通过多层喷射沉积技术制备了大尺寸A356铝合金管坯, 采用光学显微镜、扫描电镜、X射线衍射仪和拉伸试验机等分析了管坯的组织特征及后续轧制和热处理对管坯组织与力学性能的影响。结果表明:喷射沉积A356铝合金管坯的组织细小, 但含有少量孔隙, 第二相主要为近球形共晶硅和短棒状富铁相;喷射沉积管坯为大量雾化熔滴粘结而成, 通过适当的轧制和热处理可以消除沉积坯中的孔隙和原始粉体界面强度弱等缺陷, 提高其力学性能。

Large size A356 aluminum alloy tube blank was prepared by multilayer spray deposition technology, and the microstructure characteristic and the effect of subsequent rolling and heat treatment on microstructure and mechanical properties were analyzed by using optical microscopy, SEM, X-ray diffractometer and tensile tester. The results show that the microstructure of A356 aluminum alloy tube blank prepared by spray deposition was tiny but contained a little pores, and the secondary phase was subsphaeroidal eutectic silicon and short-rod-like iron-rich phase. The spray deposition blank was preformed via large quantity of atomized droplets bonding. The pores in deposition blank and the weak boundary strength between original powders could be eliminated by proper rolling and heat treatment, and the mechanical properties were raised.