Deformation twinning of B2 austenitic phase in NiTi had not been understood despite its significance. A number of experimental observations were made, but these alone cannot explain the complex shears and shuffles that produce the twin. It was proposed that twinning could occur via (¯211)[¯1¯1¯1] shear and that the proposed shuffle differed from previous work and was parallel to the twinning shear. A twin-energy barrier was established which was lower when compared with the previously proposed twinning modes, and had a magnitude of 79mJ/m2. Hydrostatic pressure was found to alter this energy barrier and the coupling of shear and shuffle mechanism.

Coupled Shear and Shuffle Modes during Twin Growth in B2-NiTi. T.Ezaz, H.Sehitoglu: Applied Physics Letters, 2011, 98[24], 241906