限空间自蔓延法制备多孔NiTi合金及性能表征

Preparation and Performance Characterization of Porous NiTi Alloys by Space-controlled Self-propagating Method

摘要:

以Ti粉和Ni粉为原料，对粉末进行预处理后，采用限空间自蔓延工艺制备多孔NiTi合金，对合金的孔隙结构、物相和超弹性等性能进行表征，进一步通过体外细胞毒性试验(MTT法)评价合金的生物安全性能。结果表明：粉末未进行预处理时，难以获得孔隙结构理想的多孔合金。对粉末进行适当的预处理后，可以获得综合性能优异的多孔NiTi合金。合金中的孔隙分布均匀，孔隙形状近球形，孔隙率为34%，孔径为100-500 μm。合金物相由单一的B2相组成，具有良好的超弹性，在2.5%应变和4.0%应变下经过3次循环加载-卸载压缩测试，未产生残余应变。两种应变时对应的抗压强度分别为250 MP和363 MPa，弹性模量为15.4 GPa。MTT试验显示细胞形态体征正常，细胞毒性为1级，表明制备的多孔NiTi合金具有良好的生物安全性能。

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.