim 9
having a composition comprising 0.05 wt % or less of B, 0.15 wt %
or less of C, 0.1 wt % or less of Si, 0.1 wt % or less of Y, 0.1 wt
% or less of La, 0.1 wt % or less of Ce, 1 wt % or less of V and
0.1 wt % or less of Zr in terms of weight ratio.
11. An Ni-based single crystal super alloy according to claim 1
having a composition comprising 5.0-7.0 wt % of Al, 4.0-10.0 wt %
of Ta, 1.1-4.5 wt % of Mo, 4.0-10.0 wt % of W, 3.1-8.0 wt % of Re,
0-0.50 wt % of Hf, 2.0-5.0 wt % of Cr, 0-9.9 wt % of Co, 10.0-14.0
wt % of Ru, 4.0 wt % or less of Nb, 2.0 wt % or less of Ti, 0.05 wt
% or less of B, 0.15 wt % or less of C, 0.1 wt % or less of Si, 0.1
wt % or less of Y, 0.1 wt % or less of La, 0.1 wt % or less of Ce,
1 wt % or less of V and 0.1 wt % or less of Zr.
12. An Ni-based single crystal super alloy according to claim 1
having a composition comprising 5.8-7.0 wt % of Al, 4.0-5.6 wt % of
Ta, 3.3-4.5 wt % of Mo, 4.0-10.0 wt % of W, 3.1-8.0 wt % of Re,
0-0.50 wt % of Hf, 2.9-4.3 wt % of Cr, 0-9.9 wt % of Co, 4.1-14.0
wt % of Ru, 4.0 wt % or less of Nb, 2.0 wt % or less of Ti, 0.05 wt
% or less of B, 0.15 wt % or less of C, 0.1 wt % or less of Si, 0.1
wt % or less of Y, 0.1 wt % or less of La, 0.1 wt % or less of Ce,
1 wt % or less of V and 0.1 wt % or less of Zr.
13. An Ni-based single crystal super alloy according to claim 1
having a composition comprising 5.0-7.0 wt % of Al, 4.0-10.0 wt %
of Ta, 1.1-4.5 wt % of Mo, 4.0-10.0 wt % of W, 3.1-8.0 wt % of Re,
0-0.50 wt % of Hf, 2.9-5.0 wt % of Cr, 0-9.9 wt % of Co, 6.5-14.0
wt % of Ru, 4.0 wt % or less of Nb, 2.0 wt % or less of Ti, 0.05 wt
% or less of B, 0.15 wt % or less of C, 0.1 wt % or less of Si, 0.1
wt % or less of Y, 0.1 wt % or less of La, 0.1 wt % or less of Ce,
1 wt % or less of V and 0.1 wt % or less of Zr.
14. An Ni-based single crystal super alloy according to claim 1
having a composition comprising 5.0-7.0 wt % of Al, 4.0-6.0 wt % of
Ta, 3.3-4.5 wt % of Mo, 4.0-10.0 wt % of W, 3.1-8.0 wt % of Re,
0-0.50 wt % of Hf, 2.0-5.0 wt % of Cr, 0-9.9 wt % of Co, 4.1-14.0
wt % of Ru, 4.0 wt % or less of Nb, 2.0 wt % or less of Ti, 0.05 wt
% or less of B, 0.15 wt % or less of C, 0.1 wt % or less of Si, 0.1
wt % or less of Y, 0.1 wt % or less of La, 0.1 wt % or less of Ce,
1 wt % or less of V and 0.1 wt % or less of Zr.
15. An Ni-based single crystal super alloy according to claim 1
having a composition comprising 5.0-7.0 wt % of Al, 4.0-5.6 wt % of
Ta, 3.3-4.5 wt % of Mo, 4.0-10.0 wt % of W, 3.1-8.0 wt % of Re,
0-0.50 wt % of Hf, 2.0-5.0 wt % of Cr, 0-9.9 wt % of Co, 4.1-14.0
wt % of Ru, 4.0 wt % or less of Nb, 2.0 wt % or less of Ti, 0.05 wt
% or less of B, 0.15 wt % or less of C, 0.1 wt % or less of Si, 0.1
wt % or less of Y, 0.1 wt % or less of La, 0.1 wt % or less of Ce,
1 wt % or less of V and 0.1 wt % or less of Zr.
16. An Ni-based single crystal super alloy according to claim 1
having a composition comprising 5.0-7.0 wt % of Al, 4.0-10.0 wt %
of Ta, 3.1-4.5 wt % of Mo, 4.0-10.0 wt % of W, 3.1-8.0 wt % of Re,
0-0.50 wt % of Hf, 2.0-5.0 wt % of Cr, 0-9.9 wt % of Co, 4.1-14.0
wt % of Ru, 4.0 wt % or less of Nb, 2.0 wt % or less of Ti, 0.05 wt
% or less of B, 0.15 wt % or less of C, 0.1 wt % or less of Si, 0.1
wt % or less of Y, 0.1 wt % or less of La, 0.1 wt % or less of Ce,
1 wt % or less of V and 0.1 wt % or less of Zr.
17. An Ni-based single crystal super alloy according to claim 1
having a composition comprising 5.8-7.0 wt % of Al, 4.0-10.0 wt %
of Ta, 3.1-4.5 wt % of Mo, 4.0-10.0 wt % of W, 3.1-8.0 wt % of Re,
0-0.50 wt % of Hf, 2.0-5.0 wt % of Cr, 0-9.9 wt % of Co, 4.1-14.0
wt % of Ru, 4.0 wt % or less of Nb, 2.0 wt % or less of Ti, 0.05 wt
% or less of B, 0.15 wt % or less of C, 0.1 wt % or less of Si, 0.1
wt % or less of Y, 0.1 wt % or less of La, 0.1 wt % or less of Ce,
1 wt % or less of V and 0.1 wt % or less of Zr.
18. An Ni-based single crystal super alloy according to claim 1
having a composition comprising 5.0-7.0 wt % of Al, 4.0-10.0 wt %
of Ta, 3.1-4.5 wt % of Mo, 4.0-10.0 wt % of W, 3.1-8.0 wt % of Re,
0-0.50 wt % of Hf, 2.9-4.3 wt % of Cr, 0-9.9 wt % of Co, 4.1-14.0
wt % of Ru, 4.0 wt % or less of Nb, 2.0 wt % or less of Ti, 0.05 wt
% or less of B, 0.15 wt % or less of C, 0.1 wt % or less of Si, 0.1
wt % or less of Y, 0.1 wt % or less of La, 0.1 wt % or less of Ce,
1 wt % or less of V and 0.1 wt % or less of Zr.
