PROCESS FOR PRODUCING A FORGED COMPONENT FROM A TiAl ALLOY AND COMPONENT PRODUCED THEREBY

Abstract

A process for producing a component from a TiAl alloy by two-stage isothermal forging and to a component produced thereby. The process comprises a first isothermal forging of a component precursor at a temperature of at least about 1180° C., an intermediate annealing of the forged precursor at a temperature ranging from about 1130° C. to 1170° C. for about 1 to 8 hours and a subsequent second isothermal forging at a temperature of at least about 1180° C. with a degree of forming which is lower than the degree of forming in the first isothermal forging.

What is claimed is: 
     
         1 . A process for producing a component from a TiAl alloy by two-stage isothermal forging, wherein the process comprises:
 (a) first isothermal forging of a component precursor at a temperature of at least 1180° C. and with a first total degree of forming;   (b) intermediate annealing of the forged precursor of (a) at a temperature ranging from 1130° C. to 1170° C. for 1 to 8 hours;   (c) second isothermal forging of the intermediately annealed precursor of (b) at a temperature of at least 1180° C. and with a second total degree of forming which is lower than the first total degree of forming.   
     
     
         2 . The process of  claim 1 , wherein the TiAl alloy is a TNM alloy. 
     
     
         3 . The process of  claim 1 , wherein the temperature in (a) is at least 1190° C. 
     
     
         4 . The process of  claim 1 , wherein the temperature in (a) is at least 1200° C. 
     
     
         5 . The process of  claim 1 , wherein the temperature in (c) is at least 1190° C. 
     
     
         6 . The process of  claim 4 , wherein the temperature in (c) is at least 1200° C. 
     
     
         7 . The process of  claim 1 , wherein the degree of forming in (a) is at least 0.55. 
     
     
         8 . The process of  claim 4 , wherein the degree of forming in (a) is at least 0.6. 
     
     
         9 . The process of  claim 1 , wherein the temperature in (b) ranges from 1135° C. to 1165° C. 
     
     
         10 . The process of  claim 4 , wherein the temperature in (b) ranges from 1140° C. to 1160° C. 
     
     
         11 . The process of  claim 1 , wherein (b) is conducted for at least 1.5 hours and/or for no longer than 7.5 hours. 
     
     
         12 . The process of  claim 1 , wherein after (c) at least one further heat treatment is conducted. 
     
     
         13 . The process of  claim 12 , wherein the further heat treatment is conducted at a temperature above a γ solvus temperature of the TiAl alloy. 
     
     
         14 . The process of  claim 12 , wherein the further heat treatment is conducted at a temperature below a γ solvus temperature of the TiAl alloy. 
     
     
         15 . The process of  claim 12 , wherein the further heat treatment is conducted at a temperature in the range from a γ solvus temperature to 30° C. above the γ solvus temperature of the TiAl alloy. 
     
     
         16 . The process of  claim 12 , wherein the further heat treatment is conducted at a temperature of from 10° C. to 50° C. below the γ solvus temperature of the TiAl alloy. 
     
     
         17 . The process of  claim 12 , wherein the further heat treatment is conducted for from 20 to 180 minutes. 
     
     
         18 . The process of  claim 12 , wherein the further heat treatment is followed by a cooling. 
     
     
         19 . The process of  claim 18 , wherein the cooling is followed by a further heat treatment. 
     
     
         20 . A component produced by the process of  claim 1 .