Enhancement of fatigue life in TiNi shape memory alloy by ultrasonic shot peening

Abstract

The fatigue property of shape memory alloy (SMA) is one of the most important subjects in view of evaluating functional characteristics of SMA elements. In the present study, ultrasonic shot peening (USP) was applied to induce compressive residual stress on the surface layer of TiNi SMA tape and the influence of USP on the bending fatigue life was investigated. The fatigue life of USP-treated tape is longer than that of the asreceived tape. The fatigue life of the tape USP-treated with high coverage is longer than that with low coverage. The fatigue life of the USPtreated tape increases in proportion to the hardness on the surface of the tape.