粉末耐热钛合金组织性能及成形技术

采用热等静压技术及旋转电极粉,采用预合金粉粉末冶金工艺开展了粉末耐热钛合金TC11(Ti-6.5AJ-3.5Mo-1.5Zr-0.3Si)制备技术研究,研制出了全致密粉末TC11合金,通过热处理工艺研究优化粉末TC11材料的组织和性能.利用光学显微镜,对其组织进行了分析,用SEM观察了旋转电极粉末形貌,对室温及高温(550℃)拉伸性能及弹性模量等进行了测试分析.粉末TC11合金的组织和性能与同批次TC11锻棒材料进行了对比研究.利用特殊模具成形,开展了粉末TC11构件近净成形技术的研究,实现了整体大尺寸、带网格加强筋的薄壁粉末TC11合金航天飞行器舱体件近净成形,且未检测出内部缺陷.研究结果表明,粉末TC11合金具有与锻造材料相当的拉伸性能,而弹性模量更优,其金相组织均匀细致,形成了网篮组织,并有围绕其分布的等轴α.粉末TC11合金及合适的近净成形技术可在高性价比、高可靠性的轻质耐热航天飞行器构件制备中得到应用.

Microstructures and Properties and Forming Process ofPowder Metallurgy Heat Resistant Titanium Alloy

The prealloyed powder metallurgy (PM) process and HIP technology and PREP powders are used to
prepare full density PM TC11 (Ti-6. 5Al-3. 5Mo-1. 5Zr-0. 3Si) alloy, a kind of heat resistant titanium alloy. Heat
treatment is studied to optimize the microstructures and properties of the PM TC11 alloy. The microstructures are examined by optical microscope, and the morphologies of PREP powders are observed by SEM. Room temperature and
high temperature (550) tensile properties and elastic modulus of PM TC11 alloy are tested and discussed. The mi
crostructures and properties of the PM TC11 alloy are compared with those of the same batch forged rod. Nearnetshape processes are studied to fabricate PM TC11 parts. By using of special dies, a big dimension thin wall integrated
PM TC11 alloy spacecraft cabin with inner gridding stiffening ribs is nearnetshaped and no inner defect is detected.
The results show that the PM TC11 alloy has the same good tensile properties as forged material and plus perfect elas tic modulus. The microstructures of the PM TC11 alloy are fine and uniform and the typical ones are basketweave
structures surrounded by equiaxed  The PM TC11 alloy and suitable nearnetshape process can be used in the field of fabricating high performancetocost, high reliability, lightweight and heat resistant parts for spacecrafts.