In-Situ Observation of the Stress-Induced Stochastic Twin Boundary Motion in off Stoichiometric NiMnGa Single Crystal...

Stochastic motion of the type II twin boundary in off stoichiometric NiMnGa single crystal is confirmed by in-situ X-ray microdiffraction during external stress field loading. Assymmetry between tensile and compressive parts of the loading and large hysteresis loop is found. Formation of local strained regions is predecessing each boundary movement. The location of strained regions adjusts to the position of the twin boundary. Abrupt motion of the boundary correlates with the corresponding spikes at the load/displacement curve.