Microstructure and martensitic transformation behavior of porous NiTi shape memory alloy prepared by hot isostatic pressing processing

Porous NiTi shape memory alloy (SMA) has been successfully prepared by hot isostatic pressing (HIP) of elemental Ni and Ti powder. The alloy has isotropic and uniform pore distribution of spherical pores ranged from 50 to 200 μm. The microstructure, martensitic transformation behavior and mechanical properties of this porous NiTi SMA aged at different conditions were studied. It has been found that the phase transformation behavior of porous NiTi SMA is similar to that of the dense Ni-rich NiTi alloys. The porous NiTi SMAs can exhibit almost complete superelasticity at human body temperature.