回火处理对激光熔覆颗粒增强镍基复合涂层组织及耐磨性的影响

采用优化的激光熔覆工艺在45#钢表面制备了质量良好的颗粒增强多道镍基复合Ni60CuMoW涂层。通过X射线衍射(XRD)、扫描电镜(SEM)和能谱(EDS)等表征手段研究了涂层的显微组织、颗粒相分布和结构特征。根据显微硬度和盘销式干摩擦磨损实验数据,比较了回火处理前后颗粒增强激光熔覆复合涂层的显微硬度分布和耐磨性能,并就热处理对磨损机制的影响进行了分析。结果表明,激光原位制备的颗粒增强镍基复合熔覆涂层经回火处理后,距结合界面0.3～0.8mm区域范围内析出的复合碳化物和硼化物硬质颗粒结构完整、尺寸分布均匀、密度大,与基体相界面呈牢固的冶金结合。回火处理前后涂层熔覆区的显微硬度较基体分别提高了4.9倍和5.8倍;耐磨性较基体分别提高了1.1倍和2.9倍。

Effect of Tempering on Microstructure and Wear Resistance of Laser Cladding Ni-Base Reinforced Particles Composite Coating

The particles reinforced multi-pass Ni60CuMoW composite coatings are fabricated by optimizing laser cladding process on the surface of 45# steel. The microstructure, particles phase distribution and structure features are characterized by X-ray diffractometer (XRD), scanning electron microscopy (SEM) and energy disperse spectroscopy (EDS). The micro hardness distribution and wear resistance of heat treatment composite coatings are measured by microscopic hardness tester and disc-pin dry friction and wear apparatus. The influence of heat treatment on wear mechanism is analyzed. The results show that the precipitation composite carbide and boride after tempering treatment have a good metallurgical bonding with 45# steel substrate in the range of 0.3~0.8 mm from interface. The composite coatings has the characteristics of integrality dimension distribution uniformry and high density. Compared with the 45# steel matrix, the average microhardness of the laser cladding Ni60CuMoW composite coatings before and after heat treatment increases by 4.9 times and 5.8 times, and the wear resistance increases by 1.1 times and 2.9 times, respectively.