Martensitic Transformation Behaviors of Compositionally Graded Ti-Ni-Based Shape Memory Alloys

Abstract

In this study, we demonstrate a simple and effective way to fabricate functionally graded TiNi-based alloys with linear variations of composition and martensitic transformation behavior. Ti50Ni50 and Ti50Ni35Cu15 alloy strips were fabricated through a melt overflow process. The compositionally graded diffusion couple was fabricated by annealing two strips of different alloy compositions after being placed face to face in a pressing graphite mold. The mechanical properties and martensitic transformation behaviour of the diffusion couple were analysed by tensile test and DSC. The compositionally graded specimens exhibited unique superelastic property and wide martensitic formation temperature range. Such mechanical and thermal behaviors of the compositionally graded TiNi-based alloy offer good function and controllability for actuators.