铝合金表面激光熔覆高硅涂层的组织与磨损性能

Microstructure and Wear Resistance of High Si Layer on Aluminum Alloys by Laser Cladding

用7kW横流CO2激光器在ZLl01铝合金表面激光熔覆高硅涂层。探索不同激光功率熔覆对涂层质量的影响,分析涂层的微观组织,测试涂层的硬度和磨损性能。结果表明:在优化工艺参数下制备出的激光熔覆高硅涂层组织致密、无气孔和裂纹,激光熔覆层中存在大量初晶Si、α-Al树枝晶和共晶组织。涂层与基体结合区处呈现典型的外延生长特征,形成了良好的冶金结合。熔覆层的横截面硬度在HV150～320之间,是基体的2～3倍,并显著提高了基体的耐磨性能。

Laser cladding of high Si layer on ZL101 alloy is performed by 7 kW COs laser. The effect of different power laser cladding parameters to layer is investigated. The analysis on the microstructure, the hardness and wear resistance of laser cladding layer shows that, the high Si layer is uniform, continuous and free of pores and cracks by optimized parameters. There are lots of primary Si, dendrite α-Al andα-Al ＋Si eutectic in the laser cladding layer. The interface between the layer and the substructure is epitaxial, with excellent bonding by the strong metallurgical interface. The hardness of laser cladding layer is about 2-3 times（in the range of HV 150~320）higher than that of the substrate, and wear resistance of sub- strate is greatly improved by the laser cladding.