Pore structures of high-porosity NiTi alloys made from elemental powders with NaCl temporary space-holders

摘要

The unusual pseudo-elasticity and shape memory effect make NiTi alloys promising energy absorption materials. In the present study, powders of Ti, Ni and NaCl particles were mixed and cold-pressed into green ingots and green ingots were then desalted and sintered in vacuum to form high-porosity NiTi alloy specimens with porosity up to 90%. Microstructure observation shows that two kinds of pores with sizes of 200-400 urn and 10-50 μm respectively are well-distributed in these high-porosity NiTi alloys. Characteristics of pores were studied and formation mechanism was discussed.