HREM study of different martensitic phases in Ni–Mn–Ga alloys

The five-, seven- and ten-layered martensitic structures previously reported in Ni–Mn–Ga alloys have been investigated by high resolution electron microscopy (HREM). The observations confirm their nature as stacking of nearly close-packed planes with sequences (3 2̄), (5 2̄) and (5 5̄), in Zhdanov notation, respectively. A periodicity of 12 planes with (7 5̄) stacking sequence has also been observed.