U.S. patent number RE40,501 [Application Number 11/077,572] was granted by the patent office on 2008-09-16 for nickel-base superalloys and articles formed therefrom.
This patent grant is currently assigned to General Electric Company. Invention is credited to John Joseph deBarbadillo, II, Michael Francis Henry, Sarwan Kumar Mannan, Elena Rozier, Samuel Vinod Thamboo.
United States Patent |
RE40,501 |
Henry , et al. |
September 16, 2008 |
**Please see images for:
( Certificate of Correction ) ** |
Nickel-base superalloys and articles formed therefrom
Abstract
An article, such as a turbine engine component, formed from a
nickel-base superalloy, the nickel-base superalloy containing a
.gamma.'' tetragonal phase and comprising aluminum, titanium,
tantalum, niobium, chromium, molybdenum, and the balance nickel,
wherein the article has a time dependent crack propagation
resistance of at least about 20 hours to failure at about
1100.degree. F. in the presence of steam. The invention also
includes a nickel-base superalloy for forming such and article and
methods of forming the article and making the nickel-base
superalloy.
Inventors: |
Henry; Michael Francis
(Niskayuna, NY), Rozier; Elena (Niskayuna, NY), Thamboo;
Samuel Vinod (Latham, NY), Mannan; Sarwan Kumar
(Barboursville, WV), deBarbadillo, II; John Joseph
(Barboursville, WV) |
Assignee: |
General Electric Company
(Schenectady, NY)
|
Family
ID: |
25284586 |
Appl.
No.: |
11/077,572 |
Filed: |
March 10, 2005 |
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
Reissue of: |
09841326 |
Apr 24, 2001 |
06531002 |
Mar 11, 2003 |
|
|
Current U.S.
Class: |
148/409; 148/428;
420/448 |
Current CPC
Class: |
C22C
19/055 (20130101); C22C 19/058 (20130101); C22C
19/056 (20130101) |
Current International
Class: |
C22C
19/05 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
2270324 |
|
Mar 1994 |
|
GB |
|
59-211560 |
|
Nov 1984 |
|
JP |
|
Other References
"Nickel, Cobalt, and Their Alloys", pub. ASM International, 2000
(no month), pp. 69-77, 82-83, 233-234 and 302-303. cited by
examiner.
|
Primary Examiner: Wilkins, III; Harry D
Attorney, Agent or Firm: McNees Wallace & Nurick LLC
Claims
What is claimed is:
1. An article formed from a nickel-base superalloy, said
nickel-base superalloy containing a .gamma.'' tetragonal phase and
comprising: between about 0.05 and about 2.0 weight percent
aluminum; from about 1.5 to about 5 weight percent cobalt; between
about 15 and about 25 weight percent chromium; up to about 40
weight percent iron; from about 6 to about 12 weight percent
molybdenum; between about 2 and about 7 weight percent niobium;
from about 2 to about 3 weight percent tantalum; up to about 2.5
weight percent titanium; and the balance nickel, wherein said
article has a time dependent crack propagation resistance of at
least about 20 hours to failure at about 1100.degree. F. in the
presence of steam.
2. The article of claim 1, wherein said article has a yield
strength of greater than 130 ksi at about 750.degree. F.
3. The article of claim 2, wherein said article has a yield
strength of greater than 146 ksi at about 750.degree. F.
4. The article of claim 3, wherein said yield strength is at least
160 ksi at about 750.degree. F.
5. The article of claim 1, further comprising cobalt.
6. The article of claim 1, wherein said nickel-base superalloy
comprises: between about 0.1 and about 0.6 weight percent aluminum;
from about 1.5 to about 5 weight percent cobalt; between about 19
and about 22 weight percent chromium; up to about 8.0 weight
percent iron; between about 6 and about 9 weight percent
molybdenum; between at least 3.5 and about 5.1 weight percent
niobium; from about 2 to about 3 weight percent tantalum; between
about 0.6 and about 2.0 weight percent titanium; and a balance of
nickel.
7. The article of claim 6, wherein said nickel-base superalloy
comprises: between about 0.1 and about 0.5 weight percent aluminum;
from about 1.5 to about 5 weight percent cobalt; between about 19
and about 21 weight percent chromium; about 8.0 weight percent
iron; between about 6 and about 9 weight percent molybdenum;
between at least 3.5 and about 5.1 weight percent niobium; from
about 2 to about 3 weight percent tantalum; between about 0.8 and
about 1.0 weight percent titanium; and a balance of nickel.
8. The article of claim 7, wherein said nickel-base superalloy
comprises: about 0.5 weight percent aluminum; about 5 weight
percent cobalt; about 19 weight percent chromium; about 8 weight
percent iron; about 6.4 weight percent molybdenum; about 3.5 weight
percent niobium; about 3 weight percent tantalum; about 1.0 weight
percent titanium; and a balance of nickel.
9. The article of claim 1, wherein said nickel-base superalloy
comprises: between about 0.2 and about 0.6 weight percent aluminum;
from about 1.5 to about 5 weight percent cobalt; between about 19
and about 22 weight percent chromium; up to about 8.0 weight
percent iron; between about 6 and about 9 weight percent
molybdenum; between at least 3.6 and about 5.5 weight percent
niobium; from about 2 to about 3 weight percent tantalum; between
about 0.6 and about 2.0 weight percent titanium; and a balance of
nickel.
10. The article of claim 9, wherein said nickel-base superalloy
comprises: between about 0.2 and about 0.6 weight percent aluminum;
from about 1.5 to about 5 weight percent cobalt; about 21.5 weight
percent chromium; about 2.5 weight percent iron; about 9 weight
percent molybdenum; between at least 3.6 and about 5.5 weight
percent niobium; from about 2 to about 3 weight percent tantalum;
between about 0.6 and about 2.0 weight percent titanium; and a
balance of nickel.
11. The article of claim 10, wherein said nickel-base superalloy
comprises: about 0.5 weight percent aluminum; from about 1.5 to
about 5 weight percent cobalt; about 21.5 weight percent chromium;
about 2.5 weight percent iron; about 9 weight percent molybdenum;
about 5.1 weight percent niobium; from about 2 to about 3 weight
percent tantalum; about 0.9 weight percent titanium; and a balance
of nickel.
12. The article of claim 1, wherein said nickel-base superalloy
further comprises: at least one element selected from the group
consisting of tungsten, rhenium, and vanadium.
13. The article of claim 12, wherein said nickel-base superalloy
further comprises up to about 3 weight percent tungsten.
14. The article of claim 12, wherein said nickel-base superalloy
further comprises up to about 3 weight percent rhenium.
15. .[.A.]. The article of claim 12, wherein said nickel-base
superalloy further comprises up to about 1 weight percent
vanadium.
16. The article of claim 1, wherein said nickel-base superalloy
further comprises at least one element selected from the group
consisting of carbon, manganese, magnesium, boron, silicon, and
zirconium.
17. The article of claim 1, wherein said article has a crack
propagation resistance of at least 200 hours to failure at about
1100.degree. F. in the presence of steam.
18. The article of claim 1, wherein said article is a turbine
engine component.
19. The article of claim 18, wherein said turbine engine component
is a component selected from the group consisting of compressor
rotors, compressor vanes, compressor stators, combustor cans,
nozzles, turbine discs, turbine wheels, and buckets.
20. The article of claim 18, wherein said turbine engine component
is a component in a land-based turbine engine.
21. The article of claim 18, wherein said turbine engine component
is a component in an aircraft turbine engine.
22. A nickel-base superalloy for forming an article, said
nickel-base superalloy containing a .gamma.'' tetragonal phase and
comprising: between about 0.05 and about 2.0 weight percent
aluminum; from about 1.5 to about 5 weight percent cobalt; between
about 15 and about 25 weight percent chromium; up to about 40
weight percent iron; from about 6 to about 12 weight percent
molybdenum; between about 2 and about 7 weight percent niobium;
from about 2 to about 3 weight percent tantalum; up to about 2.5
weight percent titanium; and the balance nickel, wherein said
nickel-base superalloy has a crack propagation resistance of at
least 20 hours to failure at about 1100.degree. F. in the presence
of steam and a yield strength of greater than 130 ksi at about
750.degree. F.
23. The nickel-base superalloy of claim 22, wherein said
nickel-base superalloy has a yield strength of greater than 146 ksi
at about 750.degree. F.
24. The nickel-base superalloy of claim 22, wherein said yield
strength is at least 160 ksi at about 750.degree. F.
