烧结温度对多孔TiNi合金微观结构和力学性能的影响

Effect of sintering temperature on microstructure and mechanical properties of TiNi alloy

采用Ti、Ni纯元素混合粉末真空烧结技术制备了孔隙分布均匀且力学性能优良的多孔TiNi形状记忆合金(SMA),并利用X射线衍射仪、金相显微镜、扫描电子显微镜及电子万能试验机研究对比了900、950、1000、1050、1100和1150℃6个不同烧结温度对合金微观结构和力学性能等的影响。结果表明,烧结温度是影响多孔TiNi合金性能的决定性因素,通过调节烧结温度可有效调节合金的相组成、孔隙特征和力学性能。随着烧结温度的升高,合金的次生相逐渐减少,相组成成分更加均一;致密度不断提高,由59%上升到62%,孔隙分布愈加均匀且孔隙形貌由多尖角形趋于球形化;抗拉强度由72.43MPa增加到160.12MPa,弹性模量从1.08GPa增加到1.32GPa。

Porous titanium-nickel （TiNi） shape memory alloy （SMA） with homogeneous pore distribution and good mechanical properties was fabricated by pure element powders sintering process. Effect of sintering tem- perature on microstructure and mechanical properties of TiNi alloy was studied by X-ray diffraction （XRD）, metallurgical microscope, scanning electron microscopy （SEM） analysis and electronic universal testing machine at 900, 950, 1000, 1050, 1100 or 1150℃. The results showed that sintering temperature is the determinants af- fecting the properties of porous TiNi alloy, then phase composition, pore characteristic and mechanical proper- ties are improved by change of sintering temperature. With the increase of the temperature from 900 to 1150℃, secondary phase disappeared and phase composition is more homogeneous. The relative density values of porous TiNi increases from 59% to 62%. Tensile strength values increases from 72.43 to 160. 12MPa, and elastic modulus values increases from 1.08 to 1.32GPa.