Trinickel aluminide-base heat-resistant alloy

Abstract

An Ni 3 Al-base heat-resistant alloy containing, in % by weight, 6.0 to 9.0% of Al, 2.0 to 15.0% of Cr and 0.5 to 3.0% of Zr, the balance being Ni and inevitable impurities, the alloy having a metal structure comprising Ni 3 Al as the main phase thereof. When required, the alloy may further contain over 0% to not more than 5.0% of W, over 0% to not more than 3.0% of Mo, over 0% to not more than 3.0% of Nb, over 0% to not more than 0.003% of B, over 0% to not more than 0.3% of C and 0.003 to 0.03% of N, wherein the combined amount of W, Mo and Nb is up to 5.0% if at least two of these elements are present.

What is claimed is:  
     
         1 . A heat-resistant alloy excellent in creep rupture strength at high temperatures and in weldability and consisting of, in % by weight, 6.0 to 9.0% of Al, 2.0 to 15.0% of Cr and 0.5 to 3.0% of Zr, the balance being Ni and inevitable impurities, the alloy having a metal structure comprising Ni 3 Al as the main phase thereof.  
     
     
         2 . The heat-resistant alloy according to    claim 1    which contains one element selected from the group consisting of over 0% to not more than 5.0% of W, over 0% to not more than 3.0% of Mo and over 0% to not more than 3.0% of Nb.  
     
     
         3 . The heat-resistant alloy according to    claim 1    which contains up to 5.0%, in a combined amount, of at least two elements selected from the group consisting of over 0% to not more than 5.0% of W, over 0% to not more than 3.0% of Mo and over 0% to not more than 3.0% of Nb.  
     
     
         4 . The heat-resistant alloy according to    claim 1    which contains over 0% to not more than 0.3% of C and/or 0.003 to 0.03% of N.  
     
     
         5 . The heat-resistant alloy according to    claim 2    which contains over 0% to not more than 0.3% of C and/or 0.003 to 0.03% of N.  
     
     
         6 . The heat-resistant alloy according to    claim 3    which contains over 0% to not more than 0.3% of C and/or 0.003 to 0.03% of N.  
     
     
         7 . The heat-resistant alloy according to    claim 1    which contains over 0% to not more than 0.003% of B.  
     
     
         8 . The heat-resistant alloy according to    claim 2    which contains over 0% to not more than 0.003% of B.  
     
     
         9 . The heat-resistant alloy according to    claim 3    which contains over 0% to not more than 0.003% of B.  
     
     
         10 . The heat-resistant alloy according to    claim 4    which contains over 0% to not more than 0.003% of B.  
     
     
         11 . The heat-resistant alloy according to    claim 5    which contains over 0% to not more than 0.003% of B.  
     
     
         12 . The heat-resistant alloy according to    claim 6    which contains over 0% to not more than 0.003% of B.