M. Krishnan, Bhabha Atomic Research Centre, Mumbai, India
The microstructure of shape memory alloys is characterized by the self accommodating arrangement of martensite variants. While the self accommodating microstructures of the B19’ martensite in Ni-Ti alloys has been established to be the <111>C 3-variant plate group, there is insufficient information regarding that of the orthorhombic B19 martensite found in Ni-Ti-Cu alloys. In this study, we investigated the martensitic microstructures in the Ni41Ti50Cu9 alloy using transmission electron microscopy (TEM) and observed that the self accommodating arrangement consists of stacks of 3-variant plate groups. This paper examines the driving force for the formation of such unusual self accommodating plate groups on the basis of the crystallographic information provided by TEM.
Summary: In this study, the self accommodating microstructure of B19 martensite in the Ni
41Ti
50Cu
9 alloy was determined using transmission electron microscopy. It was observed that the self accommodating arrangement consists of stacks of 3-variant plate groups. Clustered around the {111} poles. This paper examines the driving force for the formation of this unusual self accommodating arrangement.
