High porosity and high-strength porous NiTi shape memory alloys with controllable pore characteristics

High porosity and high-strength porous NiTi alloys with controllable pore characteristics were successfully fabricated by using urea as a temporary space-holder and conventional sintering. The use of uniform spherical urea particles has hardly any effect on microstructures of the fabricated porous NiTi alloys, while it brings higher porosity and strength as well as more steady superelasticity over those fabricated by using carbonate. The fabricated porous NiTi alloys show the highest strength among those made by several different methods.