Mg表面激光熔覆Al-Si共晶合金的微观组织

Microstructure of Laser Cladding Al-Si Alloy Coating on Magnesium Alloy Surface

采用Al-Si共晶合金粉对Mg表面进行激光熔覆,使用扫描电镜和电子能谱对熔覆层的组织和构成进行了分析。结果表明,熔覆层主要由β(Mg17Al12)相、α(Mg)+β(Mg17Al12)共晶组织、α(Mg)固溶体、Mg2Si相组成,熔覆层和基体结合良好,未发现气孔和裂纹等缺陷存在。对熔覆层进行激光热处理后发现,熔覆层中粗大的Mg2Si相被熔断,呈细小块状分布于晶界,改善了熔覆层的性能。

The microstructure of laser cladding Al-Si alloy coating on the magnesium alloy surface was observed by SEM(scanning electron microscope) and EDS(energy dispersive spectrometer).The results reveal that the cladding coating is composed of Mg17Al12,α-Mg phase and Mg17Al12 eutectic phase,α-Mg solid solution phase and Mg2Si phase.The absence of defects,such as gas hole or crack,can be observed due to the desirable bonding between cladding coating and the matrix.The coarse Mg2Si phase in the laser heat treatment cladding coating is transformed into fine particle and uniformly distributed into the grain boundary,improving the performance of the cladding layer.