U.S. patent application number 10/741979 was filed with the patent office on 2005-03-03 for high temperature powder metallurgy superalloy with enhanced fatigue & creep resistance.
Invention is credited to Hieber, Andrew F., Merrick, Howard F..
Application Number | 20050047954 10/741979 |
Document ID | / |
Family ID | 34973221 |
Filed Date | 2005-03-03 |
United States Patent
Application |
20050047954 |
Kind Code |
A1 |
Hieber, Andrew F. ; et
al. |
March 3, 2005 |
HIGH TEMPERATURE POWDER METALLURGY SUPERALLOY WITH ENHANCED FATIGUE
& CREEP RESISTANCE
Abstract
A nickel based superalloy composition comprising about 16.5 to
about 20.5 weight % Co, about 9.5 to about 12.5 weight % Cr, about
1.8 to about 3.2 weight % Mo, about 4.25 to about 6.0 weight % W,
about 3.0 to about 4.2 weight % Al, about 3.0 to about 4.4 weight %
Ti, about 1.0 to about 2.0 weight % Ta, about 0.6 to about 1.8
weight % Nb, about 0.01 to about 0.08 weight % C, about 0.01 to
about 0.06 weight % B, and about 0.04 to about 0.15 weight % Zr,
balance Ni.
Inventors: |
Hieber, Andrew F.;
(Scottsdale, AZ) ; Merrick, Howard F.; (Phoenix,
AZ) |
Correspondence
Address: |
HONEYWELL INTERNATIONAL INC.
101 COLUMBIA ROAD
P O BOX 2245
MORRISTOWN
NJ
07962-2245
US
|
Family ID: |
34973221 |
Appl. No.: |
10/741979 |
Filed: |
December 19, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10741979 |
Dec 19, 2003 |
|
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|
10651480 |
Aug 29, 2003 |
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Current U.S.
Class: |
420/448 ;
148/428 |
Current CPC
Class: |
B22F 2998/00 20130101;
C22F 1/10 20130101; B22F 2998/00 20130101; B22F 5/04 20130101; B22F
3/15 20130101; C22C 1/0433 20130101; C22C 19/056 20130101 |
Class at
Publication: |
420/448 ;
148/428 |
International
Class: |
C22C 019/05 |
Claims
1-12. (canceled).
13. The nickel based superalloy composition of claim 24,
comprising: 18.2 weight % Co, 11.2 weight % Cr, 2.65 weight % Mo,
4.8 weight % W, 3.57 weight % Al, 3.86 weight % Ti, 1.65 weight %
Ta, 0.95 weight % Nb, 0.027 weight % C, 0.028 weight % B, and 0.07
weight % Zr.
14. The nickel based superalloy composition of claim 13, wherein
said superalloy exhibits a LCF life, at 800.degree. F., R=-1, 0.65%
strain, of greater than about 260,000 cycles.
15. The nickel based superalloy composition of claim 24,
comprising: 17.8 weight % Co, 11.0 weight % Cr, 2.6 weight % Mo,
5.0 weight % W, 3.58 weight % Al, 3.9 weight % Ti, 1.47 weight %
Ta, 1.03 weight % Nb, 0.028 weight % C, 0.028 weight % B, and 0.10
weight % Zr.
16. The nickel based superalloy composition of claim 15, wherein
said superalloy exhibits a LCF life, at 800.degree. F., R=-1, 0.65%
strain, of greater than about 260,000 cycles.
17. The nickel based superalloy composition of claim 24,
comprising: 16.9 weight % Co, 11.1 weight % Cr, 2.55 weight % Mo,
5.5 weight % W, 3.79 weight % Al, 3.97 weight % Ti, 1.57 weight %
Ta, 0.91 weight % Nb, 0.033 weight % C, 0.035 weight % B, and 0.09
weight % Zr.
18. The nickel based superalloy composition of claim 17, wherein
said superalloy exhibits a LCF life, at 1100.degree. F., R=0, 0.7%
strain, of greater than about 470,000 cycles.
