铝合金表面激光熔覆SiC颗粒增强复合耐磨涂层研究

采用激光熔覆技术在铝合金表面制备SiC颗粒增强的N i基合金复合涂层,其中SiC粉末采用预置和同步送粉两种方法。试验结果表明,在激光功率P=2kW、光斑直径d=3m m、扫描速度v=3m m s/工艺条件下,预置SiC粉末厚度1m m或送粉量m p=8gm/in,可以获得表面平、无裂和界面结合较好的熔覆层。测试了熔覆层的硬度和滑动摩擦磨损性能,分析了熔覆层的硬化机理,熔覆层中存在颗粒强化、固溶强化等强化作用,熔覆层的显微硬度达到900～1100H V,其耐磨性能比铝合金显著提高。

Study on Laser Cladding of Wear-Resistant SiC Particle Reinforced Composite Layer on Aluminium Alloy Surface

SiC particle reinforced Ni matrix composite layer was fabricated on the surface of aluminium alloy substrate by laser cladding technology where two modes of powder feeding,i.e.,precoating or synchronous feeding, were employed respectively.The experimental results indicated that,an even clad layer free of cracks and better binding with the substrate can be attained under the processing conditions of laser power P=2 kW;scanning velocity v=3 mm/s;beam diameter d=3 ram;SiC powder precoating thickness is 1 mm or powder feeding rate mp=8 g/min.The microhardness and sliding tribological properties of the clad layer were measured,as well as its strengthening mechanisms were analyzed. The results showed that,owing to the particles strengthening and solution strengthening, the microhardness of laser clad layer can be up to 900-1 100 HV,while a remarkable increase in wear resistance is obtained comparing with aluminium alloy.