Ternary Ti-Ni-Cu Shape Memory Alloy and Process for Producing Same

Abstract

An amorphous Ti—Ni—Cu alloy comprising from 44 to 49 atomic % of Ti, from 20 to 30 atomic % of Cu, and the balance being Ni and unavoidable elements is heated at 500 to 700° C. for a period of time not exceeding 100 hours to crystallize the amorphous alloy.

1 - 5 . (canceled) 
     
     
         6 . A Ti—Ni—Cu shape memory alloy, containing Ti in amount of 44 atomic % to 49 atomic %, Cu in amount of 20 atomic % to 30 atomic % and the rest consisting of Ni and inevitable impurities, wherein TiNiCu phases or TiCu phases sized 500 nm or less precipitate in a Ti(Ni,Cu) crystal grain whose grain size is 2 μm or less. 
     
     
         7 . A method of producing a Ti—Ni—Cu shape memory alloy, wherein an amorphous Ti—Ni—Cu alloy, which contains Ti in amount of 44 atomic % to 49 atomic %, Cu in amount of 20 atomic % to 30 atomic % and the rest consisting of Ni and inevitable impurities, is crystallized by heat treatment. 
     
     
         8 . The method of producing a Ti—Ni—Cu shape memory alloy as claimed in  claim 7 , wherein a temperature range of the heat treatment is 500° C. to 700° C. 
     
     
         9 . The method of producing a Ti—Ni—Cu shape memory alloy as claimed in  claim 7 , wherein time of the heat treatment is not beyond 100 hours. 
     
     
         10 . The method of producing a Ti—Ni—Cu shape memory alloy as claimed in  claim 8 , wherein time of the heat treatment is not beyond 100 hours.