19. The nickel based superalloy composition of claim 24,
comprising: 17.4 weight % Co, 11.0 weight % Cr, 2.56 weight % Mo,
5.5 weight % W, 3.64 weight % Al, 3.8 weight % Ti, 1.47 weight %
Ta, 0.94 weight % Nb, 0.03 weight % C, 0.03 weight % B, and 0.1
weight % Zr.
20. The nickel based superalloy composition of claim 19, wherein
said superalloy exhibits a LCF life, at 1100.degree. F., R=0, 0.7%
stain, of greater Man about 200,000 cycles.
21. The nickel based superalloy composition of claim 19, wherein
said superalloy exhibits a 0.2% creep time, at 1300.degree. F. and
100 ksi, of greater than about 400 hours.
22. A gas turbine engine component formed from the nickel based
superalloy composition of claim 124.
23. The gas turbine engine component of claim 22, wherein said gas
turbine engine component is selected from the group consisting of a
compressor disk, a turbine disk, a seal plate, and a spacer.
24. A nickel based superalloy composition, comprising: 16.5 to 20.5
weight % Co, 9.5 to 12.5 weight % Cr, 1.8 to 3.2 weight % Mo, 4.25
to 6.0 weight % W, 3.0 to 4.2 weight % Al, 3.0 to 4.4 weight % Ti,
1.0 to 2.0 weight % Ta, 0.06 to 1.8 weight % Nb, 0.01 to 0.08
weight % C, 0.01 to 0.06 weight % B, 0.03 to 0.15 weight % Zr, and
Ni, wherein a W:Ta ratio is between 2.9 and 4.1.
25. The nickel based superalloy composition of claim 24, wherein
said W is present from 4.25 to 5.5 weight %.
26. The nickel based superalloy composition of claim 25, wherein
said W is present from 4.25 to 5.0 weight %.
27. The nickel based superalloy composition of claim 25, wherein
said W is present from 5.1 to 5.5 weight %.
28. The nickel based superalloy composition of claim 25, wherein
said Nb is present from 0.80 to 1.60 weight %.
29. A turbine disk for a gas turbine engine, said turbine disk made
from the superalloy composition of claim 24.
30. The nickel based superalloy composition of claim 24,
comprising: 16.8 to 19.8 weight % Co, 10.0 to 12.0 weight % Cr, 2.2
to 3.0 weight % Mo, 4.25 to 5.5 weight % W, 3.3 to 3.9 weight % Al,
3.3 to 4.1 weight % Ti, 1.30 to 1.80 weight % Ta, 0.80 to 1.60
weight % Nb, 0.02 to 0.05 weight % C, 0.02 to 0.05 weight % B, 0.05
to 0.12 weight % Zr, and Ni.
31. A gas turbine engine component comprising the nickel based
superalloy composition of claim 30.
32. The nickel based superalloy composition of claim 30,
comprising: 17.8 to 19.8 weight % Co, 10.0 to 12.0 weight % Cr, 2.3
to 2.9 weight % Mo, 4.25 to 5.0 weight % W, 3.3 to 3.8 weight % Al,
3.6 to 4.0 weight % Ti, 1.3 to 1.8 weight % Ta, 0.90 to 1.60 weight
% Nb, 0.02 to 0.050 weight % C, 0.020 to 0.040 weight % B, 0.05 to
0.10 weight % Zr, and Ni.
33. A gas turbine engine component comprising the nickel based
superalloy composition of claim 32.
34. The nickel based superalloy composition of claim 30,
comprising: 16.8 to 17.2 weight % Co, 10.5 to 12.0 weight % Cr, 2.4
to 2.8 weight % Mo, 5.1 to 5.5 weight % W, 3.4 to 3.8 weight % Al,
3.6 to 4.0 weight % Ti, 1.3 to 1.7 weight % Ta, 0.80 to 1.40 weight
% Nb, 0.02 to 0.05 weight % C, 0.020 to 0.040 weight % B, 0.05 to
0.10 weight % Zr, and Ni.
