Abstract:A new designed space-controlled self-propagating synthesis process was used to prepare porous NiTi shape memory alloys (SMAs) after the pretreatment of Ti powder and Ni powder. Properties including pore structures, phase composition and superelasticity of the alloys are characterized, and the biological safety was evaluated through the experiment mcludmg hemolysls test and cytotoxicity test (MTT). The results show that it is difficult to obtain SMAs with ideal pore structures without pretreating the mixed powders. After pretreating the raw powders properly, SMAs with excellent comprehensive properties can be fabricated. Nearly spherical pores with 34% porosity and diameters between 100 and 500 μm are homogeneously distributed in the alloys. The alloys are composed of single B2 and have good superelasticity. After three cyclic loading and unloading compression tests at 2.5% and 4.0% strains, no residual strain is generated. The corresponding compressive strength is 250MP and 363MPa respectively, and the elastic modulus is 15.4GPa. MTT tests show morphologies of cells in SMAs leaching solution are normal and the cytotoxicity is estimated level 1, indicating SMAs have good biological safety.