中文摘要：

为了提高覆层的硬度和耐磨性,在塑料模具钢P20表面预置非晶的纳米Al2O3,TiC,WC等陶瓷硬质颗粒的涂层,采用CO2激光器进行熔覆处理。对激光熔覆陶瓷复合层的显微组织结构进行了分析,并测试了其硬度和耐磨性。结果表明：通过高能量密度的激光处理,基体和熔覆层元素相互扩散与反应,其中的WC,Al2O3,FeSi成为熔覆层中的硬质相,显著提高了材料的硬度和耐磨性。磨损后熔覆层表面主要为细小的划痕,其磨损方式主要为磨粒磨损。

英文摘要：

In order to improve the micro-hardness and wear resistance of clad layer,the ceramic composite of amorphous nano Al2O3,WC,TiC is pre-placed on P20 base metal and then treated by a CO2 laser.The microstructure,micro-hardness and the wear resistance of the laser cladding composite layer were studied respectively.The results show that the elements of the base and clad layer diffuse and react each other,which lead to the formation of hard phases of WC,Al2O3 and FeSi in clad layer with great hardness and good wear resistance.The worn surface of the clad layer has the fine scratches on it,which appears a grain abrasion.