35. A gas turbine engine component comprising the nickel based
superalloy composition of claim 34.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part Application of
U.S. application Ser. No. 10/651,480, filed Aug. 29, 2003, the
entire contents of which are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] The present invention generally relates to a nickel based
superalloy composition. The present invention also relates to a
component comprising a nickel based superalloy composition.
[0003] Nickel based superalloys have been extensively used in
manufacturing gas turbine engine components. Gas turbine engines
having hotter exhaust gases and which operate at higher
temperatures are more efficient. To maximize the efficiency of gas
turbine engines, attempts have been made to form gas turbine engine
components, such as turbine discs, having higher operating
temperature capabilities. In particular, there is considerable
commercial interest in superalloys for turbine and compressor disk
applications which exhibit strength and creep resistance at
relatively high temperatures (e.g., 1300-1500.degree. F.), as well
as resistance to fatigue crack initiation at the lower temperatures
(e.g., 500-1100.degree. F.) often experienced in compressor and
turbine disk bores. Higher temperature dwell crack growth
resistance is also a significant parameter.
[0004] The previous generation of higher temperature capability
disk alloys of the prior art are limited to about 1200-1300.degree.
F. operating temperature, and include such commercially used alloys
as P/M Astroloy, Rene' 88 DT, and IN100. Such disk alloys,
including the most recent generation of alloys, are typically made
by inert gas atomization into powder form. The powder is
subsequently screened to an appropriate size range and consolidated
by hot compaction or by hot isostatic pressing (HIP). The
consolidated powder is then extruded into a form suitable for
isothermal forging into a shape that can be machined into an engine
component. Components may also be formed by hot isostatic pressing
(HIP) without the extrusion and isothermal forging steps, and
subsequently machined to final shape. These methods of manufacture
are common throughout the industry for high gamma prime volume
fraction disk alloys.
[0005] U.S. Pat. No. 6,521,175 B1 to Mourer, et al. discloses a
nickel based superalloy which contains 1.9 to 4.0 wt. % tungsten.
The superalloy of Mourer, et al. sacrifices some low-temperature
dwell fatigue crack growth performance to achieve improved creep
performance.
[0006] As can be seen, there is a need for a nickel based
superalloy composition which exhibits enhanced fatigue crack
initiation life at temperatures of 500 to 1200.degree. F., as well
as enhanced resistance to creep at temperatures of 1200 to
1500.degree. F. Dwell crack growth resistance at these higher
temperatures (1200 to 1500.degree. F.) is also of importance.
SUMMARY OF THE INVENTION
[0007] In one aspect of the present invention, there is provided a
nickel based superalloy composition, comprising: Ni, Co, Cr, Mo, W,
Al, Ti, Ta, Nb, C, B, and Zr, wherein W is present in an amount
greater than 4 weight %.
[0008] In another aspect of the present invention, there is
provided a nickel based superalloy composition, comprising about
16.5 to about 20.5 weight % Co, about 9.5 to about 12.5 weight %
Cr, about 1.8 to about 3.2 weight % Mo, about 4.25 to about 6.0
weight % W, about 3.0 to about 4.2 weight % Al, about 3.0 to about
4.4 weight % Ti, about 1.0 to about 2.0 weight % Ta, about 0.6 to
about 1.8 weight % Nb, about 0.01 to about 0.08 weight % C, about
0.01 to about 0.06 weight % B, and about 0.03 to about 0.15 weight
% Zr, balance Ni.
[0009] In still another aspect of the present invention, there is
provided a nickel based superalloy composition, comprising about
16.8 to about 19.8 weight % Co, about 10.0 to about 12 weight % Cr,
about 2.2 to about 3.0 weight % Mo, about 4.25 to about 5.5 weight
% W, about 3.3 to about 3.9 weight % Al, about 3.3 to about 4.1
weight % Ti, about 1.30 to about 1.80 weight % Ta, about 0.80 to
about 1.60 weight % Nb, about 0.02 to about 0.05 weight % C, about
0.02 to about 0.05 weight % B, and about 0.04 to about 0.12 weight
% Zr, balance Ni.
