激光熔化沉积2195铝锂合金微观组织演变及力学性能

采用激光熔化沉积技术对2195铝锂合金进行制备，通过单道以及搭接试验分析激光熔化沉积2195铝锂合金的最佳工艺参数，并利用光学显微镜(OM)等表征方法对其微观组织进行系统研究。结果表明，最佳沉积工艺参数为扫描功率1400 W,扫描速度480 mm/min,扫描间距1.6 mm。利用最佳工艺参数进行5层堆叠块体打印所得激光熔化沉积2195铝锂合金的微观组织中会出现沿晶界分布的析出相TB(Al₇Cu₄Li)相；激光熔化沉积2195铝锂合金经450℃固溶2 h后，合金中的第二相发生回溶；155℃时效32 h水冷后，合金中的不稳定过饱和固溶体Al₇Cu₄Li相会析出稳定的第二相，形成稳定时效态组织，硬度比固溶处理试样明显增加。

Microstructure evolution and mechanical properties of laser melting deposited 2195 aluminum-lithium alloy

2195 aluminum-lithium alloy was prepared by laser melting deposition (LMD) technology. The optimal process parameters of laser melting deposited 2195 Al-Li alloy were analyzed by single-channel and overlap-track experiments, and the microstructure of the alloy was systematically studied by optical microscope (OM) and other characterization methods. The results show that the optimum deposition process parameters are scanning power of 1400 W, scanning rate of 480 mm/min and scanning spacing of 1.6 mm, and precipitated Al₇Cu₄Li (TB) phase is found to distribute along grain boundary in the alloy 5-layer stacked blocks printed by the optimal process parameters, and then the precipitated phase gradually dissolves into the matrix after solution treatment at 450 ℃ for 2 h. After aging at 155 ℃ for 32 h and water cooling, stable second phase precipitates from unstable supraturated solid solution Al₇Cu₄Li and forming stable aging structure, so that the hardness of the aged specimen is significantly higher than that of the specimen solution treated.