为改善AZ91D镁合金的表面性能, 采用预置粉末脉冲激光熔覆法在镁合金表面制备钴基合金涂层, 用扫描电镜(SEM)和能谱仪(EDS)分析熔覆层与基体结合界面特征、熔覆层成分。并结合Co-Cr相图、Co-W-C相图分析了熔覆层的组织形成过程, 对基体及熔覆层显微硬度和耐蚀性进行测试。结果表明:合金层与基体冶金结合,熔覆层无明显缺陷; 熔覆层硬度约为560 HV达到基体的9倍; 钴基合金层的耐蚀性能较高, 自腐蚀电位比AZ91D镁合金基体提高1.18 V, 腐蚀电流降低约5个数量级。

To improve the surface properties of magnesium alloy AZ91D, The purpose is to fabricate defect-free cladding layer on the surface of magnesium alloy AZ91D with pre-placed using YAG laser. The interface features and composition of cladding layer were studied through SEM and EDS. The forming process of cladding layer texture were studier through Co-Cr、Co-W-C phase diagram. The microhardness and corrosion resistance of substrate and cladding layer were texted. The results show that Co-based alloy cladding layer and the substrate achieve a good metallurgical bonding without obvious defects. The microhardness of Co-based alloy cladding layer is about 560 HV, more than 9 times to the substrate. Compared with AZ91D magnesium alloy, the corrosion potential of Co-based alloy layer is shifted by 1.18 V and the corrosion current is reduced to 5 order of magnitude.