Abstract: To reduce the pores and cracks in the microstructure of the TC4 titanium alloy formed by selective laser melting (SLM), and to enhance the comprehensive properties of the alloy, the post-treatment of the SLM-formed TC4 titanium alloy is carried out using the hot isostatic pressing technology. The microstructure, micro-area elemental composition and surface microhardness of the alloys formed without post-treatment and by traditional heat treatment are compared. The results show that the microstructure of the alloy treated by hot isostatic pressing technology is composed of α phase and β phase, the number of pores is significantly reduced, the cracks are repaired, presenting an approximately granular structure, new Ti-Al intermetallic compounds and new phase Ti0.66Al3V0.33 are formed, and the Vickers hardness of the sample is 455.60 HV. The Vickers hardness of the alloy samples is increased by 40.9% and 18.1% respectively compared with those without post-treatment and those with traditional heat treatment. This provides a guarantee for its stable application in the manufacturing of automotive parts and offers technical support for improving the quality of titanium alloy components used in automobiles.

Key words: SLM forming; heat treatment; hot isostatic; crack

摘要： 为减少选区激光熔化（SLM）成形 TC4 钛合金组织中的孔隙、裂纹，提升合金综合性 能，采用热等静压技术对 SLM 成形 TC4 钛合金进行后处理，并对比无后期处理和传统热处 理形成的合金微观结构、微区元素成分和表面显微硬度。结果表明，采用热等静压技术处理的 合金显微组织由 α 相和 β 相组成，孔隙数量明显减少，裂纹得以修复呈现近似颗粒状结构， 形成新的 Ti-Al 金属间化合物及新相 Ti0.66Al3V0.33，且试样维氏硬度为 455.60 HV，相比无后 期处理和传统热处理合金试样维氏硬度分别提高 40.9％和 18.1%。这为其在汽车零部件制造 中的稳定应用提供保障，为解决汽车用钛合金部件的质量提升提供技术支撑。

关键词: 选区激光熔化；热处理；热等静压；裂纹