19. An Ni-based single crystal super alloy according to claim 1
having a composition comprising 5.0-7.0 wt % of Al, 4.0-10.0 wt %
of Ta+Nb+Ti, 3.3-4.5 wt % of Mo, 4.0-10.0 wt % of W, 3.1-8.0 wt %
of Re, 0-0.50 wt % of Hf, 2.0-5.0 wt % of Cr, 0-9.9 wt % of Co,
4.1-14.0 wt % of Ru, 0.05 wt % or less of B, 0.15 wt % or less of
C, 0.1 wt % or less of Si, 0.1 wt % or less of Y, 0.1 wt % or less
of La, 0.1 wt % or less of Ce, 1 wt % or less of V and 0.1 wt % or
less of Zr.
20. An Ni-based single crystal super alloy according to claim 1
wherein, when lattice constant of matrix is taken to be a1 and
lattice constant of precipitation phase is taken to be a2,
a2.ltoreq.0.999a1.
21. An Ni-based single crystal super alloy according to claim 20
wherein the lattice constant of the precipitation phase a2 is
0.9965 or less of the lattice constant of the matrix a1.
22. An Ni-based single crystal super alloy, wherein lattice
constant of its precipitation phase a2 is 0.9965 or less of lattice
constant of its matrix a1, and having a composition including Re
and Ru, and 2.9-4.5 wt % of Mo.
23. An Ni-based single crystal super alloy, wherein lattice
constant of its precipitation phase a2 is 0.9965 or less of lattice
constant of its matrix a1, and having a composition including
2.9-4.5 wt % of Mo, 3.1-8.0 wt % of Re and 4.1-14.0 wt % of Ru.
24. An Ni-based single crystal super alloy according to claim 1
wherein a dislocation space of the alloy is 40 nm or less.
Description
TECHNICAL FIELD
[0001] The present invention relates to a Ni-based single crystal
super alloy, and more particularly, to a technology employed for
improving the creep characteristics of Ni-based single crystal
super alloy.
BACKGROUND ART
[0002] An example of the typical composition of Ni-based single
crystal super alloy developed for use as a material for moving and
stationary blades subject to high temperatures such as those in
aircraft and gas turbines is shown in Table 1. TABLE-US-00001 TABLE
1 Alloy Elements (wt %) name Al Ti Ta Nb Mo W Re C Zr Hf Cr Co Ru
Ni CMSX-2 6.0 1.0 6.0 -- 1.0 8.0 -- -- -- -- 8.0 5.0 -- Rem CMSX-4
5.6 1.0 6.5 -- 0.6 6.0 3.0 -- -- -- 6.5 9.0 -- Rem ReneN6 6.0 --
7.0 0.3 1.0 6.0 5.0 -- -- 0.2 4.0 13.0 -- Rem CMSX-10K 5.7 0.3 8.4
0.1 0.4 5.5 6.3 -- -- 0.03 2.3 3.3 -- Rem 3B 5.7 0.5 8.0 -- -- 5.5
6.0 0.05 -- 0.15 5.0 12.5 3.0 Rem
[0003] In the above-mentioned Ni-based single crystal super alloys,
after performing solution treatment at a prescribed temperature,
aging treatment is performed to obtain an Ni-based single crystal
super alloy. This alloy is referred to as a so-called precipitation
hardened alloy, and has a from in which the precipitation phase in
the form of a .gamma.' phase is precipitated in a matrix in the
form of a .gamma. phase.
[0004] Among the alloys listed in Table 1, CMSX-2 (Cannon-Muskegon,
U.S. Pat. No. 4,582,548) is a first-generation alloy, CMSX-4
(Cannon-Muskegon, U.S. Pat. No. 4,643,782) is a second-generation
alloy, ReneN6 (General Electric, U.S. Pat. No. 5,455,120) and
CMSX-10K (Canon-Muskegon, U.S. Pat. No. 5,366,695) are
third-generation alloys, and 3B (General Electric, U.S. Pat. No.
5,151,249) is a fourth-generation alloy.
[0005] Although the above-mentioned CMSX-2, which is a
first-generation alloy, and CMSX-4, which is a second-generation
alloy, have comparable creep strength at low temperatures, since a
large amount of the eutectic .gamma.' phase remains following
high-temperature solution treatment, their creep strength is
inferior to third-generation alloys.
[0006] In addition, although the third-generation alloys of ReneN6
and CMSX-10 are alloys designed to have improved creep strength at
high temperatures in comparison with second-generation alloys,
since the composite ratio of Re (5 wt % or more) exceeds the amount
of Re that dissolves into the matrix (.gamma. phase), the excess Re
compounds with other elements and as a result, a so-called TCP
(topologically close packed) phase precipitates at high
temperatures causing the problem of decreased creep strength.
[0007] In addition, making the lattice constant of the
precipitation phase (.gamma.' phase) slightly smaller than the
lattice constant of the matrix (.gamma. phase) is effective in
improving the creep strength of Ni-based single crystal super
alloys. However, since the lattice constant of each phase
fluctuates greatly fluctuated according to the composite ratios of
the composite elements of the alloy, it is difficult to make fine
adjustments in the lattice constant and as a result, there is the
problem of considerable difficulty in improving creep strength.
[0008] In consideration of the above circumstances, the object of
the present invention is to provide a Ni-based single crystal super
alloy that makes it possible to improve strength by preventing
precipitation of the TCP phase at high temperatures.
DISCLOSURE OF INVENTION
[0009] The following constitution is employed in the present
invention in order to achieve the above object.
[0010] The Ni-based single crystal super alloy of the present
invention is characterized by having a composition comprising
5.0-7.0 wt % of Al, 4.0-10.0 wt % of Ta, 1.1-4.5 wt % of Mo,
4.0-10.0 wt % of W, 3.1-8.0 wt % of Re, 0-0.50 wt % of Hf, 2.0-5.0
wt % of Cr, 0-9.9 wt % of Co and 4.1-14.0 wt % of Ru in terms of
its weight ratio, with the remainder consisting of Ni and
unavoidable impurities.
[0011] In addition, the Ni-based single crystal super alloy of the
present invention is characterized by having a composition
comprising 5.0-7.0 wt % of Al, 4.0-6.0 wt % of Ta, 1.1-4.5 wt % of
Mo, 4.0-10.0 wt % of W, 3.1-8.0 wt % of Re, 0-0.50 wt % of Hf,
2.0-5.0 wt % of Cr, 0-9.9 wt % of Co, and 4.1-14.0 wt % of Ru in
terms of weight ratio, with the remainder consisting of Ni and
unavoidable impurities.