25. The nickel-base superalloy of claim 22, wherein said crack
propagation resistance is at least 200 hours to failure at about
1100.degree. F. in the presence of steam.
26. The nickel-base superalloy of claim 22, wherein said
nickel-base superalloy comprises: between about 0.1 and about 0.6
weight percent aluminum; from about 1.5 to about 5 weight percent
cobalt; between about 19 and about 22 weight percent chromium; up
to about 8.0 weight percent iron; between about 6 and about 9
weight percent molybdenum; from 3.5 to about 5.1 weight percent
niobium; from about 2 to about 3 weight percent tantalum; between
about 0.6 and about 2.0 weight percent titanium; and a balance of
nickel.
27. The nickel-base superalloy of claim 26, wherein said
nickel-base superalloy comprises: between about 0.1 and about 0.5
weight percent aluminum; from about 1.5 to about 5 weight percent
cobalt; between about 19 and about 21 weight percent chromium;
about 8.0 weight percent iron; between about 6 and about 9 weight
percent molybdenum; between at least 3.5 and about 5.1 weight
percent niobium; from about 2 to about 3 weight percent tantalum;
between about 0.8 and about 1.0 weight percent titanium; and a
balance of nickel.
28. The nickel-base superalloy of claim 27, wherein said
nickel-base superalloy comprises: about 0.5 weight percent
aluminum; about 5 weight percent cobalt; about 19 weight percent
chromium; about 8 weight percent iron; about 6.4 weight percent
molybdenum; about 3.5 weight percent niobium; about 3 weight
percent tantalum; about 1.0 weight percent titanium; and a balance
of nickel.
29. The nickel-base superalloy of claim 22, wherein said
nickel-base superalloy comprises: between about 0.2 and about 0.6
weight percent aluminum; from about 1.5 to about 5 weight percent
cobalt, between about 19 and about 22 weight percent chromium; up
to about 8.0 weight percent iron; between about 6 and about 9
weight percent molybdenum; between at least 3.6 and about 5.5
weight percent niobium; from about 2 to about 3 weight percent
tantalum; between about 0.6 and about 2.0 weight percent titanium;
and a balance of nickel.
30. The nickel-base superalloy of claim 29, wherein said
nickel-base superalloy comprises: between about 0.2 and about 0.6
weight percent aluminum; from about 1.5 to about 5 weight percent
cobalt; about 21.5 weight percent chromium; about 2.5 weight
percent iron; about 9 weight percent molybdenum; between at least
3.6 and about 5.5 weight percent niobium; from about 2 to about 3
weight percent tantalum; between about 0.6 and about 2.0 weight
percent titanium; and a balance of nickel.
31. The nickel-base superalloy of claim 30, wherein said
nickel-base superalloy comprises: about 0.5 weight percent
aluminum; from about 1.5 to about 5 weight percent cobalt; about
21.5 weight percent chromium; about 2.5 weight percent iron; about
9 weight percent molybdenum; about 5.1 weight percent niobium; from
about 2 to about 3 weight percent tantalum; about 0.9 weight
percent titanium; and a balance of nickel.
32. An article formed from a nickel-base superalloy, the
nickel-base superalloy containing a .gamma.'' tetragonal phase and
comprising between about 0.05 and about 2.0 weight percent
aluminum; from about 1.5 to about 5 weight percent cobalt; between
about 15 and about 25 weight percent chromium; up to about 40
weight percent iron; from about 6 to about 12 weight percent
molybdenum; between about 2 and about 7 weight percent niobium;
from about 2 to about 3 weight percent tantalum; up to about 2.5
weight percent titanium; and the balance nickel, wherein said
article has a time dependent crack propagation resistance of at
least 20 hours to failure at about 1100.degree. F. in the presence
of steam and a yield strength of greater than 130 ksi at about
750.degree. F.
33. The article of claim 32, wherein said article has a yield
strength of greater than 146 ksi at about 750.degree. F.
34. The article of claim 32, wherein said yield strength is at
least 160 ksi at about 750.degree. F.
35. The article of claim 32, wherein said crack propagation
resistance is least 200 hours to failure at about 1100.degree. F.
in the presence of steam.
36. The article of claim 32, wherein said nickel-base superalloy
comprises: between about 0.1 and about 0.6 weight percent aluminum;
from about 1.5 to about 5 weight percent cobalt; between about 19
and about 22 weight percent chromium; up to about 8.0 weight
percent iron; between about 6 and about 9 weight percent
molybdenum; between at least 3.5 and about 5.1 weight percent
niobium; from about 2 to about 3 weight percent tantalum; between
about 0.6 and about 2.0 weight percent titanium; and a balance of
nickel.
37. The article of claim 36, wherein said nickel-base superalloy
comprises: between about 0.1 and about 0.5 weight percent aluminum;
from about 1.5 to about 5 weight percent cobalt; between about 19
and about 21 weight percent chromium; about 8.0 weight percent
iron; between about 6 and about 9 weight percent molybdenum;
between at least 3.5 and about 5.1 weight percent niobium; from
about 2 to about 3 weight percent tantalum; between about 0.8 and
about 1.0 weight percent titanium; and a balance of nickel.
38. The article of claim 37, wherein said nickel-base superalloy
comprises: about 0.5 weight percent aluminum; about 5 weight
percent cobalt; about 19 weight percent chromium; about 8 weight
percent iron; about 6.4 weight percent molybdenum; about 3.5 weight
percent niobium; about 3 weight percent tantalum; about 1.0 weight
percent titanium; and a balance of nickel.
39. The article of claim 36, wherein said nickel-base superalloy
comprises: between about 0.2 and about 0.6 weight percent aluminum;
from about 1.5 to about 5 weight percent cobalt; between about 19
and about 22 weight percent chromium; up to about 8.0 weight
percent iron; between about 6 and about 9 weight percent
molybdenum; between at least 3.6 and about 5.5 weight percent
niobium; from about 2 to about 3 weight percent tantalum; between
about 0.6 and about 2.0 weight percent titanium; and a balance of
nickel.
40. The article of claim 39, wherein said nickel-base superalloy
comprises: between about 0.2 and about 0.6 weight percent aluminum;
from about 1.5 to about 5 weight percent cobalt; about 21.5 weight
percent chromium; about 2.5 weight percent iron; about 9 weight
percent molybdenum; between at least 3.6 and about 5.5 weight
percent niobium; from about 2 to about 3 weight percent tantalum;
between about 0.6 and about 2.0 weight percent titanium; and a
balance of nickel.
41. The article of claim 40, wherein said nickel-base superalloy
comprises: about 0.5 weight percent aluminum; from about 1.5 to
about 5 weight percent cobalt; about 21.5 weight percent chromium;
about 2.5 weight percent iron; about 9 weight percent molybdenum;
about 5.1 weight percent niobium; from about 2 to about 3 weight
percent tantalum; about 0.9 weight percent titanium; and a balance
of nickel.
42. The article of claim 32, wherein said nickel-base superalloy
further comprises at least one element selected from the group
consisting of tungsten, rhenium, and vanadium.
43. The article of claim 42, wherein said nickel-base superalloy
further comprises up to about 3 weight percent tungsten.
44. .[.A.]. The article of claim 42, wherein said nickel-base
superalloy further comprises up to about 3 weight percent
rhenium.
45. The article of claim 42, wherein said nickel-base superalloy
further comprises up to about 1 weight percent vanadium.
46. The article of claim 32, wherein said article is a turbine
engine component.
47. The article of claim 46, wherein said turbine engine component
is a component selected from the group consisting of compressor
rotors, compressor vanes, compressor stators, combustor cans,
nozzles, turbine discs, turbine wheels, and buckets.
48. The article of claim 46, wherein said turbine engine component
is a component in a land-based turbine engine.
49. The article of claim 46, wherein said turbine engine component
is a component in an aircraft turbine engine.
50. An article formed from a nickel-base superalloy, said
nickel-base superalloy containing a .gamma.'' tetragonal phase and
comprising: between about 0.05 and about 2.0 weight percent
aluminum; from about 1.5 to about 5 weight percent cobalt; between
about 15 and about 25 weight percent chromium; up to about 40
weight percent iron; from about 6 to about 12 weight percent
molybdenum; between about 2 and about 7 weight percent niobium;
from about 2 to about 3 weight percent tantalum; up to about 2.5
weight percent titanium; and the balance nickel, wherein said
article has a time dependent crack propagation resistance of at
least about 20 hours to failure at about 1100.degree. F. in the
presence of steam, and wherein said article is formed by: forming
an ingot of the nickel-base superalloy; remelting the ingot a first
time; remelting the ingot a second time; homogenizing the ingot by
heat treating the ingot at a first temperature below a melting
temperature of the nickel-base superalloy; billetizing the ingot,
thereby creating a billet; hot-working the billet; and solution
treating the billet at a second temperature below a solvus
temperature of a high temperature phase of the superalloy to form
the nickel-base superalloy article.
