热等静压对Ti-6Al-4V粉末冶金件组织和性能的影响

Effect of Hot Isostatic Press Process on Microstructure and Properties of PM Ti-6Al-4V Alloy Part

以Ti-6Al-4V合金棒材为原料,采用等离子旋转电极雾化法(PREP)制备出高品质球形钛粉,再通过热等静压近净成形工艺将粉末压制成块,并对Ti-6Al-4V合金块体的组织和性能进行研究。结果表明:Ti-6Al-4V合金粉末经热等静压后,组织主要由等轴α相+片条α相以及少量β相组成。升温升压速率较快时,粉末颗粒内部主要以片条状的α相为主,且同一束域内的α相彼此平行,规则排列成同一取向,颗粒边界处以等轴α相为主,其力学性能超过锻件;升温升压速率较慢时,冶金件组织发生明显粗化,力学性能介于锻件和铸件之间。

High quality spherical powder was prepared by plasma rotating electrode process（PREP） with Ti-6Al-4V bars as raw materials. The powders were pressed into blocks by the near net forming process of hot isostatic pressing, and the microstructure and properties of the titanium alloy blocks were studied. The results show that the microstructure of Ti-6Al-4V alloy block made by hot isostatic pressing is mainly composed of equiaxed α phase ＋ strip α phase and a small amount of β phase composition. When the heating rate is fast, mainly inside the particles is strip a phase, and the α phase in the same beam are paralleled to each other and arranged in the same orientation. The grain boundary is mainly equiaxed α phase, and the mechanical properties of Ti-6Al-4V alloy block made by hot isostatie pressing are better than the forgings. When the rising rates of heat and pressure are small, the microstructure gets coarsen obviously and the mechanical properties are between forgings and castings.