[0012] In addition, the Ni-based single crystal super alloy of the
present invention is characterized by having a composition
comprising 5.0-7.0 wt % of Al, 4.0-6.0 wt % of Ta, 2.9-4.5 wt % of
Mo, 4.0-10.0 wt % of W, 3.1-8.0 wt % of Re, 0-0.50 wt % of Hf,
2.0-5.0 wt % of Cr, 0-9.9 wt % of Co and 4.1-14.0 wt % of Ru in
terms of weight ratio, with the remainder consisting of Ni and
unavoidable impurities.
[0013] According to the above Ni-based single crystal super alloy,
precipitation of the TCP phase, which causes a decrease in creep
strength, during use at high temperatures is inhibited by the
addition of Ru. In addition, by setting the composite ratios of
other composite elements within their optimum ranges, the lattice
constant of the matrix (.gamma. phase) and the lattice constant of
the precipitation phase (.gamma.' phase) can be made to have
optimum values. Consequently, strength at high temperatures can be
enhanced. Furthermore, since the composition of Ru is 4.1-14.0 wt
%, precipitation of the TCP phase, which causes a decrease in creep
strength, during use at high temperatures, is inhibited.
[0014] In addition, the Ni-based single crystal super alloy of the
present invention is preferably having a composition comprising 5.9
wt % of Al, 5.9 wt % of Ta, 3.9 wt % of Mo, 5.9 wt % of W, 4.9 wt %
of Re, 0.10 wt % of Hf, 2.9 wt % of Cr, 5.9 wt % of Co and 5.0 wt %
of Ru in terms of weight ratio, with the remainder consisting of Ni
and unavoidable impurities, in the Ni-based single crystal super
alloys previously described.
[0015] According to an Ni-based single crystal super alloy having
this composition, the creep endurance temperature at 137 MPa and
1000 hours can be made to be 1344 K (1071.degree. C.).
[0016] In addition, the Ni-based single crystal super alloy of the
present invention is preferably having a composition comprising 5.8
wt % of Co, 2.9 wt % of Cr, 3.1 wt % of Mo, 5.8 wt % of W, 5.8 wt %
of Al, 5.6 wt % of Ta, 5.0 wt % of Ru, 4.9 wt % of Re and 0.10 wt %
of Hf in terms of weight ratio, with the remainder consisting of Ni
and unavoidable impurities, in the Ni-based single crystal super
alloys previously described.
[0017] According to an Ni-based single crystal super alloy having
this composition, the creep endurance temperature at 137 MPa and
1000 hours can be made to be 1366 K (1093.degree. C.).
[0018] In addition, the Ni-based single crystal super alloy of the
present invention is preferably having a composition comprising 5.8
wt % of Co, 2.9 wt % of Cr, 3.9 wt % of Mo, 5.8 wt % of W, 5.8 wt %
of Al, 5.8 wt % (5.82 wt %) or 5.6 wt % of Ta, 6.0 wt % of Ru, 4.9
wt % of, Re and 0.10 wt % of Hf in terms of weight ratio, with the
remainder consisting of Ni and unavoidable impurities, in the
Ni-based single crystal super alloys previously described.
[0019] According to an Ni-based single crustal super alloy having
this composition, the creep endurance temperature at 137 MPa and
1000 hours can be made to be 1375 K (1102.degree. C.) or 1379 K
(1106.degree. C.).
[0020] Furthermore, 0-2.0 wt % of Ti in terms of weight ratio can
be included in the Ni-based single crystal super alloys previously
described.
[0021] Furthermore, 0-4.0 wt % of Nb in terms of weight ratio can
be included in the Ni-based single crystal alloys previously
described.
[0022] Furthermore, at least one of elements selected from B, C,
Si, Y, La, Ce, V and Zr can be included in the Ni-based single
crystal super alloys previously described.
[0023] In this case, it is preferable that 0.05 wt % or less of B,
0.15 wt % or less of C, 0.1 wt % or less of Si, 0.1 wt % or less of
Y, 0.1 wt % or less of La, 0.1 wt % or less of Ce, 1 wt % or less
of V and 0.1 wt % or less of Zr in terms of weight ratio are
included in the alloys.
[0024] Furthermore, the above described Ni-based single crystal
super alloy is more preferably having a composition comprising
5.0-7.0 wt % of Al, 4.0-10.0 wt % of Ta, 1.1-4.5 wt % of Mo,
4.0-10.0 wt % of W, 3.1-8.0 wt % of Re, 0-0.50 wt % of Hf, 2.0-5.0
wt % of Cr, 0-9.9 wt % of Co, 10.0-14.0 wt % of Ru, 4.0 wt % or
less of Nb, 2.0 wt % or less of Ti, 0.05 wt % or less of B, 0.15 wt
% or less of C, 0.1 wt % or less of Si, 0.1 wt % or less of Y, 0.1
wt % or less of La, 0.1 wt % or less of Ce, 1 wt % or less of V and
0.1 wt % or less of Zr.
[0025] Furthermore, the above described Ni-based single crystal
super alloy is more preferably having a composition comprising
5.8-7.0 wt % of Al, 4.0-5.6 wt % of Ta, 3.3-4.5 wt % of Mo,
4.0-10.0 wt % of W, 3.1-8.0 wt % of Re, 0-0.50 wt % of Hf, 2.9-4.3
wt % of Cr, 0-9.9 wt % of Co, 4.1-14.0 wt % of Ru, 4.0 wt % or less
of Nb, 2.0 wt % or less of Ti, 0.05 wt % or less of B, 0.15 wt % or
less of C, 0.1 wt % or less of Si, 0.1 wt % or less of Y, 0.1 wt %
or less of La, 0.1 wt % or less of Ce, 1 wt % or less of V and 0.1
wt % or less of Zr.
[0026] Furthermore, the above described Ni-based single crystal
super alloy is more preferably having a composition comprising
5.0-7.0 wt % of Al, 4.0-10.0 wt % of Ta, 1.1-4.5 wt % of Mo,
4.0-10.0 wt % of W, 3.1-8.0 wt % of Re, 0-0.50 wt % of Hf, 2.9-5.0
wt % of Cr, 0-9.9 wt % of Co, 6.5-14.0 wt % of Ru, 4.0 wt % or less
of Nb, 2.0 wt % or less of Ti, 0.05 wt % or less of B, 0.15 wt % or
less of C, 0.1 wt % or less of Si, 0.1 wt % or less of Y, 0.1 wt %
or less of La, 0.1 wt % or less of Ce, 1 wt % or less of V and 0.1
wt % or less of Zr.
