Superalloy forming highly adherent chromia surface layer
A nickel-based superalloy that forms a chromia scale in an oxidizing environment is disclosed. The alloy provides good oxidation resistance at temperatures below 900° C. in a dry or moist atmosphere. The superalloy is suited for components of gas or steam turbine engines including blades and vanes.
1 . A nickel-based superalloy expressed in weight percentages consisting essentially of:
10 to 25 Cr;
5 to 25 Co;
2.0 to 6.0 Mo;
0.5 to 4.0 Al;
1.0 to 4.0 Ti;
0 to 3 Hf;
0 to 10 Fe;
0 to 1 Si;
0 to 0.10 B;
0 to 0.20 Zr;
0 to 0.20 C;
0 to 0.5 at least one rare earth element selected from the group consisting of Y, La, Ce, Nb, Dy, Pr, Sm, and Gd;
less than 100 ppm S; and
balance formed from Ni.
2 . The superalloy of claim 1 , wherein the superalloy expressed in weight percentages consisting essentially of:
18 to 21 Cr;
12.0 to 15.0 Co;
3.5 to 5.0 Mo;
1.2 to 1.6 Al;
2.75 to 3.25 Ti;
0 to 0.5 Hf;
0 to 2 Fe;
0 to 0.5 Si;
0.003 to 0.010 B;
0.02 to 0.08 Zr;
0.03 to 0.10 C;
0 to 0.2 of at least one rare earth element selected from the group consisting of Y, La, Ce, Nb, Dy, Pr, Sm, and Gd;
less than 10 ppm S; and
the balance formed from Ni.
3 . The superalloy of claim 1 , wherein the superalloy expressed in weight percentages consisting essentially of:
18.5 Cr;
13.0 to 14.0 Co;
4.0 to 4.4 Mo;
1.30 to 1.50 Al;
2.80 to 3.20 Ti;
0.05 to 0.15 Hf;
0 to 0.2 Fe;
0.05 to 0.15 Si;
0.008 B;
0.06 Zr;
0.07 C;
0.02 of a mixture of at least one rare earth element selected from the group consisting of Y, La, Ce, Nb, Dy, Pr, Sm, and Gd;
with less than 4 ppm S; and
the balance formed from Ni.