51. The article of claim 50, wherein the second temperature is
below a .delta.-solvus temperature of the nickel-base
superalloy.
52. The article of claim 50, wherein said article is a turbine
engine component.
53. The article of claim 52, wherein said turbine engine component
is a component selected from the group consisting of compressor
rotors, compressor vanes, compressor stators, combustor cans,
nozzles, turbine discs, turbine wheels, and buckets.
54. The article of claim 52, wherein said turbine engine component
is a component in a land-based turbine engine.
55. The article of claim 52, wherein said turbine engine component
is a component in an aircraft turbine engine.
56. The article of claim 52, wherein said article has a diameter of
at least about 20 inches.
57. A nickel-base superalloy, said nickel-base superalloy
containing a .gamma.'' tetragonal phase and comprising: between
about 0.05 and about 2.0 weight percent aluminum; from about 1.5 to
about 5 weight percent cobalt; between about 15 and about 25 weight
percent chromium; up to about 40 weight percent iron; from about 6
to about 12 weight percent molybdenum; between about 2 and about 7
weight percent niobium; from about 2 to about 3 weight percent
tantalum; up to about 2.5 weight percent titanium; and the balance
nickel, wherein said nickel-base superalloy has a time dependent
crack propagation resistance of at least about 20 hours to failure
at about 1100.degree. F. in the presence of steam, and wherein said
nickel-base superalloy is formed by: forming an ingot of the
nickel-base superalloy; remelting the ingot a first time; remelting
the ingot a second time; homogenizing the ingot to a first
temperature below a melting temperature of the nickel-base
superalloy; billetizing the ingot, thereby creating a billet;
hot-working the billet; and solution treating the billet at a
second temperature below a solvus temperature of a high temperature
phase of the superalloy.
58. The nickel-base alloy of claim 57, wherein the second
temperature is below a .delta.-solvus temperature of the
nickel-base superalloy.
.Iadd.59. A turbine engine component formed from a nickel-base
superalloy, the nickel-base superalloy including a .gamma.''
tetragonal phase, the nickel-base superalloy comprising, in weight
percent: between about 0.05 and about 0.5 percent aluminum, cobalt
is present and is present in a concentration up to about 5 percent,
between about 19 and 22 percent chromium, up to about 8 percent
iron, between about 6 and about 9 percent molybdenum, between about
3.3 and about 5.4 percent niobium, tantalum is present and is
present in a concentration of up to 3 percent, between about 0.2
and about 1.6 percent titanium and the balance nickel; and wherein
the nickel-base superalloy comprising the turbine engine component
has a crack propagation resistance of at least about 200 hours to
failure at 1100.degree. F. in the presence of steam and a yield
strength of at least about 130 ksi at a temperature of 750.degree.
F..Iaddend.
.Iadd.60. The turbine engine component of claim 59 wherein the
nickel-base superalloy comprises: about 0.5 percent aluminum, about
21.5 percent chromium, about 2.5 percent iron, about 9 percent
molybdenum, about 5.1 percent niobium about 0.9 percent titanium
and the balance nickel; wherein the nickel-base superalloy
comprising the engine component has a crack propagation resistance
of at least about 1680 hours to failure at 1100.degree. F. in the
presence of steam; and wherein the nickel-base superalloy
comprising the engine component has a yield strength of at least
about 160 ksi at a temperature of 750.degree. F., a room
temperature yield strength of at least about 177 ksi and a room
temperature ultimate tensile strength of at least about 221
ksi..Iaddend.
.Iadd.61. The turbine engine component of claim 60 wherein the
.gamma.'' tetragonal phase providing the crack propagation
resistance at 1100.degree. F., the yield strength at 750.degree.
F., the room temperature yield strength and the room temperature
ultimate tensile strength is achieved by first homogenizing the
nickel-base superalloy, then shaping the superalloy at a
temperature below the homogenization temperature, then solutioning
the shaped superalloy at a temperature below a .delta.-solvus
temperature or Laves solvus temperature of the shaped superalloy to
partially solution the shaped superalloy to precipitate in a matrix
the phase that is primarily .gamma.'' tetragonal..Iaddend.
.Iadd.62. The turbine engine component of claim 59 wherein the
nickel-base superalloy comprises: about 0.5 percent aluminum, about
21.5 percent chromium, about 2.5 percent iron, about 9 percent
molybdenum, about 5.1 percent niobium about 0.9 percent titanium
and the balance nickel; wherein the nickel-base superalloy
comprising the engine component has a crack propagation resistance
of at least about 1680 hours to failure at 1100.degree. F. in the
presence of steam; and wherein the nickel-base superalloy
comprising the engine component has a grain size of less than about
5 microns..Iaddend.
.Iadd.63. The turbine engine component of claim 62 wherein the
.gamma.'' tetragonal phase providing the crack propagation
resistance at 1100.degree. F., and grain size is achieved by first
homogenizing the nickel-base superalloy, then shaping the
superalloy at a temperature below the homogenization temperature,
then solutioning the shaped superalloy at a temperature below a
.delta.-solvus temperature or Laves solvus temperature of the
shaped superalloy to partially solution the shaped superalloy to
precipitate in a matrix the phase that is primarily .gamma.''
tetragonal..Iaddend.
.Iadd.64. A turbine engine component formed from a nickel-base
superalloy, said nickel-base superalloy including a .gamma.''
tetragonal phase, the nickel-base superalloy comprising, in weight
percent, about 0.5 percent aluminum, cobalt is present, about 19
percent chromium, about 18.5 percent iron, about 3 percent
molybdenum, about 5.1 percent niobium, about 0.9 percent titanium,
tantalum is present and is present in a concentration of up to
about 3 percent and the balance nickel; wherein the nickel-base
superalloy comprising the engine component has a crack propagation
resistance of at least about 200 hours to failure at 1100.degree.
F. in the presence of steam; and wherein the nickel-base superalloy
comprising the engine component has a yield strength of at least
about 146 ksi at a temperature of 750.degree. F., a room
temperature yield strength of at least about 164 ksi and a room
temperature ultimate tensile strength of about 212
ksi..Iaddend.
.Iadd.65. The turbine engine component of claim 64 wherein the
.gamma.'' tetragonal phase providing the crack propagation
resistance at 1100.degree. F., the yield strength at 750.degree.
F., the room temperature yield strength and the room temperature
ultimate tensile strength is achieved by first homogenizing the
nickel-base superalloy, then shaping the superalloy at a
temperature below the homogenization temperature, then solutioning
the shaped superalloy at a temperature below a .delta.-solvus
temperature or Laves solvus temperature of the shaped superalloy to
partially solution the shaped superalloy to precipitate in a matrix
the phase that is primarily .gamma.'' tetragonal..Iaddend.
.Iadd.66. A turbine engine component formed from a nickel-base
superalloy, said nickel-base superalloy including a .gamma.''
tetragonal phase, the nickel-base superalloy comprising, in weight
percent: about 0.5 percent aluminum, cobalt is present, about 19
percent chromium, about 18.5 percent iron, about 3 percent
molybdenum, about 5.1 percent niobium, about 0.9 percent titanium,
tantalum is present and is present in a concentration of up to 3
percent and the balance nickel; wherein the nickel-base superalloy
comprising the engine component has a crack propagation resistance
of at least about 200 hours to failure at 1100.degree. F. in the
presence of steam and a yield strength of at least about 130 ksi at
a temperature of 750.degree. F.; and wherein the nickel-base
superalloy comprising the engine component has a grain size of less
than about 5 microns..Iaddend.
.Iadd.67. The turbine engine component of claim 66 wherein the
.gamma.'' tetragonal phase providing the crack propagation
resistance at 1100.degree. F., and the grain size is achieved by
first homogenizing the nickel-base superalloy, then shaping the
superalloy at a temperature below the homogenization temperature,
then solutioning the shaped superalloy at a temperature below a
.delta.-solvus temperature or Laves solvus temperature of the
shaped superalloy to partially solution the shaped superalloy to
precipitate in a matrix the phase that is primarily .gamma.''
tetragonal..Iaddend.