[0027] Furthermore, the above described Ni-based single crystal
super alloy is more preferably having a composition comprising
5.0-7.0 wt % of Al, 4.0-6.0 wt % of Ta, 3.3-4.5 wt % of Mo,
4.0-10.0 wt % of W, 3.1-8.0 wt % of Re, 0-0.50 wt % of Hf, 2.0-5.0
wt % of Cr, 0-9.9 wt % of Co, 4.1-14.0 wt % of Ru, 4.0 wt % or less
of Nb, 2.0 wt % or less of Ti, 0.05 wt % or less of B, 0.15 wt % or
less of C, 0.1 wt % or less of Si, 0.1 wt % or less of Y, 0.1 wt %
or less of La, 0.1 wt % or less of Ce, 1 wt % or less of V and 0.1
wt % or less of Zr.
[0028] Furthermore, the above described Ni-based single crystal
super alloy is more preferably having a composition comprising
5.0-7.0 wt % of Al, 4.0-5.6 wt % of Ta, 3.3-4.5 wt % of Mo,
4.0-10.0 wt % of W, 3.1-8.0 wt % of Re, 0-0.50 wt % of Hf, 2.0-5.0
wt % of Cr, 0-9.9 wt % of Co, 4.1-14.0 wt % of Ru, 4.0 wt % or less
of Nb, 2.0 wt % or less of Ti, 0.05 wt % or less of B, 0.15 wt % or
less of C, 0.1 wt % or less of Si, 0.1 wt % or less of Y, 0.1 wt %
or less of La, 0.1 wt % or less of Ce, 1 wt % or less of V and 0.1
wt % or less of Zr.
[0029] Furthermore, the above described Ni-based single crystal
super alloy is more preferably having a composition comprising
5.0-7.0 wt % of Al, 4.0-10.0 wt % of Ta, 3.1-4.5 wt % of Mo,
4.0-10.0 wt % of W, 3.1-8.0 wt % of Re, 0-0.50 wt % of Hf, 2.0-5.0
wt % of Cr, 0-9.9 wt % of Co, 4.1-14.0 wt % of Ru, 4.0 wt % or less
of Nb, 0.05 wt % or less of B, 0.15 wt % or less of C, 0.1 wt % or
less of Si, 0.1 wt % or less of Y, 0.1 wt % or less of La, 0.1 wt %
or less of Ce, 1 wt % or less of V and 0.1 wt % or less of Zr.
[0030] Furthermore, the above described Ni-based single crystal
super alloy is more preferably having a composition comprising
5.8-7.0 wt % of Al, 4.0-10.0 wt % of Ta, 3.1-4.5 wt % of Mo,
4.0-10.0 wt % of W, 3.1-8.0 wt % of Re, 0-0.50 wt % of Hf, 2.0-5.0
wt % of Cr, 0-9.9 wt % of Co, 4.1-14.0 wt % of Ru, 4.0 wt % or less
of Nb, 2.0 wt % or less of Ti, 0.05 wt % or less of B, 0.15 wt % or
less of C, 0.1 wt % or less of Si, 0.1 wt % or less of Y, 0.1 wt %
or less of La, 0.1 wt % or less of Ce, 1 wt % or less of V and 0.1
wt % or less of Zr.
[0031] Furthermore, the above described Ni-based single crystal
super alloy is more preferably having a composition comprising
5.0-7.0 wt % of Al, 4.0-10.0 wt % of Ta, 3.1-4.5 wt % of Mo,
4.0-10.0 wt % of W, 3.1-8.0 wt % of Re, 0-0.50 wt % of Hf, 2.9-4.3
wt % of Cr, 0-9.9 wt % of Co, 4.1-14.0 wt % of Ru, 4.0 wt % or less
of Nb, 2.0 wt % or less of Ti, 0.05 wt % or less of B, 0.15 wt % or
less of C, 0.1 wt % or less of Si, 0.1 wt % or less of Y, 0.1 wt %
or less of La, 0.1 wt % or less of Ce, 1 wt % or less of V and 0.1
wt % or less of Zr.
[0032] In addition, the above described Ni-based single crystal
super alloy is more preferably having a composition comprising
5.0-7.0 wt % of Al, 4.0-10.0 wt % of Ta+Nb+Ti, 3.3-4.5 wt % of Mo,
4.0-10.0 wt % of W, 3.1-8.0 wt % of Re, 0-0.50 wt % of Hf, 2.0-5.0
wt % of Cr, 0-9.9 wt % of Co, 4.1-14.0 wt % of Ru, 0.05 wt % or
less of B, 0.15 wt % or less of C, 0.1 wt % or less of Si, 0.1 wt %
or less of Y, 0.1 wt % or less of La, 0.1 wt % or less of Ce, 1 wt
% or less of V and 0.1 wt % or less of Zr.
[0033] Moreover, the Ni-based single crystal super alloy of the
present invention is characterized by a2.ltoreq.0.999a1 when the
lattice constant of the matrix is taken to be a1 and the lattice
constant of the precipitation phase is taken to be a2 in the
Ni-based single crystal super alloys previously described.
[0034] According to this Ni-based single crystal super alloy, the
relationship between a1 and a2 is such that a2.ltoreq.0.999a1 when
the lattice constant of the matrix is taken to be a1 and the
lattice constant of the precipitation phase is taken to be a2, and
since the lattice constant a2 of the precipitation phase is -0.1%
or less of the lattice constant a1 of the matrix, the precipitation
phase that precipitates in the matrix precipitates so as to extend
continuously in the direction perpendicular to the direction of the
load. As a result, strength at high temperatures can be enhanced
without dislocation defects moving within the alloy structure under
stress.
[0035] In this case, it is more preferable that the lattice
constant of the crystals of the precipitation phase a2 is 0.9965 or
less of the lattice constant of the crystals of the matrix a1
[0036] Furthermore, the Ni-based single crystal super alloy of the
present invention is characterized by comprising the feature that
the dislocation space of the alloy is 40 nm or less.
BRIEF DESCRIPTION OF DRAWINGS
[0037] FIG. 1 is a diagram showing a relationship between change of
lattice misfit of the alloy and creep rupture life of the
alloy.
[0038] FIG. 2 is a diagram showing a relationship between
dislocation space of the alloy and creep rupture life of the
alloy.
[0039] FIG. 3 is a transmission electron microgram of the Ni-based
single crystal super alloy showing an embodiment of the dislocation
networks and dislocation space of the Ni-based single crystal super
alloy of the present invention.
BEST MODE FOR CARRYING OUT THE INVENTION
[0040] The following provides a detailed explanation for carrying
out the present invention.
[0041] The Ni-based single crystal super alloy of the present
invention is an alloy comprised of Al, Ta, Mo, W, Re, Hf, Cr, Co,
Ru, Ni (remainder) and unavoidable impurities.
