TiNi形状記憶合金線材の繰返し変形と回転曲げ疲労

抄録

In order to investigate cyclic deformation and fatigue of a TiNi shape-memory alloy wire, rotating-bending fatigue tests were carried out at various strain amplitudes, temperatures and rotational speeds in air and in water. The results were summarized as follows. (1) If strain amplitude was found in the rhombohedral-phase transformation region, the fatigue life was longer than 10⁷ cycles. The deformation properties did not change under cyclic deformation. (2) If strain amplitude was found in the martensitic transformation region, the fatigue life was shorter than 10⁵ cycles. The higher the temperature, the shorter the fatigue life. (3) The rotational speed did not affect the fatigue life in water. The higher the rotational speed, the shorter the fatigue life in air.