.Iadd.68. A turbine engine component formed from a nickel-base
superalloy, said nickel-base superalloy including a .gamma.''
tetragonal phase, the nickel-base superalloy comprising, in weight
percent: about 0.09 percent aluminum, cobalt is present, about 20.9
percent chromium, about 7.91 percent iron, about 7.92 percent
molybdenum, about 3.48 percent niobium, about 1.57 percent
titanium, tantalum is present and is present in a concentration of
up to 3 percent and the balance nickel; wherein the nickel-base
superalloy comprising the engine component has a crack propagation
resistance of at least about 2139 hours to failure at 1100.degree.
F. in the presence of steam; and wherein the nickel-base superalloy
comprising the engine component has a yield strength of at least
about 163 ksi at a temperature of 750.degree. F., a room
temperature yield strength of at least about 177 ksi and a room
temperature ultimate tensile strength of at least about 220
ksi..Iaddend.
.Iadd.69. The turbine engine component of claim 68 wherein the
.gamma.'' tetragonal phase providing the crack propagation
resistance at 1100.degree. F., the yield strength at 750.degree.
F., the room temperature yield strength and the room temperature
ultimate tensile strength is achieved by first homogenizing the
nickel-base superalloy, then shaping the superalloy at a
temperature below the homogenization temperature, then solutioning
the shaped superalloy at a temperature below a .delta.-solvus
temperature or Laves solvus temperature of the shaped superalloy to
partially solution the shaped superalloy to precipitate in a matrix
the phase that is primarily .gamma.'' tetragonal..Iaddend.
.Iadd.70. A turbine engine component formed from a nickel-base
superalloy, said nickel-base superalloy including a .gamma.''
tetragonal phase, the nickel-base superalloy comprising, in weight
percent: about 0.09 percent aluminum, cobalt is present, about 20.9
percent chromium, about 7.91 percent iron, about 7.92 percent
molybdenum, about 3.48 percent niobium, about 1.57 percent
titanium, tantalum is present and is present in a concentration of
up to 3 percent and the balance nickel; wherein the nickel-base
superalloy comprising the engine component has a crack propagation
resistance of at least about 2139 hours to failure at 1100.degree.
F. in the presence of steam and a yield strength of at least about
130 ksi at a temperature of 750.degree. F.; and wherein the
nickel-base superalloy comprising the engine component has a grain
size of less than about 28 microns..Iaddend.
.Iadd.71. The turbine engine component of claim 70 wherein the
.gamma.'' tetragonal phase providing the crack propagation
resistance at 1100.degree. F., and grain size is achieved by first
homogenizing the nickel-base superalloy, then shaping the
superalloy at a temperature below the homogenization temperature,
then solutioning the shaped superalloy at a temperature below a
.delta.-solvus temperature or Laves solvus temperature of the
shaped superalloy to partially solution the shaped superalloy to
precipitate in a matrix the phase that is primarily .gamma.''
tetragonal..Iaddend.
.Iadd.72. A turbine disc for a gas turbine engine comprising: a
nickel-base superalloy including a .gamma.'' tetragonal phase and
having a composition, in weight percent, of between about 0.05 and
about 0.5 percent aluminum, cobalt is present and is present in a
concentration up to about 5 percent, between about 19 and 22
percent chromium, up to about 8 percent iron, between about 6 and
about 9 percent molybdenum, between about 3.3 and about 5.4 percent
niobium, tantalum is present and is present in a concentration of
up to 3 percent, between about 0.2 and about 1.6 percent titanium
and the balance nickel; wherein the nickel-base superalloy
comprising the turbine engine component has a crack propagation
resistance of at least about 200 hours to failure at 1100.degree.
F. in the presence of steam and a yield strength of at least about
130 ksi at a temperature of 750.degree. F.; and wherein the
.gamma.'' tetragonal phase providing the crack propagation
resistance at 1100.degree. F. is achieved by first homogenizing the
nickel-base superalloy, then shaping the superalloy at a
temperature below the homogenization temperature, then solutioning
the shaped superalloy at a temperature below a .delta.-solvus
temperature or Laves solvus temperature of the shaped superalloy to
partially solution the shaped superalloy to precipitate in a matrix
the phase that is primarily .gamma.'' tetragonal..Iaddend.
.Iadd.73. The turbine disc of claim 72 wherein the nickel-base
superalloy comprises about 0.5 percent aluminum, about 21.5 percent
chromium, about 2.5 percent iron, about 9 percent molybdenum, about
5.1 percent niobium about 0.9 percent titanium and the balance
nickel; wherein the nickel-base superalloy has a crack propagation
resistance of at least about 1680 hours to failure at 1100.degree.
F. in the presence of steam; and wherein the nickel-base superalloy
further has a yield strength of at least about 160 ksi at a
temperature of 750.degree. F., a room temperature yield strength of
at least about 177 ksi and a room temperature ultimate tensile
strength of at least about 221 ksi..Iaddend.
.Iadd.74. The turbine disc of claim 72 wherein the nickel-base
superalloy comprises about 0.5 percent aluminum, about 21.5 percent
chromium, about 2.5 percent iron, about 9 percent molybdenum, about
5.1 percent niobium about 0.9 percent titanium and the balance
nickel; wherein the nickel-base superalloy has a crack propagation
resistance of at least about 1680 hours to failure at 1100.degree.
F. in the presence of steam; and wherein the nickel-base superalloy
further has a grain size of less than about 5 microns..Iaddend.
.Iadd.75. A turbine disc for a gas turbine engine comprising: a
nickel-base superalloy including a .gamma.'' tetragonal phase and
having a composition, in weight percent, about 0.5 percent
aluminum, cobalt is present, about 19 percent chromium, about 18.5
percent iron, about 3 percent molybdenum, about 5.1 percent
niobium, about 0.9 percent titanium, tantalum is present and is
present in a concentration of up to 3 percent and the balance
nickel; wherein the nickel-base superalloy comprising the turbine
disc has a crack propagation resistance of at least about 200 hours
to failure at 1100.degree. F. in the presence of steam; wherein the
nickel-base superalloy comprising the turbine disc has a yield
strength of at least about 146 ksi at a temperature of 750.degree.
F., a room temperature yield strength of at least about 164 ksi and
a room temperature ultimate tensile strength of at least about 212
ksi; and wherein the .gamma.'' tetragonal phase providing the crack
propagation resistance at 1100.degree. F., the yield strength at
750.degree., the room temperature yield strength and the room
temperature ultimate tensile strength is achieved by first
homogenizing the nickel-base superalloy, then shaping the
superalloy at a temperature below the homogenization temperature,
then solutioning the shaped superalloy at a temperature below a
.delta.-solvus temperature or Laves solvus temperature of the
shaped superalloy to partially solution the shaped superalloy to
precipitate in a matrix the phase that is primarily .gamma.''
tetragonal..Iaddend.
.Iadd.76. A turbine disc for a gas turbine engine comprising: a
nickel-base superalloy including a .gamma.'' tetragonal phase and
having a composition, in weight percent, about 0.5 percent
aluminum, cobalt is present, about 19 percent chromium, about 18.5
percent iron, about 3 percent molybdenum, about 5.1 percent
niobium, about 0.9 percent titanium, tantalum is present and is
present in a concentration of up to 3 percent and the balance
nickel; wherein the nickel-base superalloy comprising the turbine
disc has a crack propagation resistance of at least about 200 hours
to failure at 1100.degree. F. in the presence of steam and a yield
strength of at least about 130 ksi at a temperature of 750.degree.
F.; wherein the nickel-base superalloy comprising the turbine disc
has a grain size of less than about 5 microns; and wherein the
.gamma.'' tetragonal phase providing the crack propagation
resistance at 1100.degree. F., the yield strength at 750.degree.,
the room temperature yield strength and the room temperature
ultimate tensile strength is achieved by first homogenizing the
nickel-base superalloy, then shaping the superalloy at a
temperature below the homogenization temperature, then solutioning
the shaped superalloy at a temperature below a .delta.-solvus
temperature or Laves solvus temperature of the shaped superalloy to
partially solution the shaped superalloy to precipitate in a matrix
the phase that is primarily .gamma.'' tetragonal..Iaddend.
