AM50镁合金点焊接头的性能与组织分析

采用交流电阻点焊焊接了AM50镁合金板材，分析了点焊接头的力学性能、显微组织和断口形貌。结果表明：接头的抗剪强度随着电极压力、焊接电流以及焊接时间的增大均为先逐渐增大，待达到最大值后．又开始逐渐减小；板材表面清理状态对接头的质量有很大影响，未经过清理的试件接头强度较低；机械打磨的试件总体焊接质量较好；采用化学清理的焊件，接头质量稳定，强度随焊接电流增大逐渐提高。点焊接头的金相组织主要由等轴晶构成。断口分析显示延性断裂特征。

Mechanical Properties and Microstructure Analysis of AM50 Spot Welding Joints

AM50 plates was welded by AC spot welding. The mechanical properties, microstructure and fracture of the joints were investigated. The results show that shearing strength of the joints increases to a maximum value with the increase of electrode force,welding current as well as welding time,and then decreases regularly. Surface conditions of the plates have a significant influence, on quality of the joints. Un-cleaned samples have the iowest strength. Sanded samples have higher welding quality. Chemically processed samples have stable welding quality, and the strength of the joints increases with current rising. Microstructure of spot-welded joints are mainly composed of equiaxial grains. The characteristic of ductile fracture is observed by fracture analysis.