Ti-Ni-Cu形状記憶合金の有効ひずみエネルギーに及ぼす冷間加工率の影響

抄録

A shape memory alloy is receiving attention in various fields. In areas such as engineering and medicine, its applications are being studied and practically used. Authors have proposed a reciprocating heat engine inorporating shape memory alloy wires. Ti-Ni alloy is practically used because it is superior to cyclic behaviors and a corrosive resistance. However, in order to enlarge the further applications, some improvements in cyclic behaviors and fatigue life are necessary. The purpose of the present paper is to investigate the effect of the cold working ratio on the cyclic behavior of functions and strain energy in Ti-41.7 at % Ni-8.5 at % Cu alloy wires. Results show that the increase of the cold working ratio is effective for improvement of functions such as recovery stress and irrecoverable strain, And the available strain energy and the thermal efficiency per cycle increase with increasing in cold working ratio. Furthermore, the degradation of available strain energy decreases with increasing in cold working ratio. However, the total available strain energy to failure increases with the decrease in cold working ratio.