AZ33M镁合金激光熔覆Al-Si涂层的组织与性能

利用激光熔覆技术在AZ33M镁合金表面制备了Al-Si涂层,通过采用腐蚀电化学测试结合X射线衍射仪(XRD)、扫描电镜(SEM)及显微硬度计等对熔覆层微观组织和性能进行了表征。结果表明,熔覆层主要由Mg和Mg₁₇Al₁₂、Mg₂Si及Mg₂Al₃相组成。熔覆层显微组织由柱状树枝晶和方向各异的树枝晶组成。由于第二相强化和细晶强化等原因,制备的Al-Si涂层相比镁合金基体具有更高的硬度。熔覆层的自腐蚀电位相比基体提高了约400 mV,自腐蚀电流降低了一个数量级,熔覆层的耐蚀性明显优于基体镁合金。

Microstructure and properties of laser clad Al-Si coating on AZ33M magnesium alloy

Al-Si coating was prepared on the surface of AZ33M magnesium alloy by laser cladding technology. The microstructure and properties of the clad layer were characterized through corrosion electrochemical method test combined with X-ray diffractometer (XRD), scanning electron microscope (SEM), microhardness tester, etc.. The results show that the clad layer is mainly composed of Mg matrix, Mg₁₇Al₁₂, Mg₂Si, and Mg₂Al₃ phases. The microstructure is composed of columnar dendrites and dendrites with different directions. Due to second phase strengthening and fine-grain strengthening, the prepared Al-Si coating has higher hardness compared with magnesium alloy matrix. Compared with the matrix, the self-corrosion potential of the clad layer is increased by 400 mV, the self-corrosion current is reduced by an order of magnitude, and the corrosion resistance of the clad layer is significantly better than that of the magnesium alloy matrix.