Corrosion resistant superalloy with improved oxidation resistance

Abstract

An improved nickel-based superalloy having high corrosion and oxidation resistance and good compatibility with a thermal barrier coating. The enhanced oxidation resistance and compatibility with the thermal barrier coating results from the inclusion of two or more rare earth elements. The superalloy is useful for the fabrication of components for a gas turbine.

1 . A nickel-based superalloy consisting essentially of materials as expressed in weight percentages: 
 21.0 to 24.0 Cr;    18.0 to 20.0 Co;    0 to 0.5 Mo;    1.5 to 2.5 W;    1.0 to 2.0 Ta;    1.5 to 2.3 Al;    3.4 to 4.0 Ti;    0.7 to 1.2 Nb;    0.05 to 0.3 Hf;    0.05 to 0.3 Si;    0.002 to 0.008 B;    0.010 to 0.040 Zr;    0.10 to 0.20 C;    0.001 to 0.1 of a mixture of two or more rare earth elements selected from the group of La, Ce, Nb, Dy, Pr, Sm and Gd; and    and the balance formed from Ni.    
     
     
         2 . The superalloy of  claim 1 , wherein the alloy consisting essentially of materials as expressed in weight percentages: 
 22.0 to 22.8 Cr;    18.5 to 19.5 Co;    0 to 0.2 Mo;    1.8 to 2.2 W;    1.3 to 1.5 Ta;    1.8 to 2.0 Al;    3.6 to 3.8 Ti;    0.9 to 1.1 Nb;    0.1 to 0.25 Hf;    0.15 to 0.25 Si;    0.004 to 0.006 B;    0.020 to 0.030 Zr;    0.13 to 0.17 C;    0.01 to 0.05 of a mixture of two or more rare earth elements selected from the group of La, Ce, Nb, Dy, Pr, Sm, and Gd; and    and the balance formed from Ni.    
     
     
         3 . The superalloy of  claim 1 , wherein the alloy wherein the alloy consisting essentially of materials as expressed in weight percentages: 
 22.4. Cr;    19.0 Co;    2.0 W;    1.4 Ta;    1.9 Al;    3.7 Ti;    1.0 Nb;    0.2 Hf;    0.2 Si;    0.005 B;    0.025 Zr;    0.15 C;    0.02 of a mixture of two or more rare earth elements selected from the group of La, Ce, Nb, Dy, Pr, Sm, and Gd; and    and the balance formed from Ni.