为提高镁合金表面硬度和耐磨性,采用激光熔覆技术在镁合金表面制备Al-Si共晶合金涂层,系统分析了涂层的硬度和耐磨性变化特征。研究结果表明,涂层主要相组成为Mg2Si、Mg17Al12和Mg2Al3,显微组织为方向紊乱的树枝晶。涂层硬度高达350～450 HK,较原始镁合金的硬度(80 HK)提高340%～462%。涂层的摩擦系数与原始镁合金相同,均为0.3左右。由磨痕宽度换算成磨损体积得到涂层磨损体积为4×10-3 mm3,而原始镁合金磨损体积为67×10-3 mm3,与原始镁合金相比,涂层的耐磨性提高74%～92%。

Al-Si eutectic alloy coating was prepared on Mg alloy with laser cladding technology in order to improve the hardness and wear resistance of Mg alloy. The variation characteristic of hardness and wear resistance of the coating was analyzed systematically. The results showed that the coating was composed of Mg2Si, Mg17Al12and Mg2Al3 phases. The microstructure of the coating was the direction disorder dendrite. Hardness of the coating (350～450 HK) was improved 340%～462% as compared with that of as-received Mg alloy (80 HK). Friction coefficient of the coating and as-received Mg alloy was both 0.3. The wear volume of the coating (4×10-3mm3) was improved 74%～92% as compared with that of as-received Mg alloy (67×10-3mm3).