[0010] In a further aspect of the present invention, there is
provided a nickel based superalloy composition, comprising about
17.8 to about 19.8 weight % Co, about 10.0 to about 12.0 weight %
Cr, about 2.3 to about 2.9 weight % Mo, about 4.25 to about 5.0
weight % W, about 3.3 to about 3.8 weight % Al, about 3.5 to about
4.0 weight % Ti, about 1.3 to about 1.8 weight % Ta, about 0.90 to
about 1.6 weight % Nb, about 0.02 to about 0.05 weight % C, about
0.020 to about 0.040 weight % B, and about 0.05 to about 0.10
weight % Zr, balance Ni.
[0011] In still a further aspect of the present invention, there is
provided a nickel based superalloy composition, comprising about
16.8 to about 17.2 weight % Co, about 10.5 to about 12 weight % Cr,
about 2.4 to about 2.8 weight % Mo, about 5.1 to about 5.5 weight %
W, about 3.4 to about 3.8 weight % Al, about 3.6 to about 4.0
weight % Ti, about 1.3 to about 0.1.7 weight % Ta, about 0.80 to
about 1.40 weight % Nb, about 0.02 to about 0.05 weight % C, about
0.020 to about 0.040 weight % B, and about 0.05 to about 0.10
weight % Zr, balance Ni.
[0012] In yet another aspect of the present invention, there is
provided a nickel based superalloy composition, comprising about
16.8 to about 19.8 weight % Co, about 10.0 to about 12.0 weight %
Cr, about 2.2 to about 3.0 weight % Mo, about 4.25 to about 5.5
weight % W, about 3.3 to about 3.9 weight % Al, about 3.3 to about
4.1 weight % Ti, about 1.3 to about 1.8 weight % Ta, about 0.80 to
about 1.60 weight % Nb, about 0.02 to about 0.05 weight % C, about
0.02 to about 0.05 weight % B, and about 0.04 to about 0.12 weight
% Zr, balance Ni, wherein said superalloy has a LCF life at
1100.degree. F., R=0, 0.7% strain greater than about 200,000
cycles, and a time for 0.2% creep at 1300.degree. F. and 100 ksi
greater than about 400 hours.
[0013] These and other features, aspects and advantages of the
present invention will become better understood with reference to
the following drawings, description and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1A is a plot showing 0.2% creep and low cycle fatigue
(0.65% strain) data for alloy sample B of the invention and for a
conventional alloy (Astroloy);
[0015] FIG. 1B is a plot showing 0.2% creep and low cycle fatigue
(0.7% strain) data for alloy samples C and D of the invention and
for conventional alloy U720 LI; and
[0016] FIG. 1C is a plot showing 0.2% creep and low cycle fatigue
(0.9% strain) data for alloy samples C and D of the invention and
for conventional alloy U720 LI.
DETAILED DESCRIPTION OF THE INVENTION
[0017] The following detailed description is of the best currently
contemplated modes of carrying out the invention. The description
is not to be taken in a limiting sense, but is made merely for the
purpose of illustrating the general principles of the invention,
since the scope of the invention is best defined by the appended
claims.
[0018] The present invention provides nickel based superalloy
compositions useful for forming components for gas turbine engines,
such as compressor disks, turbine disks, disk seal plates and
spacers. The superalloy compositions of the present invention
differ from prior art nickel based superalloys (see, e.g., U.S.
Pat. No. 6,521,175 B1 to Mourer, et al.) in that alloys of the
invention, inter alia, contain tungsten (W) at concentrations
greater than 4.0% by weight, and typically have a W content equal
to or greater than about 4.25% by weight.
[0019] Compositions of the present invention exhibit fatigue crack
initiation life at intermediate temperatures (500 to 1200.degree.
F.) that are higher by about an order of magnitude as compared with
previously disclosed superalloy compositions. Alloys of the present
invention have superior low cycle fatigue (LCF) properties as
compared with previously disclosed nickel based superalloys. For
example, alloys of the present invention may have LCF life in
excess of 470,000 cycles at 1100.degree. F. and 0.7% strain.
