Transformation Textures in Ni Rich NiTi Shape Memory Alloy

In-situ deformation of Ni rich NiTi shape memory alloy is characterized using synchrotron diffraction. The changes in the texture of austenite and martensite phases as a function of applied stress were systematically investigated. Development of large elastic stresses with a concomitant plastic deformation have been found to restrict the stress induced martensitic transformation. A strong lattice correspondence between the austenite and martensite phases along with a strong variant selection is reported. Further, based on the inclination of the austenite orientations to the applied loading axis, stress induced martensitic transformation or dislocation slip is activated at higher stress. This leads to the strengthening of texture components of the austenite phase and a strong variant selection in the martensite phase.