Dynamic imaging of twin formation in NiMnGa based magnetic shapememory alloys under cyclic magnetic field.

Magnetic shape memory alloys (MSMA) are a unique class of material which produce huge elongation (up to 6%) upon the application of a magnetic field. This combined with their fast response makes them ideal for actuator applications. They achieve these unique properties through a deformation mechanism called twinning. Twinning is an important phenomenon which is widespread in metals and alloys. Because of the high speed of twinning these are often studied after the phenomenon has occurred. We are proposing a new stroboscopic imaging method to directly view the twinning phenomenon in magnetic shape memory alloys while the material undergoes twinning in a cyclic way. In a first of its kind experiment, we will be using a custom made rig to apply a cyclic magnetic field while synchronously collecting 4D neutron data to elucidate the dynamic nature of the twinning phenomenon.