Method of manufacturing high strength and high ductility titanium alloy

Abstract

Disclosed is a method of manufacturing a high strength and high ductility titanium alloy. The method comprises: providing a titanium alloy having a martensite structure; and partially dynamically spheroidizing a microstructure through a thermal and mechanical treatment of the titanium alloy having the martensite structure. According to the present invention, a titanium alloy having a partially dynamically spheroidized microstructure can be manufactured to have excellent yield strength (YS) and uniform elongation (U.EL). A microstructure having lamellar structures is controlled to a microstructure where fine equiaxed structures and lamellar structures are simultaneously present by regulating a rolling direction and a deformation amount. According to the present invention, a titanium alloy can be manufactured to have an improved product (YS×U.EL) of yield strength and uniform elongation as compared with conventional heat treatment.

1 . A method of manufacturing a high strength and high-ductility titanium alloy, the method comprising:
 providing a titanium alloy having a martensite structure; and   partially dynamically spheroidizing a microstructure through a thermal and mechanical treatment of the titanium alloy having the martensite structure.   
     
     
         2 . The method of  claim 1 , wherein:
 the microstructure of the provided titanium alloy includes a lamellar martensite structure.   
     
     
         3 . The method of  claim 1 , wherein:
 during the thermal and mechanical treatment,   the titanium alloy is rolled at a deformation temperature of 775° C. to 875° C., a deformation rate of 0.07 s −1  to 0.13 s −1 , and a deformation amount of −0.2 to −1.6.   
     
     
         4 . The method of  claim 3 , wherein:
 during the thermal and mechanical treatment,   the titanium alloy is rolled at a deformation temperature of 800° C., a deformation rate of 0.1 s −1 , and a deformation amount of −0.2 to −1.6.   
     
     
         5 . The method of  claim 1 , wherein:
 the rolling is uni-directional rolling.   
     
     
         6 . The method of  claim 5 , wherein:
 fine equiaxed structures and lamellar structures are simultaneously present in the microstructure of the titanium alloy through the partial dynamic spheroidization.   
     
     
         7 . The method of  claim 2 , wherein:
 the rolling is uni-directional rolling.   
     
     
         8 . The method of  claim 7 , wherein:
 fine equiaxed structures and lamellar structures are simultaneously present in the microstructure of the titanium alloy through the partial dynamic spheroidization.   
     
     
         9 . The method of  claim 3 , wherein:
 the rolling is uni-directional rolling.   
     
     
         10 . The method of  claim 9 , wherein:
 fine equiaxed structures and lamellar structures are simultaneously present in the microstructure of the titanium alloy through the partial dynamic spheroidization.   
     
     
         11 . The method of  claim 4 , wherein:
 the rolling is uni-directional rolling.   
     
     
         12 . The method of  claim 11 , wherein:
 fine equiaxed structures and lamellar structures are simultaneously present in the microstructure of the titanium alloy through the partial dynamic spheroidization.