.Iadd.77. A turbine disc for a gas turbine engine comprising: a
nickel-base superalloy including a .gamma.'' tetragonal phase and
having a composition, in weight percent, of about 0.09 percent
aluminum, cobalt is present, about 20.9 percent chromium, about
7.91 percent iron, about 7.92 percent molybdenum, about 3.48
percent niobium, about 1.57 percent titanium, tantalum is present
and is present in a concentration of up to 3 percent and the
balance nickel; wherein the nickel-base superalloy comprising the
turbine disc has a crack propagation resistance of at least about
2139 hours to failure at 1100.degree. F. in the presence of steam;
wherein the nickel-base superalloy comprising the turbine disc has
a yield strength of at least about 163 ksi at a temperature of
750.degree. F., a room temperature yield strength of at least about
177 ksi and a room temperature ultimate tensile strength of about
220 ksi; and wherein the .gamma.'' tetragonal phase providing the
crack propagation resistance at 1100.degree. F., the yield strength
at 750.degree., the room temperature yield strength and the room
temperature ultimate tensile strength is achieved by first
homogenizing the nickel-base superalloy, then shaping the
superalloy at a temperature below the homogenization temperature,
then solutioning the shaped superalloy at a temperature below a
.delta.-solvus temperature or Laves solvus temperature of the
shaped superalloy to partially solution the shaped superalloy to
precipitate in a matrix the phase that is primarily .gamma.''
tetragonal..Iaddend.
.Iadd.78. A turbine disc for a gas turbine engine comprising: a
nickel-base superalloy including a .gamma.'' tetragonal phase and
having a composition, in weight percent, of about 0.09 percent
aluminum, cobalt is present, about 20.9 percent chromium, about
7.91 percent iron, about 7.92 percent molybdenum, about 3.48
percent niobium, about 1.57 percent titanium, tantalum is present
and is present in a concentration of up to 3 percent and the
balance nickel; wherein the nickel-base superalloy comprising the
turbine disc has a crack propagation resistance of at least about
2139 hours to failure at 1100.degree. F. in the presence of steam
and a yield strength of at least about 130 ksi at a temperature of
750.degree. F.; wherein the nickel-base superalloy comprising the
turbine disc has a grain size of less than about 28 microns; and
wherein the .gamma.'' tetragonal phase providing the crack
propagation resistance at 1100.degree. F., the yield strength at
750.degree., the room temperature yield strength and the room
temperature ultimate tensile strength is achieved by first
homogenizing the nickel-base superalloy, then shaping the
superalloy at a temperature below the homogenization temperature,
then solutioning the shaped superalloy at a temperature below a
.delta.-solvus temperature or Laves solvus temperature of the
shaped superalloy to partially solution the shaped superalloy to
precipitate in a matrix the phase that is primarily .gamma.''
tetragonal..Iaddend.
.Iadd.79. A turbine engine component formed from a nickel-base
superalloy, the nickel-base superalloy including a .gamma.''
tetragonal phase, the nickel-base superalloy comprising, in weight
percent: between about 0.1 and about 0.6 percent aluminum, cobalt
is present and is present in a concentration up to about 5 percent,
between about 19 and 22 percent chromium, up to about 8 percent
iron, between about 6 and about 9 percent molybdenum, between about
3.5 and about 5.1 percent niobium, tantalum is present and is
present in a concentration of up to 3 percent, between about 0.6
and about 2.0 percent titanium and the balance nickel; wherein the
nickel-base alloy comprising the turbine engine component has a
crack propagation resistance of at least about 200 hours to failure
at 1100.degree. F. in the presence of steam and a yield strength of
at least about 130 ksi at a temperature of 750.degree. F.; and
wherein the .gamma.'' tetragonal phase providing the crack
propagation resistance at 1100.degree. F. is achieved by first
homogenizing the nickel-base superalloy, then shaping the
superalloy at a temperature below the homogenization temperature,
then solutioning the shaped superalloy at a temperature below a
.delta.-solvus temperature or Laves solvus temperature of the
shaped superalloy to partially solution the shaped superalloy to
precipitate in a matrix the phase that is primarily .gamma.''
tetragonal..Iaddend.
.Iadd.80. A turbine engine component formed from a nickel-base
superalloy, the nickel-base superalloy containing a .gamma.''
tetragonal phase, the nickel-base superalloy comprising, in weight
percent: between about 0.2 and about 0.6 percent aluminum, cobalt
is present and is present in a concentration up to about 5 percent,
between about 19 and 22 percent chromium, up to about 8 percent
iron, between about 6 and about 9 percent molybdenum, between about
3.6 and about 5.5 percent niobium, tantalum is present and is
present in a concentration of up to 3 percent, between about 0.6
and about 2.0 percent titanium and the balance nickel; wherein the
nickel-base superalloy comprising the turbine engine component has
a crack propagation resistance of at least about 200 hours to
failure at 1100.degree. F. in the presence of steam and a yield
strength of at least about 130 ksi at a temperature of 750.degree.
F.; and wherein the .gamma.'' tetragonal phase providing the crack
propagation resistance at 1100.degree. F. is achieved by first
homogenizing the nickel-base superalloy, then shaping the
superalloy at a temperature below the homogenization temperature,
then solutioning the shaped superalloy at a temperature below a
.delta.-solvus temperature or Laves solvus temperature of the
shaped superalloy to partially solution the shaped superalloy to in
a matrix the phase that is primarily .gamma.''
tetragonal..Iaddend.
.Iadd.81. The turbine engine component of claim 80 wherein the
nickel-base superalloy includes about 21.5 percent chromium, about
2.5 percent iron and about 9 percent molybdenum..Iaddend.
.Iadd.82. A turbine disc for a gas turbine engine comprising: a
nickel-base superalloy including a .gamma.'' tetragonal phase and
having a composition, in weight percent, of between about 0.2 and
about 0.6 percent aluminum, cobalt is present and is present in a
concentration up to about 5 percent, between about 19 and 22
percent chromium, up to about 8 percent iron, between about 6 and
about 9 percent molybdenum, between about 3.6 and about 5.5 percent
niobium, tantalum is present and is present in a concentration of
up to 3 percent, between about 0.6 and about 2.0 percent titanium
and the balance nickel; wherein the nickel-base superalloy
comprising the turbine disc has a crack propagation resistance of
at least about 200 hours to failure at 1100.degree. F. in the
presence of steam and a yield strength of at least about 130 ksi at
a temperature of 750.degree. F.; and wherein the .gamma.''
tetragonal phase providing the crack propagation resistance at
1100.degree. F. is achieved by first homogenizing the nickel-base
superalloy, then shaping the superalloy at a temperature below the
homogenization temperature, then solutioning the shaped superalloy
at a temperature below a .delta.-solvus temperature or Laves solvus
temperature of the shaped superalloy to partially solution the
shaped superalloy to precipitate in a matrix the phase that is
primarily .gamma.'' tetragonal..Iaddend.
.Iadd.83. The turbine disc of claim 82 wherein the nickel-base
superalloy includes about 21.5 percent chromium, about 2.5 percent
iron and about 9 percent molybdenum..Iaddend.
Description
BACKGROUND OF THE INVENTION
The invention relates to articles, such as, but not limited to,
turbine engine components, that have high yield strength and
time-dependent crack propagation resistance. More particularly, the
invention relates to articles that have high yield strength and
time-dependent crack propagation resistance and are formed from
nickel-based superalloys. Even more particularly, the invention
relates to nickel-based superalloys that are used to form articles,
such as turbine engine components, that exhibit both high yield
strength and time-dependent crack propagation resistance.
During operation of jet and land-based turbine engines, high
temperatures and stresses are normally encountered. In order to
function properly over extended periods of time, the components
within these turbine engines must retain high strength and other
properties at temperatures in excess of 850.degree. F. Nickel-base
superalloys have long been recognized as having properties at
elevated temperatures that are superior to those of steel-based
components, such as turbine wheels, and which meet the performance
requirements of turbines. Precipitates of a .gamma.'' ("gamma
double prime") phase are believed to contribute to superior
performance of many of these nickel-base superalloys at high
temperatures. Consequently, nickel-base superalloys such as Alloy
706 have been widely used to form components in turbines that are
used for land-based power generation.
Newer turbine engine designs have imposed even more demanding
requirements upon the properties of materials that are used to form
components. In addition to higher operating temperatures and
stresses than those encountered in previous designs, the newer
turbine engines can present a different operating environment that
is potentially more aggressive than that of earlier turbines. One
example of a more aggressive operating environment is the use of
steam to cool hot gas path materials in the current generation of
power turbine engines. Thus, materials having improved properties
are needed to deliver a performance level that was not contemplated
in the previous generation of turbine engines.
