Mechanical and shape-memory behavior of homogenized NiTiHfPd alloys

Abstract

Mechanical behavior of a Ni45.3Ti34.7Hf15Pd5 (at.%) alloy was systematically analyzed after homogenization treatment at 1050°C for 4 h. Shape-memory behavior under a wide range of compressive stress levels from 100 to 1000 MPa was investigated through constant-stress thermal cycling experiments. The alloys showed a reversible strain of 2.5% against a huge stress of 1 GPa. Superelastic behavior was observed in a large temperature window of 50°C–170°C. Training of the alloys resulted in hardening effect and better shape recovery in constant-temperature loading experiments at –50°C.