Ti-Ni-based shape-memory alloy and method of manufacturing same

Abstract

To remarkably improve shape-memory properties without the need for strictly controlling the composition, the present invention provides a Ti—Ni-based shape-memory alloy having a titanium content within a range of from 50 to 55 atomic %, which comprises an amorphous alloy heat-treated at a temperature of from 600 to 800 K, in which subnanometric precipitates generating coherent elastic strains are formed and distributed in the bcc parent phase(B2).

What is claimed is:  
     
         1 . A method of manufacturing a Ti—Ni-based shape-memory alloy having a titanium content within a range of from 50 to 66 atomic %, which comprises the step of forming and distributing a nanometer-scale precipitate generating a coherent elastic strain in a mother phase through a heat treatment of an amorphous Ti—Ni-based alloy at a temperature within a range of from 600 to 800 K.  
     
     
         2 . The manufacturing method as claimed in  claim 1 , wherein said heat treatment is carried out in a single run.  
     
     
         3 . The manufacturing method as claimed in  claim 1 , wherein said alloy is in a thin film shape.  
     
     
         4 . The manufacturing method as claimed in  claim 2 , wherein said alloy is in a thin film shape.