Turbine engine components, as well as other articles, formed from
nickel-base superalloys can be subjected to time-dependent
propagation of cracks that are either incipient or formed during
fabrication or use of the component. Time-dependent crack
propagation depends on both the frequency of stress application and
the time spent under stress, or "hold-time." A discussion of the
dependence of crack propagation upon frequency and hold time can be
found in U.S. Pat. No. 5,129,969 issued Jul. 14, 1992, to M. Henry
and assigned to the same assignee as the present application.
Because such cracks tend to grow while the component is under the
stress of turbine engine operation and can lead to catastrophic
failure of the component as well as the entire turbine engine, it
is desirable that a component possess a certain level of
time-dependent crack propagation resistance (TDCPR) at its service
temperature. The TDCPR of an alloy or an article formed from the
alloy can be expressed in hours to failure at a given temperature
and fracture mechanics driving force.
During operation, gas turbine discs are subjected to large radial
temperature gradients. In particular, land-based gas turbine
engines operate with long hold times at high temperature. For these
applications, strength properties can dominate and drive the bore
design, whereas resistance to time-dependent crack growth can
dominate the rim design. Turbine wheels or discs must therefore
possess adequate time-dependent crack propagation resistance in the
rim regions of the wheel at one temperature and adequate tensile
strength at a second, lower temperature in the area surrounding the
bore of the wheel. It is therefore desirable that the turbine
wheels be formed from a material that provides the necessary
combination of TDCPR and strength at high temperatures.
The nickel-base superalloys that are either being used in current
turbines or are being considered for use in proposed turbine engine
designs do not possess the necessary combination of crack
propagation resistance and strength. Alloy 718, for example, has
been chosen as a turbine wheel material due to its acceptable TDCPR
in the steam environment of current turbine designs, but its TDCPR
could be inadequate in more advanced designs. Alloy 625 has
excellent crack propagation resistance, but has insufficient
strength for turbine wheel applications. Commercially available
alloys such as ASTROLOY.TM. have good combinations of TDCPR and
strength when the material is processed to form articles that are
sized small enough to be cooled quickly--i.e., at rates between
about 150.degree. F. and about 600.degree. F. per minute--from the
solutioning temperature. When processed on the scale of modern
land-based gas turbine wheels, however, such alloys have inadequate
strength. This is due in part to the fact that the alloy that is
obtained is a .gamma.' ("gamma prime") strengthened alloy rather
than a .gamma.'' ("gamma double prime") strengthened alloy. The
.gamma.' strengthened alloy exhibits accelerated precipitation
kinetics.
As their operational parameters are extended, both land-based and
jet turbine engines will need to incorporate components that are
formed from materials that possess the time dependent crack
propagation resistance and strength required for these
applications. Therefore, what is needed is an article, such as a
turbine engine component, that possesses adequate time dependent
crack propagation resistance at high temperatures. What is also
needed is an article that possesses a combination of time dependent
crack propagation resistance and strength at high temperatures.
What is further needed is a nickel-base superalloy that can be
formed into an article, such as a turbine engine component, having
the necessary combination of TDCPR and strength at high
temperatures.
BRIEF SUMMARY OF THE INVENTION
The present invention satisfies these needs and others by providing
an article, such as, but not limited to, turbine engine components
formed from a nickel-base superalloy. The article formed from the
nickel-base superalloy has the time dependent crack propagation
resistance (TDCPR) and strength that meet the performance
requirements of high strength, high temperature systems, such as a
turbine engine. Methods of making the superalloy and the article
from the superalloy having these properties are also disclosed.
Accordingly, one aspect of the present invention is to provide an
article formed from a nickel-base superalloy, the nickel-base
superalloy containing a .gamma.'' tetragonal phase and comprising
aluminum, titanium, tantalum, niobium, chromium, molybdenum, and
the balance nickel, wherein the article has a time dependent crack
propagation resistance of at least about 20 hours to failure at
about 1100.degree. F. in the presence of steam under the screening
conditions used in this study.
A second aspect of the present invention is to provide a
nickel-base superalloy for forming an article. The nickel-base
superalloy contains a .gamma.'' tetragonal phase and comprises
aluminum, titanium, tantalum, niobium, chromium, molybdenum, at
least one element selected from the group consisting of iron and
cobalt, and the balance nickel, wherein the nickel-base superalloy
turbine component has a crack propagation resistance of at least 20
hours to failure at about 1100.degree. F. in the presence of steam
and a yield strength of greater than 130 ksi at about 750.degree.
F.
A third aspect of the present invention is to provide an article
formed from a nickel-base superalloy, the nickel-base superalloy
containing a .gamma.'' tetragonal phase and comprising aluminum,
titanium, tantalum, niobium, chromium, molybdenum, at least one
element selected from the group consisting of iron and cobalt, and
the balance nickel, wherein the article has a crack propagation
resistance of at least 20 hours to failure at about 1100.degree. F.
in the presence of steam and a yield strength of greater than 130
ksi at about 750.degree. F.
A fourth aspect of the present invention is to provide a method of
making a nickel-base superalloy billet containing a .gamma.''
tetragonal phase and having a crack propagation resistance of at
least 20 hours to failure at about 1100.degree. F. in the presence
of steam and a yield strength of greater than 130 ksi at about
750.degree. F. The method comprises the steps of: forming an ingot
of the nickel-base superalloy; remelting the ingot a first time;
remelting the ingot a second time; homogenizing the ingot; and
billetizing the ingot, thereby creating the nickel-base superalloy
billet.
A fifth aspect of the present invention is to provide a method of
making a nickel-base superalloy article containing a .gamma.''
tetragonal phase and having a crack propagation resistance of at
least 20 hours to failure at 1100.degree. F. in the presence of
steam and a yield strength of greater than 130 ksi at about
750.degree. F. The method comprises the steps of: forming an ingot
of the nickel-base superalloy; remelting the ingot a first time;
remelting the ingot a second time; homogenizing the ingot;
billetizing the ingot, thereby creating a billet; and hot-working
the billet to form the article.
These and other aspects, advantages, and salient features of the
invention will become apparent from the following detailed
description, the accompanying drawings, and the appended
claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram of a turbine engine;
FIG. 2 is a schematic diagram representing the time dependent crack
propagation resistance (TDCPR) screening test; and
FIG. 3 is a plot of crack propagation resistance, measured for
partially solutioned and fully solutioned alloys at 1100.degree. F.
in the presence of steam, for a nickel-base superalloy of the
present invention and prior-art nickel-base superalloys.
DETAILED DESCRIPTION OF THE INVENTION
In the following description, like reference characters designate
like or corresponding parts throughout the several views shown in
the figures. It is also understood that terms such as "top,"
"bottom," "outward," "inward," and the like are words of
convenience and are not to be construed as limiting terms.
Referring to the drawings in general and to FIG. 1 in particular,
it will be understood that the illustrations are for the purpose of
describing a preferred embodiment of the invention and are not
intended to limit the invention thereto. It is understood that
articles other than turbine components, for which the combination
of strength and resistance to high temperature time-dependent crack
growth are desired, are considered to be within the scope of the
present invention. Such articles include, but are not limited to,
tooling, valves, and down-hole equipment used in oil field
operations. FIG. 1 is a schematic diagram of a turbine engine 10
that includes at least one turbine engine component 11 of the
present invention. The turbine engine 10 may either be a land-based
turbine, such as those widely used for power generation, or an
aircraft engine. Air enters the inlet 12 of the turbine engine 10
and is first compressed in the compressor 14. The high pressure air
then enters the combustor 16 where it is combined with a fuel, such
as natural gas or jet fuel, and burned continuously at a constant
pressure. The hot, high pressure air exiting the combustor 16 is
then expanded through a turbine 18, where energy is extracted to
power the compressor, before exiting the turbine engine 10 through
a discharge outlet 20.
The turbine engine 10 comprises a number of turbine components 11
of the present invention that are subject to high temperatures
and/or stresses during operation. These turbine components 11
include, but are not limited to: rotors 22 and stators 24 in the
compressor 14; combustor cans 26 and nozzles 28 in the combustor
16; discs, wheels and buckets 30 in the turbine 18; and the like.
