Titanium aluminide alloys

Abstract

Alloys based on titanium aluminides, such as γ (TiAl) which may be made through the use of casting or powder metallurgical processes and heat treatments. The alloys contain titanium, 38 to 46 atom % aluminum, and 5 to 10 atom % niobium, and they contain composite lamella structures with B19 phase and β phase there in a volume ratio of the B19 phase to β phase 0.05:1 and 20:1.

1 . A method for the production of an alloy, comprising:
 providing a composition that comprises titanium, 38 to 46 at % aluminum, and 5 to 10 at % niobium;   subjecting the composition to a casting or powder metallurgical technique to produce an intermediate product; and   subjecting the intermediate product to a heat treatment, the heat treatment comprising heating the intermediate product at a temperature above 900° C. for more than sixty minutes, and cooling the intermediate product at a rate of more than 0.5° C. per minute.   
   
   
       2 . The method of  claim 1  wherein the heat treatment comprises heating the intermediate product at a temperature above 1000° C. 
   
   
       3 . The method of  claim 1  wherein the heat treatment comprises heating the intermediate product at a temperature between 1000° C. and 1200° C. 
   
   
       4 . The method of  claim 1  wherein the heat treatment comprises heating the intermediate product at said temperature above 900° C. for more than 90 minutes. 
   
   
       5 . The method of  claim 1  wherein the heat treatment comprises heating the intermediate product at a temperature above 1000° C. for more than 90 minutes. 
   
   
       6 . The method of  claim 1 , comprising cooling the intermediate product at a rate of 1° C. per minute to 20° C. per minute. 
   
   
       7 . The method of  claim 1 , comprising cooling the intermediate product at a rate of 1° C. per minute to 10° C. per minute.