High porosity and large pore size shape memory alloys fabricated by using pore-forming agent (NH4HCO3) and capsule-free hot isostatic pressing

High porosity and large pore size porous NiTi shape memory alloys were successfully fabricated by using pore-forming agent (NH4HCO3) and capsule-free hot isostatic pressing process. The porosity of the fabricated porous alloys increases linearly with addition of NH4HCO3 and reaches as high as nearly 50%, and the alloys show more uniform pore distribution with most pores larger than 300 μm.