In the present invention, the turbine components 11 are formed from
nickel-base superalloys having compositions in the ranges described
herein and a crack propagation resistance (TDCPR) of at least 20
hours to failure at 1100.degree. F. in the presence of steam under
the conditions described herein, which is the TDCPR of Alloy 718.
Preferably, the turbine components 11 have a crack propagation
resistance of at least 200 hours to failure at 1100.degree. F. in
the presence of steam. Most preferably, the turbine engine 10
includes turbine components 11 having a TDCPR of at least 1000
hours to failure at 1100.degree. F. in the presence of steam.
FIG. 2 is a schematic representation of a static crack growth test
for determining the crack propagation resistance of a material or
an article formed from the material. A fatigue pre-crack 32 is
created in a test article 30 formed from the material and the test
article 30 is heated to the test or service temperature in the
presence of steam. A steam environment is used in the static growth
tests because steam is generally considered to be a more hostile
environment than air for intergranular cracking in nickel-base
superalloys. The performance of the alloys of the present invention
in air is found to be superior to their performance in the presence
of steam. Thus, test results obtained in the presence of steam for
the alloys represent a lower performance limit of the alloys. A
stress intensity factor 36 of 26 ksi/in.sup.2 is applied to the
fatigue pre-crack 32. The growth rate of the fatigue pre-crack 32
is monitored until the test article 30 fails, or until a
preselected time is reached, in which case the time dependent
portion of the crack advance is measured. Depending on whether the
test article 30 fails or the preselected time is reached, either
the time to failure or the degree of crack advance can be
correlated with static crack growth rates.
The article of the present invention, which may be a turbine
component 11 of the turbine engine 10, is formed from a nickel-base
superalloy. To form an article having a crack propagation
resistance that is at least equal to that of Alloy 718, the
nickel-base superalloy used to form the article has a .gamma.''
tetragonal phase and comprises aluminum, titanium, tantalum,
niobium, chromium, molybdenum, and the balance nickel. The
nickel-base superalloy may further include cobalt and iron and
comprises: between about 0.05 and about 2.0 weight percent
aluminum; up to about 10 weight percent cobalt; between about 15
and about 25 weight percent chromium; up to about 40 weight percent
iron; up to about 12 weight percent molybdenum; between about 2 and
about 7 weight percent niobium; up to about 6 weight percent
tantalum; up to about 2.5 weight percent titanium; and a balance of
nickel.
Preferably, the article of the present invention has a crack
propagation resistance of at least 200 hours to failure at
1100.degree. F. in the presence of steam under the test conditions
described herein. As embodied in the present invention, articles
having this level of TDCPR are formed from a nickel-base superalloy
comprising: between about 0.05 and about 0.5 weight percent
aluminum; up to about 5 weight percent cobalt; between about 19 and
about 22 weight percent chromium; up to about 8.0 weight percent
iron; between about 6 and about 9 weight percent molybdenum;
between about 3.3 and about 5.4 weight percent niobium; up to about
3 weight percent tantalum; between about 0.2 and about 1.6 weight
percent titanium; and a balance of nickel.
In another embodiment of the present invention, the nickel-base
superalloy comprises: between about 0.1 and about 0.6 weight
percent aluminum; up to about 5 weight percent cobalt; between
about 19 and about 22 weight percent chromium; up to about 8.0
weight percent iron; between about 6 and about 9 weight percent
molybdenum; between at least 3.5 and about 5.1 weight percent
niobium; up to about 3 weight percent tantalum; between about 0.6
and about 2.0 weight percent titanium; and a balance of nickel.
More preferably, the nickel-base superalloy comprises: between
about 0.2 and about 0.6 weight percent aluminum; up to about 5
weight percent cobalt; between about 19 and about 22 weight percent
chromium; up to about 8.0 weight percent iron; between about 6 and
about 9 weight percent molybdenum; between at least 3.6 and about
5.5 weight percent niobium; up to about 3 weight percent tantalum;
between about 0.6 and about 2.0 weight percent titanium; and a
balance of nickel. Even more preferably, the nickel-base superalloy
comprises: between about 0.2 and about 0.6 weight percent aluminum;
about 21.5 weight percent chromium; about 2.5 weight percent iron;
about 9 weight percent molybdenum; between at least 3.6 and about
5.5 weight percent niobium; up to about 3 weight percent tantalum;
between about 0.6 and about 2.0 weight percent titanium; and a
balance of nickel. Alternatively, the nickel-base superalloy
preferably comprises: between about 0.1 and about 0.5 weight
percent aluminum; between about 1.5 and about 5 weight percent
cobalt; between about 19 and about 21 weight percent chromium;
about 8.0 weight percent iron; between about 6 and about 9 weight
percent molybdenum; at least 3.5 weight percent niobium; between
about 2 and about 3 weight percent tantalum; between about 0.8 and
about 1.0 weight percent titanium; and a balance of nickel.
Most preferably, the article of the present invention has a TDCPR
of at least 1000 hours to failure at 1100.degree. F. in the
presence of steam. Alloy ARC017A, comprising about 0.5 weight
percent aluminum, about 21.5 weight percent chromium, about 2.5
weight percent iron, about 9 weight percent molybdenum, about 5.1
weight percent niobium, about 0.9 weight percent titanium, and a
balance of nickel; and alloy ARC054, comprising about 0.5 weight
percent aluminum, about 5 weight percent cobalt, about 19 weight
percent chromium, about 8 weight percent iron, about 0.4 weight
percent molybdenum, about 3.5 weight percent niobium, about 3
weight percent tantalum, about 1.0 weight percent titanium, and a
balance of nickel, are representative of nickel-base superalloys
that can be used to form articles, including turbine components 11,
having this level of time dependent crack propagation
resistance.
As previously mentioned, turbine wheels or discs must possess
adequate time dependent crack propagation resistance in the rim
regions of the wheel at one temperature and adequate tensile
strength at a second, lower temperature in the area surrounding the
bore of the wheel. Thus, one embodiment of the invention includes
an article, such as a turbine component 11, which, in addition to
having a time dependent crack propagation resistance of at least 20
hours to failure at 1100.degree. F. in the presence of steam, has a
yield strength of 149 ksi, and, preferably, 160 ksi, at 750.degree.
F., under the test conditions described herein.
An article, such as a turbine component 11, of the present
invention is formed from a nickel-base superalloy. The nickel-base
superalloy can preferably be made by what is commonly referred to
as a "triple melt" process, although it is readily understood by
those of ordinary skill in the art that alternate processing routes
may be used to obtain the microstructure of the nickel-base
superalloys of the present invention. In the triple melt process,
the constituent elements are first combined in the necessary
proportions and melted, using a method such as vacuum induction
melting or the like, to form a molten alloy. The molten alloy is
then resolidified to form an ingot of the nickel-base superalloy.
The ingot is then re-melted using a process such as electro-slag
re-melting (ESR) or the like. A second re-melting is then performed
using a vacuum arc re-melting (VAR) process.
Following the second re-melt, the ingot is homogenized by a heat
treatment. The homogenizing heat treatment of the present invention
is preferably performed at a temperature that is as close to the
melting point of the material, while not encountering incipient
melting, as is practical. The ingot is then subjected to a
conversion process, in which the ingot is billetized, i.e.,
prepared and shaped for forging. The conversion process is carried
out at temperatures below that used during the homogenization
treatment and typically includes a combination of upset, heat
treatment, and drawing steps in which additional homogenization
occurs and the grain size in the ingot is reduced. The resulting
billet is then hot-worked using conventional means, such as
forging, to form the article. In order to control grain size, the
forged article is then subjected to at least one solutioning step
in which the article is heat treated at a temperatures below the
solvus temperature of the highest temperature phase of the material
to produce a partially solutioned nickel-base superalloy.
Preferably, the solution step is carried out at a temperature below
the .delta.-solvus or Laves solvus temperature of the nickel-base
superalloy. In contrast, prior-art final forging heat treatments
are often carried out above the .delta.-solvus temperature to
produce a fully solutioned nickel-base superalloy. During the
development of the alloys of the present invention, both partially
solutioned (i.e., the final post-forging heat treatment was carried
out below the .delta.-solvus temperature) and fully solutioned
(i.e., the final post-forging heat treatment was carried out above
the .delta.-solvus temperature) material test coupons were
evaluated.
