采用激光熔覆技术在镁合金表面制备Al-Si共晶合金涂层，系统分析了激光功率对涂层凝固组织的影响规律。X射线研究结果表明，涂层主要相组成为Mg2Si、Mg17Al12 和密排六方的Mg2Al3，当激光功率为2.5 kW时由于稀释率较低，涂层中除了密排六方的Mg2Al3，还存在面心立方的Mg2Al3；当激光功率为4.0 kW时由于稀释率增加，出现α-Mg固溶体。结合扫描电镜和电子探针分析结果发现，激光功率为3.0 kW和3.5 kW涂层的凝固组织在Mg17Al12韧窝上分布的为Mg2Si枝晶组织和白色针状的Mg2Al3；当激光功率为2.5 kW时，在Mg17Al12韧窝上出现了花瓣状、面心立方的 Mg2Al3；借助透射电镜分析得到激光功率为4.0 kW时Mg2Si枝晶间的灰区基体上存在α-Mg固溶体。

Al-Si eutectic alloy coating was prepared on Mg alloy with laser cladding technology. Influence law of laser power on solidification structure of the coating was analyzed systematically. X-ray results showed that the coatings were mainly composed of Mg2Si, Mg17Al12 and Mg2Al3 (hcp) phases. However, the coating at the power of 2.5 kW had Mg2Al3 (fcc) besides Mg2Al3 (hcp) due to the low dilution rate. The coating at the power of 4.0 kW had α-Mg solid solution because of increasing of the dilution rate. Combined with the analysis of scanning electron microscope and electron microprobe, it was found that solidification structure of the coatings at the powers of 3.0 kW and 3.5 kW was characterized by Mg2Si dendrites, and needle-like Mg2Al3 (hcp) dispersing in the Mg17Al12 matrix, whereas the coating at the power of 2.5 kW was composed of the petal-like Mg2Al3 (fcc) as well as the needle-like Mg2Al3(hcp). The coating at the power of 4.0 kW appeared as α-Mg solid solution.