【摘要】 利用 5kWCO2 激光器对铸造铝硅合金表面进行两次激光辐照 ,先后将不同成分的预置合金粉末和基体材料一起熔化后迅速凝固 ,在其表面获得Cr/WC激光表面梯度层 ,并对它们的显微组织进行分析 ,发现在表面梯度层中存在大量的Al/Cr化合物Al9Cr4。在激光表面梯度层中自表及里显微硬度基本呈连续变化趋势 ,而单次激光表面合金化层与基体之间的显微硬度值有一突变。在基体和激光表面改性层的微动磨损试验中发现 ,激光改性后的表面抗微动磨损的能力增强 ,磨损机制不同于铝硅合金基体 ,而表现出较好的抗粘着损伤性能更多还原

【Abstract】 The Cr WC surface gradient layer on cast Al Si alloy was obtained by twi scanning the preplaced alloy coatings using a CO 2 continuous transvers flow laser beam with maximum power of 5kW.The microstructures of coatings were investigated.It is shown that there were more Al 9Cr 4 laths in laser surface gradient layer than in single laser surface alloying coating.The microhardness of laser surface gradient layer showed a gradual change from substrate to the surface.However the microhardness of single laser surface alloying coating was different distinctly from that of the substrate.Laser surface modified layers have better fretting wear resistance than that of the substrate,and there were different wear mechanism among them.Laser surface modified layers showed the better resistance of adhesion.更多还原