A list of compositions prepared according to the present invention
is given in Table 1. In addition, the composition of several
commercial alloys, such as Alloy 718, Alloy 625, and Alloy 725, are
provided for comparison. Partially solutioned samples of Alloy 718,
Alloy 625, and Alloy 725 were treated according to the method
described herein. Table 2 lists the yield strengths at room
temperature, 750.degree. F., and 1100.degree. F. and the static
crack growth time-to-failure at 1100.degree. F. in both air and
steam for partially solutioned, heat treated alloys having the
compositions listed in Table 1. The results listed for Alloy 625,
and Alloy 725 are those obtained for samples treated according to
the present invention. Yield strengths at 750.degree. F. of the
nickel-base superalloys of the present invention ranged from about
130 to about 160 ksi. The nickel-base superalloys of the present
invention exhibited times-to-failure ranging from about 208 hours
to at least about 3360 hours in a steam atmosphere. These
time-to-failure values are superior to that measured for Alloy 718,
which had a yield strength of 146 ksi at 750.degree. F. and a
time-to-failure of about 20 hours. The superalloys prepared
according to the present invention also exhibited yield strengths
at 750.degree. F. that are comparable to or greater than that of
Alloy 718. This effect is contrary to the general trend observed in
prior-art nickel-base superalloys, in which any increase in time
dependent crack growth is most often associated with a
corresponding decrease in strength. In contrast to the alloys of
the present invention, Alloy 625, while having a crack growth
time-to-failure of about 1680 hours at 1100.degree. F. in the
presence of steam, lacks sufficient strength (94 ksi at 750.degree.
F.) for turbine applications such as wheels and discs. When treated
according to the method of the present invention, Alloy 725
exhibited a time-to-failure of about 2140 hours. Table 3 lists the
properties of fully solutioned nickel-base superalloys of the
present invention as well as Alloy 718, Alloy 625, and Alloy 725.
With the exception of alloys ARC067B and ARC076, the
times-to-failure in steam exhibited by the fully solutioned alloys
of the present invention and Alloys 718, 625, and 725, were less
than the times-to-failure in steam of the corresponding partially
solutioned alloys. The results indicate that the partial solution
heat treatment of the present invention increases the
time-to-failure of both the nickel-base superalloys of the present
invention and the prior-art nickel-base superalloys.
The time dependent crack propagation resistances, measured for
partially solutioned and fully solutioned alloys at 1100.degree. F.
in the presence of steam, of the nickel-base superalloys ARC054 and
ARC017A of the present invention and the commercially available
Alloy 718, Alloy 725, and Alloy 625 are compared in FIG. 3. In both
fully solutioned and partially solutioned conditions, the
nickel-base superalloys ARC054 and ARC017A of the present invention
have greater crack growth times-to-failure than that of Alloy 718.
Although Alloy 625 has a greater crack growth time-to-failure than
ARC054, the prior-art alloy possesses insufficient strength for
turbine applications such as wheels and discs. The values plotted
in FIG. 3 also serve to illustrate that the partial solution heat
treatment of the present invention increases the time-to-failure of
both the nickel-base superalloys of the present invention and the
prior-art nickel-base superalloys.
The nickel-base superalloys of the present invention collectively
represent a unique combination of strength and ductility at both
room temperature and high temperature and resistance to high
temperature time-dependent crack growth. In addition, the
nickel-base superalloys of the present invention are structurally
stable and can be cast and forged into very large components while
retaining grain sizes that provide good continuous low cycle
fatigue resistance. Specifically, the alloys ARC017A, ARC054, and
Alloy 725 have been scaled up using the previously described
"triple melt" process to yield a vacuum arc re-melt (VAR) ingot
having a diameter of about 20 inches. Each of the re-melted ingots
having diameters of about 20 inches was converted to a billet
having a diameter of about 10 inches.
TABLE-US-00001 TABLE 1 Compositions in Weight Percents Al Co Cr Fe
Mo Nb Ni Th Ti Alloy (w/o) (w/o) (w/o) (w/o) (w/o) (w/o) (w/o)
(w/o) (w/o) ARC009 0.25 0.0 20.0 37.5 0.00 2.90 37.6 0.0 1.75
ARC017A 0.50 0.0 21.5 2.50 9.00 5.10 60.3 0.0 0.90 ARC025 0.25 0.0
20.0 37.5 6.00 2.90 31.4 0.0 1.75 ARC031 0.20 0.0 21.5 2.50 9.00
5.50 60.9 0.0 0.20 ARC053 0.63 0.0 21.5 2.50 9.00 3.60 59.0 3.0
0.63 ARC054 0.45 5.0 19.0 8.00 6.35 3.50 53.5 3.0 1.00 ARC056 1.25
0.0 18.0 2.50 9.00 4.50 64.1 0.0 0.50 ARC067B 0.25 0.0 20.0 18.5
9.00 2.90 47.4 0.0 1.75 ARC076 0.09 1.5 21.0 8.00 9.00 3.50 54.0
2.0 0.80 Alloy 625 0.20 0.0 21.5 2.50 9.00 3.60 62.8 0.0 0.20 Alloy
718 0.50 0.0 19.0 18.5 3.00 5.10 52.8 0.0 0.90 Alloy 725 0.09 0.0
20.9 7.91 7.92 3.48 58.0 0.0 1.57
TABLE-US-00002 TABLE 2 Properties for Partially Solutioned Heat
Treated Materials 1100.degree. F. 1100.degree. F. 750.degree. F.
1100.degree. F. Air Static Steam Static Grain R.T. R.T. 750.degree.
F. 750.degree. F. Elong. 1100.degree. F. Elong. Crack Growth Crack
Growth Size Y.S. UTS R.T. Elong. Y.S. UTS to Fail 1100.degree. F.
UTS to Fail Time to Time to Alloy (microns) (ksi) (ksi) to Fail (%)
(ksi) (ksi) (%) Y.S. (ksi) (ksi) (%) fail (h) fail (h) ARC009 14
148 174 10 136 157 10 126 146 13 3360 ARC017A 5 177 221 12 160 210
17 155 207 21 1680 ARC025 12 147 186 9 143 171 8 138 165 10 1120
ARC031 12 147 192 28 132 174 27 129 180 36 1680 1680 ARC053 48/8*
149 191 11 146 190 19 142 193 24 97 236 ARC054 10 150 206 26 140
192 23 135 189 29 2139 1680 ARC056 34/10* 144 198 26 133 184 28 131
192 24 244 208 ARC067B 6 139 194 13 141 188 15 139 187 19 323
ARC076 158 202 26 143 180 23 230 Alloy 625 10 113 170 43 94 147 40
95 151 39 840 1680 Alloy 718 5 164 212 27 146 184 22 142 176 28 20
Alloy 725 28/5* 177 220 14 163 202 16 157 200 21 2139 *Bimodal
particle size distribution observed
TABLE-US-00003 TABLE 3 Properties for Fully Solutioned Heat Treated
Materials 1100.degree. F. 1100.degree. F. 750.degree. F.
1100.degree. F. Air Static Steam Static Grain R.T. R.T. 750.degree.
F. 750.degree. F. Elong. 1100.degree. F. Elong. Crack Growth Crack
Growth Size Y.S. UTS R.T. Elong. Y.S. UTS to Fail 1100.degree. F.
UTS to Fail Time to Time to Alloy (microns) (ksi) (ksi) to Fail (%)
(ksi) (ksi) (%) Y.S. (ksi) (ksi) (%) fail (h) fail (h) ARC009 40
146 184 22 131 163 17 125 154 22 18 ARC017A 40 155 212 28 141 189
25 141 194 21 183 ARC025 50 131 165 10 120 152 14 119 149 13 248
ARC031 50 146 189 37 129 162 33 127 167 33 76 56 ARC053 60 127 181
28 101 149 31 109 165 29 1120 1680 ARC054 60 165 206 27 144 179 26
139 178 22 65 54 ARC056 60 121 184 38 109 165 36 108 165 26 312 234
ARC067B 90 108 162 20 100 146 31 100 144 27 3360 ARC076 80 142 187
29 123 161 29 118 160 29 324 Alloy 625 60 102 162 45 82 134 43 75
127 49 1680 Alloy 718 45 168 202 24 149 173 20 145 167 20 4 Alloy
725 56 149 209 25 136 181 25 133 173 19 74
While various embodiments are described herein, it will be
appreciated from the specification that various combinations of
elements, variations, or improvements therein may be made by those
skilled in the art, and are within the scope of the invention. For
example, the nickel-base superalloy of the present invention may be
used to form articles other than turbine components, for which the
combination of strength and resistance to high temperature
time-dependent crack growth are desired.
* * * * *