Mechanical Behavior of Porous Ni-Ti Alloy Produced by Bulk Combustion Synthesis Method for Bone Surgery

Mechanical property of porous nickel-titanium alloy produced by volumetric combustion synthesis (VCS) for bone surgery applications is reported in this paper. Stress-strain behavior of the alloy is determined by uniaxial tension test. Superelastic diagram of the porous alloy is compared with that of the solid material cooled from austenite stability temperature. Due to movements of the dislocations، growth of the nucleation sites and thinning of the martensite plates during cooling، plastic deformation and necking behavior of these materials are principally different from that of the ordinary materials. Elastic modulus and yield stress of the material have nonlinear relationship with porosity percentage and obey the following correlations  and The stress-strain curves of the alloy show more than 6 percent elongation before rupture، even with 30 percent porosity. A comparison of the cleavage surfaces of the combustion synthesis samples with those of the powder metallurgical ones indicate great influence of production process on fracture mechanism.