(1. 江苏技术师范学院 机械工程学院，常州 213001；
2. 江苏大学 机械工程学院，镇江 212013)
摘 要: 采用 CO2 连续激光对 AM
关键字: AM50A镁合金；激光表面熔凝；细晶强化；固溶强化；弥散强化
（1. School of Mechanical Engineering, Jiangsu Teachers University of Technology, Changzhou 213001,China;
2. School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013,China）
Abstract:AM50A magnesium alloy was surface melted using a continuous wave CO2 laser, the microstructure properties and strengthening mechanism of the laser melted layer were analyzed. The results show that the grain of the laser surface melted layer is highly refined and the grain size decreases with increasing scanning speed. In the melted layer, the amount of element Al in solid solution increases, the amount of β-phase (Mg17Al12) decreases, and the distribution of β-phase becomes more uniform. The micro-hardness of the melted layer is improved to HV55−75 as compared to that of the substrate (about HV40). The wear volume of the laser surface melted sample is 35% of the untreated sample, the wear resistance of the laser surface melted layer is improved obviously. The main strengthening mechanism of the laser surface melted layer is grain refinement, the increase of element Al in solid solution and the dispersive precipitation of β-phase can also result in strengthening the melted layer.
Key words: AM50A magnesium alloy; laser surface melting; fine grain strengthening; solid solution strengthening; dispersion strengthening
