Morphological characteristics of the orthorhombic martensite in a shape memory ti-ni-cu alloy

Abstract

Morphological characteristics of the orthorhombic martensite in a Ti-Ni-Cu shape memory alloy have been investigated and the following have been found: (1) In the cubic (B2) to orthorhombic transformation of the Ti-Ni-Cu alloy, no lattice invariant shear is needed. This is due to the fact that one of the principal distortion of transformation is nearly zero. (2) The experimentally obtained habit planes are {334} of the parent lattice and agree very well with the prediction by the phenomenological theory of martensite. (3) Self-accommodation in the orthorhombic martensite is achieved by combination of three variants around each one of the <111 > axes of the parent lattice. © 1989, The Iron and Steel Institute of Japan. All rights reserved.