The microstructure of a Ni–Mn–Ga ferromagnetic shape memory alloy was characterized by transmission electron microscopy. Electron diffraction revealed that the microstructure of the alloy predominately consisted of seven-layer modulated martensite. There exists reflection-twinned relation between the martensitic variants. It was found that there were parallel and equidistant fringes at the boundary. The nature of these fringes was analysed and the results showed that the boundary fringes were caused by the elastic strains associated with the coherent interface.

Twin Boundary Structure of the Modulated Variants in a Ni–Mn–Ga Alloy. M.Han, F.F.Kong: Journal of Alloys and Compounds, 2008, 458[1-2], 218-22