Additionally, compositions of the present invention have superior
dwell crack growth resistance at higher temperatures (1200 to
1500.degree. F.), as compared with the current compositions U720
and Astroloy. Alloys of the present invention may exhibit 0.2%
creep values greater than about 400 hours at 1300.degree. F. and
100 ksi, and greater than about 50 hours at 1450.degree. F., and 65
ksi.
[0020] Alloy compositions of the present invention may be suitable
for forming gas turbine engine components, such as turbine discs
and exhibit resistance to the formation of harmful constituents
such as sigma phase when exposed to high temperatures (1300.degree.
F.+) for long periods of time. This latter property is commonly
known in the art as "stability". Compositions are selected within
the broad range based on proprietary calculations that predict
metallurgical stability. Alloy compositions of the present
invention enable turbine disk rim operating temperatures in excess
of 1400.degree. F., while providing a level of fatigue crack
initiation resistance at disk bore temperatures (typically 500 to
1100.degree. F.) at least equivalent to the highest known level of
fatigue crack initiation resistance attainable in previously
disclosed alloys having much lower high temperature capability as
compared with alloys of the invention.
[0021] Commonly assigned U.S. Pat. No. 6,468,368 B1 to Merrick, et
al., and commonly assigned US Patent Application Publication No.
2003/0079809 A1 also to Merrick, et al. disclose a nickel based
superalloy which contains 4.5 to 7.5 weight % (tungsten+rhenium),
the disclosures of which are incorporated by reference herein in
their entirety for all purposes.
[0022] Alloy compositions disclosed by Merrick et al. (U.S. Pat.
No. 6,468,368) exhibit strength and creep resistance as well as
stability at high temperatures (e.g., 1200 to 1500.degree. F.) (see
data for the sample designated as Alloy 1, FIGS. 1B-C). As will be
appreciated, nickel based superalloys which have similar, or the
same, components may have markedly different and unexpected
properties according to the proportion of the various components.
For example, the proportion of alloy components such as W, Nb, Mo,
Co, and Ta can have a major impact on the strength, creep
resistance, and crack initiation resistance of the alloy.
Applicants have now identified compositions having superior crack
growth and creep resistance at higher temperatures (1200 to
1500.degree. F.), and a high level of fatigue crack initiation
resistance at disk bore temperatures (typically 500 to 1100.degree.
F.), as compared with previously disclosed compositions.
[0023] Superalloy compositions of the present invention may be
produced by inert gas atomization, and consolidated by hot
isostatic pressing (HIP), or hot compaction. The material can be
used in HIP form, or may be extruded for forging stock to make
isothermally forged turbine engine disks or other components. Such
production processes are well known in the art.
[0024] In one embodiment of the invention, a nickel based
superalloy composition may comprise Ni, Co, Cr, Mo, W, Al, Ti, Ta,
Nb, C, B, and Zr, wherein W is greater than 4 weight %. More
particularly, the nickel based superalloy composition may comprise
from about 16.5 to about 20.5 weight % Co, about 9.5 to about 12.5
weight % Cr, about 1.8 to about 3.2 weight % Mo, about 4.25 to
about 6.0 weight % W, about 3.0 to about 4.2 weight % Al, about 3.0
to about 4.4 weight % Ti, about 1.0 to about 2.0 weight % Ta, about
0.06 to about 1.8 weight % Nb, about 0.01 to about 0.08 weight % C,
about 0.01 to about 0.06 weight % B, and about 0.03 to about 0.15
weight % Zr, balance Ni.
[0025] In an exemplary embodiment of the invention, the nickel
based superalloy composition comprises from about 16.8 to about
19.8 weight % Co, about 10.0 to about 12.0 weight % Cr, about 2.2
to about 3.0 weight % Mo, about 4.25 to about 5.5 weight % W, about
3.3 to about 3.9 weight % Al, about 3.3 to about 4.1 weight % Ti,
about 1.30 to about 1.8 weight % Ta, about 0.80 to about 1.60
weight % Nb, about 0.02 to about 0.05 weight % C, about 0.02 to
about 0.05 weight % B, and about 0.05 to about 0.12 weight % Zr,
balance Ni.
