(1. 太原理工大学 材料科学与工程学院，太原 030024；
2. 太原理工大学 新材料界面科学与工程教育部重点实验室，太原 030024)
摘 要: 针对镁合金表面耐磨性和耐蚀性差的问题，利用横流CO2激光器在AZ31B镁合金表面激光熔覆Cu-Ni合金层，并利用光学显微镜(OM)、扫描电镜(SEM)和能谱分析仪(EDS)分析熔覆层与基体的结合界面特征以及显微组织和成分分布情况，测试合金层的显微硬度和耐蚀性。结果表明：合金层与基体结合良好，缺陷较少，但局部存在不均匀的Cu-Ni富集区，且在其边缘区域的枝晶间均匀分布着1~1.5 µm的十字状Laves相；合金层的硬度分布比较均匀，约为75HV0.05，明显高于基体的显微硬度45HV0.05；Cu-Ni合金层比AZ31B镁合金基体的腐蚀电位正移317 mV，腐蚀电流降低78 mA/cm2，耐蚀性也得到较大改善。
关键字: AZ31B镁合金；Cu-Ni合金层；激光熔覆；耐磨性；耐蚀性
（1. College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China;
2. Key Laboratory of Interface Science and Engineering in Advanced Materials of Ministry of Education,
Taiyuan University of Technology, Taiyuan 030024, China）
Abstract:To improve the wear resistance and corrosion resistance of the surface of magnesium alloy, the laser alloying experiment was carried out on the AZ31B magnesium alloy with pre-placed Cu-Ni powder using transverse flow CO2 laser. The microstructures, interface features and composition distribution of laser cladding layer were studied through OM, SEM and EDS. The results show that the Cu-Ni cladding layer and the substrate achieve a good metallurgical bonding without obvious defects. But there is uneven local Cu-Ni-rich region, and cross-like Laves phases with size of 1−1.5 μm evenly distribute between dendrites and in their edge regions. The microhardness of Cu-Ni cladding layer is more evenly distributed, about 75HV0.05, significantly higher than the matrix hardness (45HV0.05). Compared with AZ31B magnesium alloy, the corrosion potential of Cu-Ni alloy layer is shifted by 317 mV and corrosion current is reduced by 78 mA/cm2.
Key words: AZ31B magnesium alloy; Cu-Ni alloy layer; laser cladding; wear resistance; corrosion resistance
