Thermally induced fracture of single crystal Ni–Mn–Ga ferromagnetic shape memory alloy

Ni–Mn–Ga is prone to fracture when being thermally cycled. This is very different from other shape memory alloys having thermoelastic phase transformations. During thermal cycling, the cracks propagated by self-propagation, branching, microcracks nucleation, as well as interactions between the cracks. A qualitative description on the crack propagation and subsequent crack network formation is suggested. The mechanism of thermally induced brittleness is discussed.