[0026] In a first more preferred embodiment of the invention a
nickel based superalloy composition, which may be designated Alloy
1.1, comprises from about 17.8 to about 19.8 weight % Co, about
10.0 to about 12.0 weight % Cr, about 2.3 to about 2.9 weight % Mo,
about 4.25 to about 5.0 weight % W, about 3.3 to about 3.8 weight %
Al, about 3.5 to about 4.0 weight % Ti, about 1.3 to about 1.8
weight % Ta, about 0.90 to about 1.60 weight % Nb, about 0.02 to
about 0.050 weight % C, about 0.02 to about 0.040 weight % B, and
about 0.05 to about 0.10 weight % Zr, balance Ni. The nickel based
superalloy composition designated Alloy 1.1 may exhibit a LCF life
at 800.degree. F., R=-1, 0.65% strain, of greater than about
260,000 cycles.
EXAMPLE 1
[0027] As an example of Alloy 1.1, the nickel based superalloy
composition includes about 18.5 weight % Co, about 11 weight % Cr,
about 3.55 weight % Al, about 2.6 weight % Mo, about 4.6 weight %
W, about 3.75 weight % Ti, about 1.5 weight % Ta, about 0.90 to
about 1.60 weight % Nb, about 0.03 weight % C, about 0.03 weight %
B, and about 0.075 weight % Zr, balance Ni. For this alloy (1.1),
it is of importance to note that Co content may be increased to
levels as high as about 20% in order to reduce solvus temperature
without adversely affecting stability and properties. The mean Co
content of such a reduced solvus version of Alloy 1.1 may be about
19.25. Reduced solvus temperature may be useful for improving ease
of processing for certain applications.
[0028] In a second more preferred embodiment of the invention,
which may be designated Alloy 1.2, a nickel based superalloy
composition comprises from about 16.8 to about 17.2 weight % Co,
about 10.5 to about 12 weight % Cr, about 2.4 to about 2.8 weight %
Mo, about 5.1 to about 5.5 weight % W, about 3.4 to about 3.8
weight % Al, about 3.6 to about 4.0 weight % Ti, about 1.3 to about
1.7 weight % Ta, about 0.85 to about 1.15 weight % Nb, about 0.02
to about 0.05 weight % C, about 0.020 to about 0.040 weight % B,
and about 0.05 to about 0.10 weight % Zr, balance Ni. This
embodiment is less preferred than the first preferred embodiment.
The nickel based superalloy composition designated Alloy 1.2 may
exhibit a LCF life at 1100.degree. F., R=0, 0.7% strain, of greater
than about 470,000 cycles. Alloy 1.2 may further exhibit a time for
0.2% creep, at 1300.degree. F. and 100 ksi, of greater than about
400 hours, in fine grain form.
EXAMPLE 2
[0029] As an example of Alloy 1.2, the nickel based superalloy
composition includes about 17 weight % Co, about 11.25 weight % Cr,
about 3.6 weight % Al, about 2.55 weight % Mo, about 5.3 weight %
W, about 3.8 weight % Ti, about 1.5 weight % Ta, about 1.0 weight %
Nb, about 0.03 weight % C, about 0.03 weight % B, and about 0.075
weight % Zr, balance Ni.
[0030] The embodiment of the invention generally corresponding to
Alloy 1.1 has the characteristics of ease of producibility, and has
a reduced solvus temperature, due to increased Co content, as
compared with Alloy 1.2. Alloy 1.2 may have increased high
temperature creep and crack growth resistance capability, as
compared with Alloy 1.1. In light of the differences in properties
and composition of Alloy 1.1 (e.g., Sample B, Alloy 1.1B) in
comparison with that of Alloy 1.2 (e.g., Sample C, Alloy 1.2C), one
skilled in the art may recognize how to formulate compositions
exhibiting variations of such properties. The composition and
performance characteristics of a nickel based superalloy designated
Sample D (Alloy 1.3), which is intermediate between Alloy 1.1 and
Alloy 1.2 with respect to its content of C, Cr, Co, Nb, Al, and B,
is described in Example 3, according to one embodiment of the
invention.