[0042] The above Ni-based single crystal super alloy is an alloy
having a composition comprising 5.0-7.0 wt % of Al, 4.0-10.0 wt %
of Ta, 1.1-4.5 wt % of Mo, 4.0-10.0 wt % of W, 3.1-8.0 wt % of Re,
0-0.50 wt % of Hf, 2.0-5.0 wt % of Cr, 0-9.9 wt % of Co and
4.1-14.0 wt % of Ru, with the remainder consisting of Ni and
unavoidable impurities.
[0043] In addition, the above Ni-based single crystal super alloy
is an alloy having a composition comprising 5.0-7.0 wt % of Al,
4.0-6.0 wt % of Ta, 1.1-4.5 wt % of Mo, 4.0-10.0 wt % of W, 3.1-8.0
wt % of Re, 0-0.50 wt % of Hf, 2.0-5.0 wt % of Cr, 0-9.9 wt % of Co
and 4.1-14.0 wt % of Ru, with the remainder consisting of Ni and
unavoidable impurities.
[0044] Moreover, the above Ni-based single crystal super alloy is
an alloy having a composition comprising 5.0-7.0 wt % of Al,
4.0-6.0 wt % of Ta, 2.9-4.5 wt % of Mo, 4.0-10.0 wt % of W, 3.1-8.0
wt % of Re, 0-0.50 wt % of Hf, 2.0-5.0 wt % of Cr, 0-9.9 wt % of Co
and 4.1-14.0 wt % of Ru, with the remainder consisting of Ni and
unavoidable impurities.
[0045] All of the above alloys have an austenite phase in the form
of a .gamma. phase (matrix) and an intermediate regular phase in
the form of a .gamma.' phase (precipitation phase) that is
dispersed and precipitated in the matrix. The .gamma.' phase is
mainly composed of an intermetallic compound represented by
Ni.sub.3Al, and the strength of the Ni-based single crystal super
alloy at high temperatures is improved by this .gamma.' phase.
[0046] Cr is an element that has superior oxidation resistance and
improves the high-temperature corrosion resistance of the Ni-based
single crystal super alloy. The composite ratio of Cr is preferably
within the range of 2.0 wt % or more to 5.0 wt % or less, and more
preferably 2.9 wt %. This ratio is more preferably within the range
of 2.9 wt % or more to 5.0 wt % or less, more preferably within the
range of 2.9 wt % or more to 4.3 wt % or less, and most preferably
2.9 wt %. If the composite ratio of Cr is less than 2.0 wt %, the
desired high-temperature corrosion resistance cannot be secured,
thereby making this undesirable. If the composite ratio of Cr
exceeds 5.0 wt %, in addition to precipitation of the .gamma.'
phase being inhibited, harmful phases such as a .sigma. phase or
.mu. phase form that cause a decrease in strength at high
temperatures, thereby making this undesirable.
[0047] In addition to improving strength at high temperatures by
dissolving into the matrix in the form of the .gamma. phase in the
presence of W and Ta, Mo also improves strength at high
temperatures due to precipitation hardening. Furthermore, Mo also
improves the aftermentioned lattice misfit and dislocation networks
of the alloy which relate characteristics of this alloy.
[0048] The composite ratio of Mo is preferably within the range of
1.1 wt % or more to 4.5 wt % or less, more preferably within the
range of 2.9 wt % or more to 4.5 wt % or less. This ratio is more
preferably within the range of 3.1 wt % or more to 4.5 wt % or
less, more preferably within the range of 3.3 wt % or more to 4.5
wt % or less, and most preferably 3.1 wt % or 3.9 wt %. If the
composite ratio of Mo is less than 1.1 wt %, strength at high
temperatures cannot be maintained at the desired level, thereby
making this undesirable. If the composite ratio of Mo exceeds 4.5
wt %, strength at high temperatures decreases, and corrosion
resistance at high temperatures also decreases, thereby making this
undesirable.
[0049] W improves strength at high temperatures due to the actions
of solution hardening and precipitation hardening in the presence
of Mo and Ta as previously mentioned. The composite ratio of W is
preferably within the range of 4.0 wt % or more to 10.0 wt % or
less, and most preferably 5.9 wt % or 5.8 wt %. If the composite
ratio of W is less than 4.0 wt %, strength at high temperatures
cannot be maintained at the desired level, thereby making this
undesirable. If the composite ratio of W exceeds 10.0 wt %,
high-temperature corrosion resistance decreases, thereby making
this undesirable.
[0050] Ta improves strength at high temperatures due to the actions
of solution hardening and precipitation hardening in the presence
of Mo and W as previously mentioned, and also improves strength at
high temperatures as a result of a portion of the Ta undergoing
precipitation hardening relative to the .gamma.' phase. The
composite ratio of Ta is preferably within the range of 4.0 wt % or
more to 10.0 wt % or less, more preferably within the range of 4.0
wt % or more to 6.0 wt % or less. This ratio is more preferably
within the range of 4.0 wt % or more to 5.6 wt % or less, and most
preferably 5.6 wt % or 5.82 wt %. If the composite ratio of Ta is
less than 4.0 wt %, strength at high temperatures cannot be
maintained at the desired level, thereby making this undesirable.
If the composite ratio of Ta exceeds 10.0 wt %, the .sigma. phase
and .mu. phase form that cause a decrease in strength at high
temperatures, thereby making this undesirable.
[0051] Al improves strength at high temperatures by compounding
with Ni to form an intermetallic compound represented by
Ni.sub.3Al, which composes the .gamma.' phase that finely and
uniformly disperses and precipitates in the matrix, at a ratio of
60-70% in terms of volume percent. The composite ratio of Al is
preferably within the range of 5.0 wt % or more to 7.0 wt % or
less. This ratio is more preferably within the range of 5.8 wt % or
more to 7.0 wt % or less, and most preferably 5.9 wt % or 5.8 wt %.
If the composite ratio of Al is less than 5.0 wt %, the
precipitated amount of the .gamma.' phase becomes insufficient, and
strength at high temperatures cannot be maintained at the desired
level, thereby making this undesirable. If the composite ratio of
Al exceeds 7.0 wt %, a large amount of a coarse .gamma. phase
referred to as the eutectic .gamma.' phase is formed, and this
eutectic .gamma.' phase prevents solution treatment and makes it
impossible to maintain strength at high temperatures at a high
level, thereby making this undesirable.
