Study on Preparation of Gradient Porous NiTi Alloys by Powder Metallurgy Method
Gradient porous NiTi alloys were fabricated by powder metallurgy method using NH4HCO3 as space-holder. The effect of content and distribution of NH4HCO3 on pore characteristic, phase composition and compressive properties was studied. The results showed the content of TiNi phase increased with the decrease of the content of NH4HCO3. When the distribution of NH4HCO3 varying form 12wt%-12wt%-12wt% to 12wt%-6wt%-12wt% and 12wt%-0wt%-12wt%, the stress and elastic modulus of porous NiTi alloys increased from 228MPa to 321MP and 446MPa, from 4.8GPa to 5.6GPa and 6.8GPa, respectively. Compared with uniform porous materials, gradient porous NiTi alloy exhibited better superelasticity.
Jianzhong Wang and Jingang Qi
Q. Li et al., "Study on Preparation of Gradient Porous NiTi Alloys by Powder Metallurgy Method", Advanced Materials Research, Vols. 299-300, pp. 671-674, 2011