固溶温度对SPS烧结Ti-24Nb-4Zr-8Sn合金组织和力学性能的影响

Effect of solution temperature on microstructure and mechanical properties of Ti-24Nb-4Zr-8Sn alloy prepared by spark plasma sintering

利用放电等离子烧结技术(SPS)制备了生物医用Ti-24Nb-4Zr-8Sn合金,研究了固溶温度对合金显微组织和力学性能的影响。结果表明:合金在相变点下(750℃)固溶后,显微组织主要由β相、初生α相和次生α″相组成,当固溶温度升至相变点附近(775℃)时,β晶粒尺寸显著增大,晶界初生α相厚度和数量均明显减小,β晶粒上弥散分布着大量细针状与颗粒状的次生α″相;随着固溶温度的进一步升高,晶界α相厚度和数量减小并逐渐连续呈网状,β晶粒内部次生α″相不均匀析出且数量逐渐减少;与烧结态相比,合金强度和弹性模量随固溶温度的提高呈先升高后降低趋势,而塑韧性逐渐提高。

Biomedical Ti-24Nb-4Zr-8Sn alloys were prepared by spark plasma sintering. The effect of solution temperature on microstructure and mechanical properties of the alloy was investigated. The results indicate that the alloy after solution treatment at 750 ℃ are composed ofβ phase,primary α phase and secondary α″ martensite. The grain size of β phase increased and the thickness of grain boundary α phase decreased significantly aroud the phase transformation temperature（ 775 ℃）,while needle and granular α″ phases precipitated within βgrains. With the solution temperature increased,while the number of heterogeneous secondary α phase and the thickness of grain boundary αphase which generated ordering phenomenon decreased. Compared to the sintered state,the compressive strength and elasticity modulus increased at first and then decreased with the increase of solution temperature,while the ductility of alloy increased compared with the assintered.