Methods for improving mechanical properties of a beta processed titanium alloy article

Abstract

Methods for improving mechanical properties of beta processed, alpha-beta titanium alloy articles involving forging the alloy article above the beta transus to produce a post final forged article, subjecting the post final forged article to a post-forged cooling process to produce a post-forged cooled article, solution heat treating the post-forged cooled article to a temperature below the beta transus to produce a solution heat treated article, subjecting the solution heat-treated article to a controlled post-solution cooling process to produce a post-solution cooled article, and alpha phase precipitation treating the post-solution cooled article to obtain a final article having an average elongation value of at least about 3%.

1 . A method for improving mechanical properties of beta processed, alpha-beta titanium alloy articles comprising:
 forging the alloy article above the beta transus to produce a post final forged article;   subjecting the post final forged article to a post-forged cooling process to produce a post-forged cooled article;   solution heat treating the post-forged cooled article to a temperature below the beta transus to produce a solution heat treated article;   subjecting the solution heat-treated article to a controlled post-solution cooling process to produce a post-solution cooled article; and   alpha phase precipitation treating the post-solution cooled article to obtain a final article having an average elongation value of at least about 3%.   
   
   
       2 . The method of  claim 1  comprising forging the alloy article to a temperature of from about 1745° F. to about 1825° F. (about 952° C. to about 996° C.). 
   
   
       3 . The method of  claim 2  comprising solution heat-treating the post-forged cooled article to a temperature of from about 165° F. to about 225° F. (about 92° C. to about 125° C.) below the beta transus for about 4 hours. 
   
   
       4 . The method of  claim 3  wherein the controlled post-solution cooling process comprises cooling the solution heat-treated article at a controlled post-solution cooling rate of from about 50° F./minute to about 200° F./minute (about 28° C./minute to about 111° C./minute). 
   
   
       5 . The method of  claim 4  comprising alpha phase precipitation treating the post-solution cooled article at a temperature of from about 1100° F. to about 1350° F. (593° C. to about 732° C.) for about 8 hours. 
   
   
       6 . The method of  claim 5  wherein the final article having an average elongation value of from about 5% to about 5.8% 
   
   
       7 . The method of  claim 6  wherein the titanium alloy article comprises Ti-6Al-2Sn-4Zr-6Mo. 
   
   
       8 . A method for improving mechanical properties of a Ti-6Al-2Sn-4Zr-6Mo alloy article having a beta transus of about 1735° F. (about 946° C.) comprising:
 forging the alloy article above the beta transus to produce a post final forged article;   subjecting the post final forged article to a post-forged cooling process to produce a post-forged cooled article;   solution heat treating the post-forged cooled article to a temperature below the beta transus to produce a solution heat treated article;   subjecting the solution heat-treated article to a controlled post-solution cooling process to produce a post-solution cooled article; and   alpha phase precipitation treating the post-solution cooled article to obtain a final article having an average elongation value of from about 5% to about 5.8%.   
   
   
       9 . The method of  claim 8  comprising forging the alloy article to a temperature of from about 1745° F. to about 1825° F. (about 952° C. to about 996° C.). 
   
   
       10 . The method of  claim 9  wherein the post-forged cooling process comprises cooling the post final forged article at a post-forged cooling rate of from about 150° F./minute to about 400° F./minute (about 83° C./minute to about 222° C./minute) while the temperature of the post final forged article is between about the beta transus and about 700° F. (about 371° C.). 
   
   
       11 . The method of  claim 10  comprising solution heat-treating the post-forged cooled article to a temperature of from about 165° F. to about 225° F. (about 92° C. to about 125° C.) below the beta transus for about 4 hours. 
   
   
       12 . The method of  claim 11  wherein the controlled post-solution cooling process comprises cooling the solution heat-treated article at a controlled post-solution cooling rate of from about 50° F./minute to about 200° F./minute (about 280° C./minute to about 111° C./minute). 
   
   
       13 . The method of  claim 12  comprising alpha phase precipitation treating the post-solution cooled article at a temperature of from about 1100° F. to about 1350° F. (593° C. to about 732° C.) for about 8 hours. 
   
   
       14 . A method for improving mechanical properties of a Ti-6Al-2Sn-4Zr-6Mo alloy article having a beta transus of about 1735° F. (about 946° C.) comprising:
 forging the alloy article to a temperature of from about 1745° F. to about 1825° F. (about 952° C. to about 996° C.) to produce a post final forged article;   subjecting the post final forged article to a post-forged cooling process comprising cooling the post-forged article at a post-forged cooling rate of from about 150° F./minute to about 400° F./minute (about 83° C./minute to about 222° C./minute) while the temperature of the post final forged article is between about the beta transus and about 700° F. (about 371° C.) to produce a post-forged cooled article;   solution heat treating the post-forged cooled article to a temperature of from about 165° F. to about 225° F. (about 92° C. to about 125° C.) below the beta transus for about 4 hours to produce a solution heat treated article;   subjecting the solution heat-treated article to a controlled post-solution cooling process comprising cooling the solution heat-treated article at a controlled post-solution cooling rate of from about 50° F./minute to about 200° F./minute (about 280° C./minute to about 111° C./minute) to produce a post-solution cooled article; and   alpha phase precipitation treating the post-solution cooled article at a temperature of from about 1100° F. to about 1350° F. (593° C. to about 732° C.) for about 8 hours to obtain a final article having an average elongation value of from about 5% to about 5.8%.