Twin variant reorientation in single-crystal Ni–Mn–Ga during quasi-static mechanical compression was studied using in situ neutron diffraction. The volume fraction of reoriented twin variants for different stress amplitudes were obtained from the changes in integrated intensities of high-order neutron diffraction peaks. It was shown that, during compressive loading, some 85% of the twins were reoriented parallel to the loading direction resulting in a maximum pseudoplastic strain of about 5.5%, which was in agreement with measured macroscopic strain.

In situ Neutron Diffraction Study of Twin Reorientation and Pseudoplastic Strain in Ni–Mn–Ga Single Crystals. A.Pramanick, K.An, A.D.Stoica, X.L.Wang: Scripta Materialia, 2011, 65[6], 540-3