Cyclic Deformation and Fatigue of a TiNi Shape-Memory Alloy Wire Subjected to Rotating-Bending

摘要

The cyclic deformation and fatigue of a TiNi shapememoryalloy wire was studied by carrying out rotatingbendingfatigue tests at various strain amplitudes,temperatures and rotational speeds in air and in water. Theresults were summarized as follows: (1) for strain amplitudesin the rhombohedral-phase transformation region, the fatiguelife was longer than lo7 cycles and the deformation propertiesdid not change under cyclic deformation; (2) for the strainamplitudes in the martensitic transformation region, thefatigue life was shorter than 10' cycles and the higher thetemperature, the shorter was the fatigue life; (3) the rotationalspeed did not affect the fatigue life in water but a higherrotational speed led to a shorter fatigue life in air.