An antiphase boundary-like structure in the B19 martensite of the Ti-Pd alloy was investigated by transmission electron microscopy. High-resolution and high-angle annular dark-field scanning transmission electron microscopy images revealed the presence of an antiphase boundary-like contrast along the (001) basal plane of the B19 martensite. The contrast was not inherited from the antiphase boundary with a displacement vector of the type, R = ½<111>, in the B2 parent phase. This suggested that the boundary was produced by the local heterogeneity of atomic movements during the martensitic transformation. Therefore, it was proposed that the antiphase boundary-like structure in B19 martensite should be defined as being a displacive transformation-induced antiphase boundary.

Crystallography and Morphology of Antiphase Boundary-Like Structure Induced by Martensitic Transformation in Ti-Pd Shape Memory Alloy. M.Matsuda, T.Hara, M.Nishida: Materials Transactions, 2008, 49[3], 461-5