[0031] An alloy having a composition intermediate between those of
Alloys 1.1 and 1.2 (e.g., Alloy 1.3 (Example 3)) may comprise about
17.4 weight % Co, about 11.0 weight % Cr, about 2.56 weight % Mo,
about 5.5 weight % W, about 3.64 weight % Al, about 3.8 weight %
Ti, about 1.47 weight % Ta, about 0.94 weight % Nb, about 0.03
weight % C, about 0.03 weight % B, and about 0.1 weight % Zr,
balance Ni. A superalloy such as Alloy 1.3 may exhibit a LCF life,
at 1100.degree. F. and 0.7% strain, of greater than about 200,000
cycles.
[0032] In one embodiment, nickel based superalloy compositions of
the present invention may be formed by the Powder Metallurgy (P/M)
route, for example, as described in commonly assigned U.S. Pat. No.
6,468,368 B1 to Merrick, et al., the disclosure of which is
incorporated by reference herein in its entirety for all
purposes.
[0033] In some embodiments, nickel based superalloy compositions of
the present invention may optionally further include rhenium in an
amount from 0 to about 2.0 weight %, and usually at or near 0
weight %. Generally, rhenium may have little or no effect on
superalloy properties, but may result in a slight enhancement of
creep performance.
[0034] In some embodiments, nickel based superalloy compositions of
the present invention may optionally further include hafnium in an
amount from 0 to about 1.0 weight %, although amounts greater than
0% may have a negative impact on LCF properties, as seen in some
prior art superalloys. Additional elements, such as magnesium (up
to 0.1 weight %), may also be added to superalloy compositions of
the invention, typically with no substantial effect on
properties.
EXAMPLE 3
[0035] An alloy of the invention designated Sample B (Alloy 1.1B)
was prepared having the following composition expressed as weight
%: about 18.2% Co, about 11.2% Cr, about 2.65% Mo, about 4.8% W,
about 3.57% Al, about 3.86% Ti, about 1.65% Ta, about 0.95% Nb,
about 0.027% C, about 0.028% B, and about 0.07% Zr, balance Ni. A
conventional alloy (Astroloy) was also prepared, and the fatigue
and creep characteristics of HIP processed Sample B and Astroloy
were compared. For both the Astroloy and Sample B alloy, 270 mesh
powder was used. Both the Astroloy and Sample B were supersolvus
HIP processed at about 2215.degree. F., and solution treated to
yield a grain size of ASTM 7 to 8. The cooling rate was about
75.degree. F. per minute from solution treatment temperature for
both Astroloy and Sample B.
[0036] The data for LCF life at 800.degree. F., R=-1, 0.65% strain,
and time for 0.2% creep at 1450.degree. F., 65 ksi for conventional
Astroloy and Sample B of the invention are shown in FIG. 1A. Under
these conditions the conventional material, Astroloy, had a LCF of
166,810 cycles. In comparison, Sample B (Alloy 1.1B) of the
invention had a LCF of 266,154 cycles. Similarly, the conventional
material, Astroloy, showed a time for 0.2% creep at 1450.degree. F.
and 65 ksi of five (5) hours. In comparison, Sample B (Alloy 1.1B)
of the invention exhibited a time for 0.2% creep at 1450.degree. F.
and 65 ksi of 85 hours. The data from FIG. 1A is tabulated below
(Table 1).
1TABLE 1 LCF and 0.2% Creep Values for Sample B and PM Astroloy
Time (hours) for LCF Life (cycles) 0.2% Creep (1450.degree.
(800.degree. F., R = Alloy Material F., 65 ksi) -1, 0.65% strain)
Sample B 85 266,154 PM Astroloy.sup.1 5 166,810 .sup.1conventional
superalloy
EXAMPLE 4
[0037] An alloy of the invention designated Sample A (Alloy 1.1A)
was prepared having the following composition expressed as weight
%: about 17.8% Co, about 11.0% Cr, about 2.6% Mo, about 5.0% W,
about 3.58% Al, about 3.9% Ti, about 1.47% Ta, about 1.03% Nb,
about 0.028% C, about 0.028% B, and about 0.10% Zr, balance Ni. The
fatigue and creep characteristics of HIP processed Sample A were
generally similar to those of HIP processed Sample B as described
hereinabove (Example 3 and FIG. 1A).
