| 摘要 |
PURPOSE:To obtain a shape memory Ti-Ni alloy having bidirectional properties by carrying out soln. heat treatment at a specified temp., quenching, againg, cold working at a specified percentage and memory treatment at a prescribed temp. CONSTITUTION:A shape memory Ti-Ni alloy contg. Ni in excess and having TiNi and TiNi3 phases is subjected to soln. heat treatment at 500-1,100 deg.C, quenching, aging at 200-700 deg.C, cold working at <=60% and memory treatment at <=700 deg.C. By the cold working after the aging, orientation different from that of TiNi3 grains obtd. by only aging under constraint is obtd., so the direction of martensite transformation during cooling is controlled. By this method, satisfactory bidirectional properties are provided to a coil spring or the like.
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