Optimal Surface Preparation of Ni-Mn-Ga Through Micro-peening

Ni-Mn-Ga is a magnetic shape memory (MSM) alloy, which plastically deforms up to 12% when exposed to a magnetic field of sufficient strength. One of the limiting factors for the commercialization of this MSM material is its susceptibility to damage during cyclical actuation. This research investigates the effect micro-peening has on the longevity of the material. The goal of the surface preparation is to find an optimum peening impact. The impact should be strong enough to provide hardening that suppresses fatigue damage yet weak enough to retain the material’s large shape changes at relatively low magnetic fields. We present and discuss results of micro-peening experiments where we systematically vary the air pressure