Oxidation resistant superalloy

Abstract

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 well-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:
 15.5 to 18.5 Cr;   14.0 to 15.5 Co;   2.5 to 3.5 Mo;   2.0 to 3.5 Al;   4.0 to 5.5 Ti;   0.5 to 2.0 W;   0 to 1.5 Hf;   0 to 2.0 Fe;   0 to 1.0 Si;   0.01 to 0.1 B;   0 to 0.1 Zr;   0.03 to 0.20 C;   0 to 0.5 at least one rare earth elements selected from the group of Y, La, Ce, Nb, Dy, Pr, Sm, and Gd;   less than 0.1 S; and   balance formed from Ni.   
     
     
         2 . The superalloy of  claim 1 , wherein the superalloy expressed in weight percentages consisting essentially of:
 15.5 to 16.5 Cr;   14.0 to 15.5 Co;   2.75 to 3.25 Mo;   2.25 to 2.75 Al;   4.75 to 5.25 Ti;   1.0 to 1.5 W;   0 to 1.0 Hf;   0 to 0.5 Fe;   0 to 0.5 Si;   0.01 to 0.02 B;   0.025 to 0.08 Zr;   0.03 to 0.10 C;   0 to 0.2 at least one rare earth elements selected from the group 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:
 15.5 to 16.5 Cr;   14.25 to 14.75 Co;   2.80 to 3.20 Mo;   2.30 to 2.60 Al;   4.80 to 5.20 Ti;   1.2 to 1.5 W;   0.10 to 0.15 Hf;   O to 0.2 Fe;   0.10 to 0.15 Si;   0.01 to 0.02 B;   0.025 to 0.050 Zr;   0.03 to 0.04 C;   250 to 750 ppm at least one rare earth elements selected from the group of Y, La, Ce, Nb, Dy, Pr, Sm, and Gd;   less than 2 ppm S; and   the balance formed from Ni.