Claims
- 1. A work-strengthened alloy, which comprises
- (a) a gamma prime phase including gamma prime phase particles having a cross-sectional size of 10 nanometers or more; and
- (b) a hexagonal close packed phase; said alloy comprising the following elements in percent by weight:
- ______________________________________molybdenum 6-16chromium 13-25iron 0-23nickel 10-55carbon 0-0.05boron 0-0.05cobalt balance, at least 20,______________________________________
- said alloy also containing one or more elements which form gamma prime phase with nickel, the electron vacancy number, N.sub.v, of the allow being defined by
- N.sub.v =0.61 Ni+1.71 Co+2.66 Fe +4.66 Cr+5.66 Mo
- wherein the respective chemical symbols represent the effective atomic fractions of the respective elements present in the alloy, said number not exceeding the value
- N.sub.v =2.82-0.017 W.sub.Fe,
- where W.sub.Fe is the percent by weight of iron in the alloy for those alloys containing no iron or less than 13 percent by weight iron and W.sub.Fe is 13 for alloys containing 13-23 percent by weight iron.
- 2. An alloy as defined in claim 1, wherein the gamma prime phase is present in an amount of 5-60 percent by volume of the alloy.
- 3. An alloy as defined in claim 1, wherein the gamma prime phase is in the form of particles of size up to and including 1 micron.
- 4. An alloy as defined in claim 1, wherein the gamma prime phase is present in the form of particles, said particles comprising at least two different fractions, a first fraction being of particles sized up to and including 30 nanometers and a second fraction being of particles sized greater than 30 nanometers and up to and including 1 micron.
- 5. An alloy as defined in claim 1, said alloy having been worked at a temperature below the lower temperature limit of the hcp-fcc phase-transformation zone to achieve a reduction in cross-section of from 5 to 70%.
- 6. An alloy as defined in claim 5, said alloy having been aged at a temperature of from 550.degree.-800.degree. C. after working of the alloy.
- 7. An alloy as defined in claim 1, wherein the content of iron is greater than 6 percent by weight.
- 8. An alloy as defined in claim 1, wherein said one or more elements which form gamma prime phase with nickel are selected from the group consisting of aluminum, titanium, columbium, tantalum, vanadium, tungsten, zirconium and silicon.
- 9. An alloy as defined in claim 1, which comprises the following elements in percent by weight:
- ______________________________________cobalt 23-58molybdenum 6-12chromium 15-21iron 0-23aluminum 1-3titanium 0-5columbium 0-2nickel 18-55carbon 0-0.03boron 0-0.03______________________________________
- the electron vacancy number, N.sub.v, of the alloy being as defined in claim 1.
- 10. An alloy as defined in claim 1, which comprises the following elements in percent by weight:
- ______________________________________cobalt 23-58molybdenum 6-12chromium 18-22iron 7-10titanium 2-4aluminum 0.1-0.7columbium 0.1-1nickel 18-30carbon 0-0.03boron 0-0.03______________________________________
- the electron vacancy number, N.sub.v, being as defined in claim 1.
- 11. A work-strengthened alloy which, prior to strengthening by working, includes a gamma prime phase comprising gamma prime phase particles having a cross-sectional size of 10 nanometers or more, said alloy comprising the following elements in percent by weight:
- ______________________________________molybdenum 6-16chromium 13-25iron 0-23nickel 10-55carbon 0-0.05boron 0-0.05cobalt balance, at least 20,______________________________________
- said alloy also containing one or more elements which form gamma prime phase with nickel
- the electron vacancy number, N.sub.v, of the alloy being defined by
- N.sub.v =0.61 Ni+1.71 Co+2.66 Fe +4.66 Cr+5.66 Mo
- wherein the respective chemical symbols represent the effective atomic fractions of the respective elements present in the alloy, said number not exceeding the value
- N.sub.v =2.82-0.017 W.sub.Fe,
- where W.sub.Fe is the percent by weight of iron in the alloy for those alloys containing no iron or less than 13 percent by weight iron and W.sub.Fe is 13 for alloys containing 13-23 percent by weight iron.
- 12. An alloy as defined in claim 11, wherein the gamma prime phase is present in an amount of 5-60 percent by volume of the alloy.
- 13. An alloy as defined in claim 11, wherein the gamma prime phase is in the form of particles of size up to and including 1 micron.
- 14. An alloy as defined in claim 11, wherein the gamma prime phase is present in the form of particles, said particles comprising at least two different fractions, a first fraction being of particles sized up to and including 30 nanometers and a second fraction being of particles sized greater than 30 nanometers and up to and including 1 micron.
- 15. An alloy as defined in claim 11, wherein the gamma prime phase is initially formed by heating at a temperature of from 600.degree.-900.degree. C.
- 16. An alloy as defined in claim 11, wherein the content of iron is greater than 6 percent by weight.
- 17. An alloy as defined in claim 11, wherein said one or more elements forming gamma prime phase with nickel are selected from the group consisting of aluminum, titanium, columbium, tantalum, vanadium, tungsten, zirconium and silicon.
- 18. An alloy as defined in claim 11, which comprises the following elements in percent by weight:
- ______________________________________cobalt 23-58molybdenum 6-12chromium 15-21iron 0-23aluminum 1-3titanium 0-5columbium 0-2nickel 18-55carbon 0-0.03boron 0-0.03______________________________________
- the electron vacancy number, N.sub.v, of the alloy being as defined in claim 11.
- 19. An alloy as defined in claim 11, which comprises the following elements in percent by weight:
- ______________________________________cobalt 23-58molybdenum 6-12chromium 18-22iron 7-10titanium 2-4aluminum 0.1-0.7columbium 0.1-1nickel 18-30carbon 0-0.03boron 0-0.03,______________________________________
- the electron vacancy number, N.sub.v, being as defined in claim 11.
Parent Case Info
This application is a continuation of Ser. No. 358,959, filed May 30, 1989, which was a continuation of application Ser. No. 110,132 filed Oct. 19, 1987, now U.S. Pat. No. 4,908,069.
US Referenced Citations (27)
Non-Patent Literature Citations (3)
Entry |
Singh et al., Martensitic Transformation and Diffusional Stabilization of Martensite in High Strength Cobalt Alloy, Jul. 1987. |
Slaney et al., Development of Multiphase Alloy MP159 Using Experimental Statistics, Metallography 16:137-160 (1983). |
Guard et al., Alloying Behavior of Ni.sub.3 Al (Gamma Prime Phase), Transactions of the Metallurgical Society of AIME, vol. 215, Oct. 1959, 803. |
Continuations (2)
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Number |
Date |
Country |
Parent |
358959 |
May 1989 |
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Parent |
110132 |
Oct 1987 |
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