[0052] Hf is an element that segregates at the grain boundary and
improves strength at high temperatures by strengthening the grain
boundary as a result of being segregated at the grain boundary
between the .gamma. phase and the .gamma.' phase. The composite
ratio of Hf is preferably within the range of 0.01 wt % or more to
0.50 wt % or less, and most preferably 0.10 wt %. If the composite
ratio of Hf is less than 0.01 wt %, the precipitated amount of the
.gamma.' phase becomes insufficient and strength at high
temperatures cannot be maintained at the desired level, thereby
making this undesirable. However, the composite ratio of Hf may be
within the range of 0 wt % or more to less than 0.01 wt %, if
necessary. Furthermore, if the composite ratio of Hf exceeds 0.50
wt %, local melting is induced which results in the risk of
decreased strength at high temperatures, thereby making this
undesirable.
[0053] Co improves strength at high temperatures by increasing the
solution limit at high temperatures relative to the matrix such as
Al and Ta, and dispersing and precipitating a fine .gamma.' phase
by heat treatment. The composite ratio of Co is preferably within
the range of 0.1 wt % or more to 9.9 wt % or less, and most
preferably 5.8 wt %. If the composite ratio of Co is less than 0.1
wt %, the precipitated amount of the .gamma.' phase becomes
insufficient and the strength at high temperatures cannot be
maintained, thereby making this undesirable. However, the composite
ratio of Co may be within the range of 0 wt % or more to less than
0.1 wt %, if necessary. Furthermore, if the composite ratio of Co
exceeds 9.9 wt %, the balance with other elements such as Al, Ta,
Mo, W, Hf and Cr is disturbed resulting in the precipitation of
harmful phases that cause a decrease in strength at high
temperatures, thereby making this undesirable.
[0054] Re improves strength at high temperatures due to solution
strengthening as a result of dissolving in the matrix in the form
of the .gamma. phase. On the other hand, if a large amount of Re is
added, the harmful TCP phase precipitates at high temperatures,
resulting in the risk of decreased strength at high temperatures.
Thus, the composite ratio of Re is preferably within the range of
3.1 wt % or more to 8.0 wt % or less, and most preferably 4.9 wt %.
If the composite ratio of Re is less than 3.1 wt %, solution
strengthening of the .gamma. phase becomes insufficient and
strength at high temperatures cannot be maintained at the desired
level, thereby making this undesirable. If the composite ratio of
Re exceeds 8.0 wt %, the TCP phase precipitates at high
temperatures and strength at high temperatures cannot be maintained
at a high level, thereby making this undesirable.
[0055] Ru improves strength at high temperatures by inhibiting
precipitation of the TCP phase. The composite ratio of Ru is
preferably within the range of 4.1 wt % or more to 14.0 wt % or
less. This ratio is more preferably within the range of 10.0 wt %
or more to 14.0 wt % or less, or preferably within the range of 6.5
wt % or more to 14.0 wt % or less, and most preferably 5.0 wt %,
6.0 wt % or 7.0 wt %. If the composite ratio of Ru is less than 1.0
wt %, the TCP phase precipitates at high temperatures and strength
at high temperatures cannot be maintained at a high level, thereby
making this undesirable. If the composite ratio of Ru is less than
4.1 wt %, strength at high temperatures decreases compared to the
case when the composite ratio of Ru is 4.1 wt % or more.
Furthermore, if the composite ratio of Ru exceeds 14.0 wt %, the
.epsilon. phase precipitates and strength at high temperatures
decreases which is also undesirable.
[0056] Particularly in the present invention, by adjusting the
composite ratios of Al, Ta, Mo, W, Hf, Cr, Co and Ni to the optimum
ratios, together with improving strength at high temperatures by
setting the aftermentioned lattice misfit and dislocation networks
of the alloy which are calculated from the lattice constant of the
.gamma. phase and the lattice constant of the .gamma.' phase within
their optimum ranges, and precipitation of the TCP phase can be
inhibited by adding Ru. Furthermore, by adjusting the composite
ratios of Al, Cr, Ta and Mo to the aforementioned ratios, the
production cost for the alloy can be decreased. In addition,
relative strength of the alloy can be increased and the lattice
misfit and dislocation networks of the alloy can be adjusted to the
optimum value.
[0057] In addition, in usage environments at high temperatures from
1273 K (1000.degree. C.) to 1373K (1100.degree. C.), when the
lattice constant of the crystals that compose the matrix in the
form of the .gamma. phase is taken to be a1, and the lattice
constant of the crystals that compose the precipitation phase in
the form of the .gamma.' phase is taken to be a2, then the
relationship between a1 and a2 is preferably such that
a2.ltoreq.0.999a1. Namely, lattice constant a2 of the crystals of
the precipitation phase is preferably -0.1% or less lattice
constant a1 of the crystals of the matrix. Furthermore, it is more
preferable that the lattice constant of the crystals of the
precipitation phase a2 is 0.9965 or less of the lattice constant of
the crystals of the matrix a1. In this case, the above-described
relationship between a1 and a2 becomes a2.ltoreq.0.9965a1. In the
following descriptions, the percentage of the lattice constant a2
relative to the lattice constant a1 is called "lattice misfit".
[0058] In addition, in the case both of the lattice constants are
in the above relationship, since the precipitation phase
precipitates so as to extend continuously in the direction
perpendicular to the direction of the load when the precipitation
phase precipitates in the matrix due to heat treatment, creep
strength can be enhanced without movement of dislocation defects in
the alloy structure in the presence of stress.
[0059] In order to make the relationship between lattice constant
a1 and lattice constant a2 such that a2.ltoreq.0.999a1, the
composition of the composite elements that compose the Ni-based
single crystal super alloy is suitably adjusted.
[0060] FIG. 1 shows a relationship between the lattice misfit of
the alloy and the time until the alloy demonstrates creep rupture
(creep rupture life).
[0061] In FIG. 1, when the lattice misfit is approximately -0.35 or
lower, the creep rupture life is approximately higher than the
required value (the value shown by a dotted line in a vertical axis
of the figure). Therefore, in the present invention, the preferable
value of the lattice misfit is determined to -0.35 or lower. In
order to maintain the lattice misfit to -0.35 or lower, the
composition of Mo is maintained to a high level, and the
composition of the other composite elements is suitably
adjusted.
[0062] According to the above Ni-based super crystal super alloy,
precipitation of the TCP phase, which causes decreased creep
strength, during use at high temperatures is inhibited by addition
of Ru. In addition, by setting the composite ratios of other
composite elements to their optimum ranges, the lattice constant of
the matrix (.gamma. phase) and the lattice constant of the
precipitation phase (.gamma.' phase) can be made to have optimum
values. As a result, creep strength at high temperatures can be
improved.
