激光重熔对激光粉末床熔合制备Ti-6Al-4V合金热稳定性的影响机制研究  

Effect of Laser Remelting on Thermal Stability of Ti⁃6Al⁃4V Alloy Prepared by Laser Powder Bed Fusion

作　　者：詹宇星 杨扬[1] ZHAN Yuxing;YANG Yang(School of Materials Science and Engineering,Central South University,Changsha 410083,Hunan,China)

机构地区：[1]中南大学材料科学与工程学院,湖南长沙410083

出　　处：《矿冶工程》2024年第3期135-139,共5页Mining and Metallurgical Engineering

基　　金：国家自然科学基金(51871243,51574290)。

摘　　要：研究了激光重熔(LR)对激光粉末床熔合(LPBF)制备Ti-6Al-4V合金的组织性能和热稳定性的影响。结果表明,LR处理后,LRed-Ti-6Al-4V钛合金样品内α′相热稳定性显著提升,β-Ti相出现的温度点由500℃升至700℃。热处理后,LPBF-Ti-6Al-4V钛合金内晶粒持续生长,700℃以上出现明显的“短棒状”和“粗层片状”特征;而LRed-Ti-6Al-4V样品表层熔化区内晶粒仍维持等轴特征,700℃以上的熔化区和热影响区内呈现较为均匀细小的针状组织。两组样品的表面显微硬度值随温度升高而不断降低,并且分别在700℃和850℃显著下降,β-Ti晶粒的迅速粗化是引起硬度下降的主要原因。The effect of laser remelting(LR)on the microstructure property and thermal stability of Ti-6Al-4V alloy prepared by laser powder bed fusion(LPBF)was investigated.The results show that after LR treatment,the thermal stability of theα′phase within the LRed-Ti-6Al-4V titanium alloy samples is significantly improved,and the temperature at whichβ-Ti phase appears is up from 500℃to 700℃.After heat treatment,the grains in LPBF-Ti-6Al-4V titanium alloy grow continuously,and obviously appear to be“short bar-like”and“coarse lamellar”at the temperature above 700℃;while the grains in the melting zone of the surface layer of the LRed-Ti-6Al-4V sample are still maintain equiaxial,and the relatively uniform and fine needle-like microstructure are observed in the melting zone and heat affected zone above 700℃.The surface microhardness of those two groups of samples decreases with the increased temperature,especially significant at 700℃and 850℃respectively.It is found that the rapid coarsening ofβ-Ti grains is the main reason for the falling down of hardness.

关 键 词：增材制造 3D打印 激光粉末床熔合 激光重熔 Ti-6Al-4V 退火热处理 热稳定性 

分 类 号：TG156[金属学及工艺—热处理]