镁合金表面激光熔覆Al-Si基纳米SiC复合涂层的组织及性能

纳米材料由于其结构的特殊性,具有一般材料难以获得的优异性能,为了将纳米材料的优异性能应用到镁合金表面改性当中,利用横流CO₂激光器在AZ31B镁合金基体上制备了Al-Si合金粉末+5%纳米SiC粉末复合涂层,采用光学显微镜、扫描电子显微镜观察了熔覆层的显微组织并分析了微区成分分布情况,激光熔覆层与基体结合良好,熔覆层的显微组织具有明显的结构特征,出现了大量的十字架结构。X射线衍射结果表明,激光熔覆层的组成相主要为Mg₂Si、Mg₂C₃、Mg₁₇Al₁₂、A_l3.21Si_0.47等。利用显微硬度仪进行了硬度测试,由于在激光熔覆过程中新形成的化合物起到了强化作用,熔覆层的最高显微硬度可达216 HV0.2,是基体的3倍多。

Microstructure and Property of Magnesium Alloy by Laser Cladding with Al-Si-Based Nano-SiC Composite Coating

Because of i ts unique structure, Nano -materials witha better access to the excellent material properties, which wasapplied to the surface modification of magnesium alloys, Al-Si alloy powder垣5%nano-SiC composite coating was formed on AZ31B magnesium alloy substrate by a cross flow CO2 laser, the microstructure and phase analyses of cladding layer was studied by opticalmicroscopy, scanning electron microscopy and X-ray diffraction, microhardness was also tested. The microstructure of the claddinglayer hasa clear structure, there has been a large number of cross structure, the XRD pattern shows that the coating is composed ofMg2Si, Mg2C3, Mg17Al12, Al3.21Si0.47, etc, as the new compounds formed in the laser cladding process, the maximum hardness of thecladding layer up to 216 HV0.2, more than three times of the matrix.