烧结工艺对多孔钛基合金组织与性能的影响

Effect of sintering process on the microstructure and properties of porous titanium based alloys

针对生物医用钛合金弹性模量仍远高于人骨和力学性能会随着孔隙的引入而急剧降低等问题,采用粉末冶金加造孔剂(镁锌粉)制备多孔钛基合金,研究烧结温度对其组织及性能的影响。研究结果表明,在不同烧结温度下,随烧结温度的增加,试样密度升高、孔隙率降低;多孔Ti-35Nb-7Zr-5Ta合金的相组成主要为β-Ti、α-Ti、Nb和Ta,各成分分布随烧结温度的升高更加均匀,且少量α-Ti相逐渐向β-Ti相转变,含量减少;随着烧结温度的增加,试样抗压强度由426MPa增加至689MPa,弹性模量由21.96GPa增加至27.28GPa,但由于α-Ti相向β-Ti相转变,使得弹性模量的同比增加量小于抗压强度。通过调控烧结工艺制备出的多孔Ti-35Nb-7Zr-5Ta合金具有低模量高强度的力学性能,有望用作人体骨骼替代的医用植入材料。

In view of the problems that the elastic modulus of biomedical titanium alloy is still much higher than that of human bone and the mechanical properties will decrease sharply with the introduction of pores,the porous titanium-based alloy was prepared by powder metallurgy plus pore-forming agent(magnesium-zinc powder),and the effect of sintering temperature on its organization and performance.The research results show that at different sintering temperatures,the density of the sample increases and the porosity decreases with the increase of the sintering temperature;the phase of the porous Ti-35Nb-7Zr-5Ta alloy is mainly composed of β-Ti,α-Ti,Nb,Ta Composition,with the increase of sintering temperature,the microstructure distribution is more uniform,and a small amount of α-Ti phase gradually transforms into β-Ti phase,and the content decreases;with the increase of sintering temperature,the compressive strength of the sample increases from 426MPa to 689MPa,the elastic modulus increased from 21.96GPa to 27.28GPa,but due to the transformation from α-Ti phase to β-Ti phase,the year-on-year increase of elastic modulus was less than the compressive strength.The porous Ti-35Nb-7Zr-5Ta alloy prepared by adjusting the sintering process has low modulus and high strength mechanical properties and is expected to be used as a medical implant material for human bone replacement.