热等静压温度和粉末粒度对Ti2AlNb合金组织与性能的影响

采用无坩埚感应熔炼超声气体雾化法制备了成分为Ti-22Al-24Nb-0.5Mo(原子分数, %)的预合金粉末，通过预合金粉末热等静压工艺制备了Ti₂AlNb粉末冶金合金。研究结果表明，热等静压温度显著影响Ti₂AlNb粉末冶金合金的显微组织，需严格控制。为了对比研究，选取了平均粒度分别为70 μm和200 μm的两种Ti₂AlNb预合金粉末，制备坯料并测试性能，探讨了粉末粒度的选取原则，分析了粉末粒度对Ti₂AlNb粉末冶金合金显微组织和力学性能的影响。研究结果表明，粉末粒度对合金室温拉伸强度无显著影响，但会对高温拉伸强度和高温持久寿命产生显著影响，由粗粉(平均粒度200 μm)制成的合金高温持久寿命较细粉(平均粒度70 μm)的降低大约40%。

Effect of Temperature and Powder Particle Size on Mechanical Properties and Microstructure of PM Ti2AlNb Alloy Prepared via Hot Isostatic Pressing

Pre-alloyed powder of Ti-22Al-24Nb-0.5Mo (atomic fraction, %) was prepared via a two step process, i.e. electrode no crucible induction melting and then gas atomization process. Powder metallurgy (PM) Ti₂AlNb alloys was prepared through a typical hot isostatic pressing (HIPing) route. Two pre-alloyed powders with average particle sizes of 70 and 200 μm respectively were prepared and adopted to prepare PM alloys tested for comparison. The results showed that the powder particle size had no significant effect on the tensile strength at room temperature, but a significant effect on the tensile strength and rupture life time at elevated temperature. It showed that the rupture lifetime of PM Ti₂AlNb alloys made of the coarser powders was about 40% less than that of the finer powders.