SLM制备Ti6Al4V合金表层组织的均质化及腐蚀行为研究  

Investigation of homogenization in surface microstructure and corrosion behavior of Ti6Al4V alloy prepared by SLM

作　　者：郑志军[1] 张文韬 ZHENG Zhijun;ZHANG Wentao(College of Mechanical and Automotive Engineering,South China University of Technology,Guangzhou 510641,China)

机构地区：[1]华南理工大学机械与汽车工程学院,广东广州510641

出　　处：《中南大学学报（自然科学版）》2024年第8期2991-3001,共11页Journal of Central South University:Science and Technology

基　　金：广东省自然科学基金资助项目(2021A1515010398)。

摘　　要：采用激光选区熔化(SLM)增材制造工艺制备致密度为97.5%的Ti6Al4V合金,并利用高能喷丸与退火处理复合工艺对垂直建造方向的XOY面及平行建造方向的XOZ面进行均质化处理,然后对原始打印件、喷丸处理以及喷丸+退火处理的3种状态的试样进行电化学性能测试。研究结果表明:经喷丸处理后,原始打印件XOY面和XOZ面的组织趋于均质化,同时组织明显细化;喷丸既不改变衍射峰的位置,也不产生新的衍射峰,但可使衍射峰宽化;对于喷丸后经不同温度退火处理的样品,随退火温度的升高,XOY面和XOZ面的晶粒逐渐长大,在780℃退火后,二者均可获得α+β双相组织。对于原始打印件,XOY面和XOZ面的电化学腐蚀行为存在明显的差异,其中,XOY面的腐蚀倾向更小,耐蚀性能更优。经喷丸+退火处理后,这种差异明显减小,同时耐蚀性能进一步提高,经综合考虑可得喷丸+780℃退火为最佳工艺。Ti6Al4V alloy with the densification of 97.5%was prepared by selective laser melting(SLM)process.The homogenization of the microstructures of XOY plane in the vertical construction direction and the XOZ plane in the parallel construction direction was carried out by high-energy shot peening and ensuing annealing.Finally,the electrochemical performances of the as-printed sample,the shot peening sample and the annealing sample after shot peening were measured.The results show that the microstructures of the XOY and XOZ plane in the as-printed sample are obviously refined and tend to be uniform after the shot peening.Shot peening does not change the position of the diffraction peak or produce a new diffraction peak,but can widen the diffraction peak.When the samples are annealed at different temperatures after shot peening,the grains in XOY and XOZ plane gradually grow with the increase of annealing temperature.The typical duplex microstructure includingαandβphase for Ti6Al4V alloy can be obtained after annealing at 780℃for both planes.The significant difference in the electrochemical corrosion behavior can be observed between the XOY plane and the XOZ plane in the as-printed sample,and the XOY plane has a smaller corrosion tendency and higher corrosion resistance than XOZ plane.This difference can be significantly reduced by the comprehensive treatment in annealing after shot peening,and the corrosion resistance is further improved.Annealing at 780℃after shot peening in general is the best process.

关 键 词：激光选区熔化 TI6AL4V合金 喷丸 组织各向异性 

分 类 号：TG172.5[金属学及工艺—金属表面处理]