Nickel-based superalloy and parts made from said superalloy
A nickel superalloy has the following composition, the concentrations of the different elements being expressed as wt-%: Formula (I), the remainder consisting of nickel and impurities resulting from the production of the superalloy. In addition, the composition satisfies the following equation, wherein the concentrations of the different elements are expressed as atomic percent: Formula (II).
1. A process for the preparation of a part comprising manufacturing a part from a nickel-based superalloy of the following composition, the contents of the various elements being expressed as weight percentages:
1.3%≤Al≤2.8%;
trace amounts≤Co≤11%;
14%≤Cr≤17%;
trace amounts≤Fe≤12%;
2%≤Mo≤5%;
0.5%≤Nb+Ta≤2.5%;
2.5%≤Ti≤4.5%;
1%≤W≤4%;
0.0030%≤B≤0.030%;
trace amounts≤C≤0.1%;
0.01%≤Zr≤0.06%;
the remainder consisting of nickel and impurities resulting from the production,
and such that the composition satisfies the following equations wherein the contents are expressed as atomic percentages:
8≤Al at %+Ti at %+Nb at %+Ta at %≤11
0.7≤(Ti at %+Nb at %+Ta at %)/Al % at %≤1.3,
wherein the superalloy comprises a gamma′ phase fraction comprised between 30 and 44%, and the solvus of the gamma′ phase of the superalloy is less than 1,145° C.
2. The process according to claim 1 , wherein the composition of the nickel-based superalloy satisfies the following equation wherein the contents are expressed as atomic percentages:
1≤(Ti at %+Nb at %+Ta at %)/Al at %≤1.3
3. The process according to claim 1 , wherein the nickel-based superalloy contains between 3.6 and 120 of Fe, as weight percentages.
4. The process according to claim 1 , wherein the composition of the nickel-based superalloy is, expressed as weight percentages:
1.3%≤Al≤2.80;
7%≤Co≤11%;
14%≤Cr≤17%;
3.6%≤Fe≤9%;
2%≤Mo≤5%;
0.5%≤Nb+Ta≤2.5%;
2.5%≤Ti≤4.5%;
1%≤W≤4%;
0.0030%≤B≤0.030%;
trace amounts≤C≤0.1%;
0.01%≤Zr≤0.06%;
and said composition satisfies the following equations wherein the contents are expressed as atomic percentages:
8≤Al at %+Ti at %+Nb at %+Ta at %≤11
0.7≤(Ti at %+Nb at %+Ta at %)/Al at %≤1.3
the remainder consisting of nickel and of impurities resulting from the production.
5. The process according to claim 4 , wherein the composition of the nickel-based superalloy satisfies the following equation wherein the contents are expressed as atomic percentages:
1≤(Ti at %+Nb at %+Ta at %)/Al at %≤1.3.
6. The process according to claim 4 , wherein the composition of the nickel-based superalloy is, expressed as weight percentages:
1.8%≤Al≤2.8%;
7%≤Co≤10%;
14%≤Cr≤17%;
3.6%≤Fe≤7%;
2%≤Mo≤4%;
0.5%≤Nb+Ta≤2%;
2.8%≤Ti≤4.2%;
1.5%≤W≤3.5%;
0.0030%≤B≤0.030%;
trace amounts≤C≤0.07%;
0.01%≤Zr≤0.06%;
and said composition satisfies the following equations wherein the contents are expressed as atomic percentages:
8≤Al at %+Ti at %+Nb at %+Ta at %≤11
0.7≤(Ti at %+Nb at %+Ta at %)/Al at %≤1.3
the remainder consisting of nickel and of impurities resulting from the production.
7. The process according to claim 6 , wherein the composition of the nickel-based superalloy satisfies the following equation wherein the contents are expressed as atomic percentages:
0.7≤(Ti at %+Nb at %+Ta at %)/Al at %≤1.15.
8. The process according to claim 6 , wherein the composition of the nickel-based superalloy satisfies the following equation wherein the contents are expressed as atomic percentages:
1≤(Ti at %+Nb at %+Ta at %)/Al at %≤1.3.
9. The process according to claim 1 , wherein the Cr content (expressed as an atomic percentage) of the nickel-based superalloy is, in the gamma matrix at 700° C., greater than 24 at %.
10. The process according to claim 1 , wherein the Mo+W content (expressed as an atomic percentage) of the nickel-based superalloy is ≥2.8 at % in the gamma matrix.
11. The process according to claim 1 , wherein the manufacturing of the part comprises vacuum induction melting of the nickel-based superalloy.
12. The process according to claim 11 , wherein the manufacturing of the part further comprises remelting the nickel-based superalloy after vacuum induction melting.
13. The process according to claim 12 , wherein the remelting comprises vacuum arc remelting.
14. The process according to claim 1 , wherein the manufacturing of the part is implemented by forging the nickel-based superalloy.
15. The process according to claim 14 , wherein forging is at least partly implemented at a temperature above the gamma′ solvus temperature of the alloy.
16. The process according to claim 14 , wherein forging is at least partly implemented at a temperature above 1,100° C.
17. The process according to claim 15 , wherein forging is at least partly implemented at a temperature between the gamma′ solvus temperature of the alloy and the melting onset temperature.
18. The process according to claim 1 , comprising providing an ingot of said nickel-based superalloy and hot shaping said ingot.
19. The process according to claim 18 , comprising remelting and homogenizing the ingot at temperatures higher than 1,000° C. before hot shaping.
20. The process according to claim 1 , wherein the prepared part is a component of an aeronautical or land gas turbine.
21. The process according to claim 1 , wherein the manufacturing of the part is implemented by powder metallurgy.
22. The process according to claim 1 , wherein the superalloy comprises a gamma′ phase fraction comprised between 32 and 42%, and the solvus of the gamma′ phase of the superalloy is less than 1,145° C.