针对镁合金表面耐磨性差的问题，采用预置粉末法对AZ31B镁合金表面进行激光合金化Al-Cu粉末试验。通过扫描电子显微镜(SEM)、X射线衍射(XRD)仪、显微硬度计、摩擦磨损试验机对合金化涂层的相组成、微结构及性能进行了分析。结果表明，涂层与基体呈冶金结合、组织均匀致密、呈网状结构；涂层中除了有α-Mg、β-Al12Mg17外还含有CuMg2，且β-Al12Mg17含量远高于基体材料；涂层的显微硬度由50 HV提高到210~265 HV，为基体的4~5倍，相对耐磨性为2.5。

To improve wear resistance of the surface of magnesium alloy, laser alloying of Al-Cu powders coating on AZ31B magnesium alloy is achieved by the method of replaced-powder. The composition microstructure of the coating are analyzed by X-ray diffraction (XRD) and scanning electric microscope (SEM). Surface properties of the coating are evaluated using a micro-hardness tester and a abrasion tester condition at room temperature. The results show that the Al-Cu alloying layers are well bonded with the substrate; The XRD patterns show that the alloying coating is composed of α-Mg, β-Al12Mg17 and CuMg2, and the cortent of β-Al12Mg17 is higher than that of substract. The average micro-hardness of the surface layer is significantly improved from 50 HV to 210~265 HV, 4~5 times higher compared to the AZ31B substrate and the relative wear resistance is 2.5.