[0063] Ti can be further included in the above Ni-based super
crystal super alloy. The composite ratio of Ta is preferably within
the range of 0 wt % or more to 2.0 wt % or less. If the composite
ratio of Ti exceeds 2.0 wt %, the harmful phase precipitates and
the strength at high temperatures cannot be maintained, thereby
making this undesirable.
[0064] Furthermore, Nb can be further included in the above
Ni-based super crystal super alloy. The composite ratio of Nb is
preferably within the range of 0 wt % or more to 4.0 wt % or less.
If the composite ratio of Nb exceeds 4.0 wt %, the harmful phase
precipitates and the strength at high temperatures cannot be
maintained, thereby making this undesirable.
[0065] Alternatively, strength at high temperatures can be improved
by adjusting the total composite ratio of Ta, Nb and Ti (Ta+Nb+Ti)
within the range of 4.0 wt % or more to 10.0 wt % or less.
[0066] Furthermore, in addition to the unavoidable impurities, B,
C, Si, Y, La, Ce, V and Zr and the like can be included in the
above Ni-based super crystal super alloy, for example. When the
alloy includes at least one of elements selected from B, C, Si, Y,
La, Ce, V and Zr, the composite ratio of each element is preferably
0.05 wt % or less of B, 0.15 wt % or less of C, 0.1 wt % or less of
Si, 0.1 wt % or less of Y, 0.1 wt % or less of La, 0.1 wt % or less
of Ce, 1 wt % or less of V and 0.1 wt % or less of Zr. If the
composite ratio of each element exceeds the above range, the
harmful phase precipitates and the strength at high temperatures
cannot be maintained, thereby making this undesirable.
[0067] furthermore, in the above Ni-based single crystal super
alloy, it is preferable that a dislocation space of the alloy is 40
nm or less. The reticulated dislocation (displacement of atoms
which are connected as a line) in the alloy is called dislocation
networks, and a space between adjacent reticulations is called
"dislocation space". FIG. 2 shows a relationship between the
dislocation space of the alloy and the time until the alloy
demonstrates creep rupture (creep rupture life).
[0068] In FIG. 2, when the dislocation space is approximately 40 nm
or lower, the creep rupture life is approximately higher than the
required value (the value shown by a dotted line in a vertical axis
of the figure). Therefore, in the present invention, the preferable
value of the dislocation space is determined to 40 nm or lower. In
order to maintain the dislocation space to 40 nm or lower, the
composition of Mo is maintained to a high level, and the
composition of the other composite elements is suitably
adjusted.
[0069] FIG. 3 is a transmission electron microgram of the Ni-based
single crystal super alloy showing an embodiment (aftermentioned
embodiment 3) of the dislocation networks and dislocation space of
the Ni-based single crystal super alloy of the present invention.
As shown in FIG. 3, in case of the Ni-based single crystal super
alloy of the present invention, the dislocation space is 40 nm or
lower.
[0070] In addition, some of the conventional Ni-based single
crystal super alloys may cause reverse partitioning, however, in
Ni-based single crystal super alloy of the present invention does
not cause reverse partitioning.
EMBODIMENTS
[0071] The effect of the present invention is shown using following
embodiments.
[0072] Melts of various Ni-based single crystal super alloys were
prepared using a vacuum melting furnace, and alloy ingots were cast
using the alloy melts. The composite ratio of each of the alloy
ingots (reference examples 1-6, embodiments 1-14) is shown in Table
2. TABLE-US-00002 TABLE 2 Sample (alloy Elements (wt %) name) Al Ta
Nb Mo W Re Hf Cr Co Ru Ni Reference 6.0 5.8 3.2 6.0 5.0 0.1 3.0 6.0
2.0 Rem Example 1 Reference 5.9 5.7 3.2 5.9 5.0 0.1 3.0 5.9 3.0 Rem
Example 2 Reference 6.0 6.0 4.0 6.0 5.0 0.1 3.0 6.0 3.0 Rem Example
3 Reference 5.9 5.9 4.0 5.9 5.0 0.1 3.0 5.9 4.0 Rem Example 4
Reference 5.9 5.7 3.1 5.9 4.9 0.1 2.9 5.9 4.0 Rem Example 5
Reference 5.7 5.7 2.9 7.7 4.8 0.1 2.9 5.7 3.0 Rem Example 6 Embodi-
5.9 5.9 3.9 5.9 4.9 0.1 2.9 5.9 5.0 Rem ment 1 Embodi- 5.8 5.6 3.1
5.8 4.9 0.1 2.9 5.8 5.0 Rem ment 2 Embodi- 5.8 5.8 3.9 5.8 4.9 0.1
2.9 5.8 6.0 Rem ment 3 Embodi- 5.6 5.6 2.8 5.6 6.9 0.1 2.9 5.6 5.0
Rem ment 4 Embodi- 5.6 5.0 0.5 2.8 5.6 6.9 0.1 2.9 5.6 5.0 Rem ment
5 Embodi- 5.6 5.6 1.0 2.8 5.6 4.7 0.1 2.9 5.6 5.0 Rem ment 6
Embodi- 5.8 5.6 3.9 5.8 4.9 0.1 2.9 5.8 6.0 Rem ment 7 Embodi- 5.7
5.5 1.0 3.8 5.7 4.8 0.1 2.8 5.5 5.9 Rem ment 8 Embodi- 5.8 5.6 3.1
6.0 5.0 0.1 2.9 5.8 4.6 Rem ment 9 Embodi- 5.8 5.6 3.1 6.0 5.0 0.1
2.9 5.8 5.2 Rem ment 10 Embodi- 5.8 5.6 3.3 6.0 5.0 0.1 2.9 5.8 5.2
Rem ment 11 Embodi- 5.8 5.6 3.3 6.0 5.0 0.1 2.9 5.8 6.0 Rem ment 12
Embodi- 5.9 2.9 1.5 3.9 5.9 4.9 0.1 2.9 5.9 6.1 Rem ment 13 Embodi-
5.7 5.52 3.1 5.7 4.8 0.1 2.9 5.7 7.0 Rem ment 14
[0073] Next, solution treatment and aging treatment were performed
on the alloy ingots followed by observation of the state of the
alloy structure with a scanning electron microscope (SEM). Solution
treatment consisted of holding for 1 hour at 1573K (1300.degree.
C.) followed by heating to 1613K (1340.degree. C.) and holding for
5 hours. In addition, aging treatment consisted of consecutively
performing primary aging treatment consisting of holding for 4
hours at 1273K-1423K (1000.degree. C.-1150.degree. C.) and
secondary aging treatment consisting of holding for 20 hours at
1143K (870.degree. C.).
[0074] As a result, a TCP phase was unable to be confirmed in the
structure of each sample.
