Phase transformation characteristics and mechanical characterization of nitinol synthesized by laser direct deposition

Laser direct deposition, an additive manufacturing technique, has been proved to be an effective method to synthesize nitinol from elemental nickel and titanium powders for the fabrication of near-net shaped components. In this study, the experimental procedures and results are presented for understanding the phase transformation characteristics and mechanical behavior of laser synthesized nitinol. Different transformation temperatures were successfully achieved by changing the initial ratio of Ni and Ti powders coupled with post aging heat treatment. The results obtained from the uniaxial compression testing at different temperatures indicate that the samples recovered strain completely by both the shape memory and super-elastic effects. Hence, the capability of laser direct deposition technique to synthesize nitinol with required micro-structure and mechanical properties is demonstrated. (C) 2012 Elsevier B.V. All rights reserved.