EXAMPLE 5
[0038] An alloy of the invention designated Sample C (Alloy 1.2C)
was prepared having the following composition expressed as weight
%: about 16.9% Co, about 11.1% Cr, about 2.55% Mo, about 5.5% W,
about 3.79% Al, about 3.97% Ti, about 1.57% Ta, about 0.91% Nb,
about 0.033% C, about 0.035% B, and about 0.09% Zr, balance Ni.
Sample C was made from 270 mesh powder, hot compacted, extruded,
and isothermally forged. The test material was subsolvus solution
treated to yield a grain size of ASTM 11-12. The cooling rate from
solution temperature was about 130.degree. F. per minute.
EXAMPLE 6
[0039] A further alloy of the invention, designated Sample D (Alloy
1.3), was prepared having the following composition expressed as
weight %: about 17.4% Co, about 11.0% Cr, about 2.56% Mo, about
5.5% W, about 3.64% Al, about 3.8% Ti, about 1.47% Ta, about 0.94%
Nb, about 0.03% C, about 0.03% B, and about 0.1% Zr, balance Ni.
Sample D was made from 270 mesh powder, hot compacted, extruded and
isothermally forged. The solution treatment was subsolvus to yield
a grain size of ASTM 10-11. The cooling rate from solution
temperature was about 500.degree. F. per minute.
[0040] The data for low cycle fatigue (LCF) life at 1100.degree.
F., R=0, 0.7% strain, and time for 0.2% creep at 1300.degree. F.,
100 ksi, for Samples C and D of the invention are shown in FIG. 1B.
For comparison, conventional alloy U720 LI was tested under the
same conditions. Alloy 1 represents an alloy composition according
to commonly assigned U.S. Pat. No. 6,468,368 B1 to Merrick et al.
Samples C and D of the invention had a LCF life of 472,876 cycles
and 205,610 cycles, respectively; and a time for 0.2% creep at
1300.degree. F. and 100 ksi of 432 hours and 450 hours,
respectively.
[0041] Under these conditions, LCF values for Samples C and D,
respectively, are almost five times (5.times.) and more than twice
(>2.times.) the LCF value for conventional alloy U720 LI. Time
for 0.2% creep for Samples C and D of the invention is about two
(2) orders of magnitude greater than that for conventional alloy
720. It can also be seen from FIG. 1B that under the specified test
conditions, LCF values and time for 0.2% creep for Samples C and D
are at least several fold higher than those for Alloy 1.
[0042] Data for LCF life at 1100.degree. F., R=0, 0.9% strain for
Samples C and D of the invention (Examples 5 and 6) are shown in
FIG. 1C. Data for the conventional alloy, U720 LI, and for Alloy 1,
tested under the same conditions, are included for comparison. It
can be seen from FIG. 1C that under the specified test conditions,
LCF values and time for 0.2% creep for Samples C and D are at least
several fold higher than those for alloy U720 LI and Alloy 1. The
data from FIGS. 1B and 1C are tabulated below (Table 2).
2TABLE 2 LCF and 0.2% Creep Values for Various Superalloys Time
(hours) for LCF Life (cycles) LCF Life (cycles) Alloy 0.2% Creep
(1300.degree. (1100.degree. F., R = (1100.degree. F., R = Material
F., 100 ksi) 0, 0.7% strain) 0, 0.9% strain) Sample C 432 472,876
221,776 Sample D 450 205,610 61,860 U720 LI.sup.2 5 95,911 7,263
Alloy 1.sup.3 85 66,550 9,850 .sup.2conventional superalloy;
.sup.3alloy of Merrick et al. (U.S. Pat. No. 6,468,368).
[0043] It should be understood, of course, that the foregoing
relates to embodiments of the invention and that modifications may
be made without departing from the spirit and scope of the
invention as set forth in the following claims.
* * * * *