[0075] Next, a creep test was performed on each sample that
underwent solution treatment and aging treatment. The creep test
consisted of measuring the time until each sample (reference
examples 1-6 and embodiments 1-14) demonstrated creep rupture as
the sample life under each of the temperature and stress conditions
shown in Table 3. Furthermore, the value of the lattice misfit of
each sample was also measured, and the result thereof is disclosed
in Table 3. In addition, the value of the lattice misfit of each of
the conventional alloys shown in Table 1 (comparative examples 1-5)
was also measured, and the result thereof is disclosed in Table 4.
TABLE-US-00003 TABLE 3 Creep test conditions/ rupture life (h) 1273
K 1373 K Sample (1000.degree. C.) (1100.degree. C.) Lattice (alloy
name) 245 MPa 137 MPa Misfit Reference Example 1 209.35 105.67
-0.39 Reference Example 2 283.20 158.75 -0.40 Reference Example 3
219.37 135.85 -0.56 Reference Example 4 274.38 153.15 -0.58
Reference Example 5 328.00 487.75 -0.58 Reference Example 6 203.15
-0.41 Embodiment 1 5.09.95 32.6.50 -0.60 Embodiment 2 420.60 753.95
-0.42 Embodiment 3 1062.50 -0.62 Embodiment 4 966.00 -0.44
Embodiment 5 1256.00 -0.48 Embodiment 6 400.00 -0.45 Embodiment 7
1254.00 -0.60 Embodiment 8 682.00 -0.63 Embodiment 9 550.00 -0.42
Embodiment 10 658.50 -0.45 Embodiment 11 622.00 -0.48 Embodiment 12
683.50 -0.51 Embodiment 13 412.7 766.35 -0.62 Embodiment 14 1524.00
-0.45
[0076] TABLE-US-00004 TABLE 4 Sample (alloy name) Lattice Misfit
Comparative Example 1 (CMSX-2) -0.36 Comparative Example 2 (CMSX-4)
-0.14 Comparative Example 3 (ReneN6) -0.22 Comparative Example 4
(CMSX-10K) -0.14 Comparative Example 5 (3B) -0.25
[0077] As is clear from Table 3, the samples of the reference
examples 1-6 and embodiments 1-14 were determined to have high
strength even under high temperature conditions of 1273K
(1000.degree. C.). In particular, reference example 5 having a
composition of 4.0 wt % of Ru, embodiments 1, 2, 4, 9, 10 and 11
having a composition approximately 5.0 wt % of Ru, embodiments 3,
12 and 13 having a composition of 6.0 wt % of Ru, and embodiment 14
having a composition of 7.0 wt % of Ru, were determined to have
high strength at high temperature.
[0078] Furthermore, as is clear from Tables 3 and 4, the lattice
misfit of comparative examples were -0.35 and more, whereas those
of reference examples 1-6 and embodiments 1-14 were -0.35 or
less.
[0079] In addition, the creep rupture characteristics (withstand
temperature) were compared for the alloys of the prior art shown in
Table 1 (Comparative Examples 1 through 5) and the sample shown in
Table 2 (reference examples 1-6 and embodiments 1-14). The result
thereof is disclosed in Table 5. Creep rupture characteristics were
determined either as a result of measuring the temperature until
the sample ruptured under conditions of applying stress of 137 MPa
for 1000 hours, or converting the rupture temperature of the sample
under those conditions. TABLE-US-00005 TABLE 5 Sample (alloy name)
Withstand temperature (.degree. C.) Reference Example 1 1315 K
(1042.degree. C.) Reference Example 2 1325 K (1052.degree. C.)
Reference Example 3 1321 K (1048.degree. C.) Reference Example 4
1324 K (1051.degree. C.) Reference Example 5 1354 K (1081.degree.
C.) Reference Example 6 1332 K (1059.degree. C.) Embodiment 1 1344
K (1071.degree. C.) Embodiment 2 1366 K (1093.degree. C.)
Embodiment 3 1375 K (1102.degree. C.) Embodiment 4 1372 K
(1099.degree. C.) Embodiment 5 1379 K (1106.degree. C.) Embodiment
6 1379 K (1106.degree. C.) Embodiment 7 1379 K (1106.degree. C.)
Embodiment 8 1363 K (1090.degree. C.) Embodiment 9 1358 K
(1085.degree. C.) Embodiment 10 1362 K (1089.degree. C.) Embodiment
11 1361 K (1088.degree. C.) Embodiment 12 1363 K (1090.degree. C.)
Embodiment 13 1366 K (1093.degree. C.) Embodiment 14 1384 K
(1111.degree. C.) Comparative Example 1 (CMSX-2) 1289 K
(1016.degree. C.) Comparative Example 2 (CMSX-4) 1306 K
(1033.degree. C.) Comparative Example 3 (ReneN6) 1320 K
(1047.degree. C.) Comparative Example 4 (CMSX-10K) 1345 K
(1072.degree. C.) Comparative Example 5 (3B) 1353 K (1080.degree.
C.) (Converted to 137 MPa, 1000 hours)
[0080] As is clear from Table 5, the samples of reference examples
1-6 and embodiments 1-14 were determined to have a high withstand
temperature (1356K (1083.degree. C.)) equal to or greater than the
alloys of the prior art (comparative Examples 1-5). In particular,
samples of reference examples 1-6 and embodiments 1-14 were
determined to have a high withstand temperature (embodiment 1:
1344K (1071.degree. C.), embodiment 2: 1366K (1093.degree. C.),
embodiment 3: 1375K (1102.degree. C.), embodiment 4: 1372K
(1099.degree. C.), embodiment 5: 1379K (1106.degree. C.),
embodiment 6: 1379K (1106.degree. C.), embodiment 7: 1379K
(1106.degree. C.), embodiment 8: 1363K (1090.degree. C.),
embodiment 9: 1358K (1085.degree. C.), embodiment 10: 1362K
(1089.degree. C.), embodiment 11: 1361K (1088.degree. C.),
embodiment 12: 1363K (1090.degree. C.), embodiment 13: 1366K
(1093.degree. C.) and embodiment 14: 1384K (1111.degree. C.).
[0081] Thus, this alloy has a higher heat resistance temperature
than Ni-based single crystal super alloys of the prior art, and was
determined to have high strength even at high temperatures.
[0082] Furthermore, in the Ni-based single crystal super alloy, if
the composite ratio of Ru excessively increases, the .epsilon.
phase precipitates and strength at high temperatures deceases.
Therefore, the composite ratio of Ru is preferably be determined to
a range so as to keep the balance against the composition of the
other composite elements is suitably adjusted (4.1 wt % or more to
14.0 wt % or less, for example).
* * * * *