扫描速度对硼化物金属陶瓷激光熔覆层组织和性能的影响

Effects of Scanning Velocity on Microstructure and Property of Laser Cladding Boride Cermet Coating

采用5 kW CO_2激光器在45钢表面熔覆制备MoB/CoCr金属陶瓷涂层,采用SEM、EDS和显微硬度计分别对在不同扫描速度下熔覆区的微观组织结构、化学成分分布和硬度进行测试。结果表明:熔覆区组织致密、无裂纹;200 mm/s扫描速度下熔覆区的组织呈现树枝晶—胞状树枝晶—胞状晶过渡,400 mm/s扫描速度时,熔覆区的组织呈现胞状树枝晶—胞状晶—平面晶过渡;熔覆层的主要化学成分均为Mo、Cr、Co和Fe;熔覆区的显微硬度明显提高,是45钢基体硬度的9倍以上。

MoB/CoCr cermet coating on 45 steel was laser cladded using 5 kW continuous wave CO_2 laser.The microstructure, energy spectrum and microhardness were tested by SEM,EDS and microhardness tester.The results show that the microstructure of cladding layer is dense;microstucture of cladding zone with 200 mm/s scanning velocity consists of dentrite crystal,cystiform dentrite crystal and cystiform crystal and microstucture of cladding zone with 400 mm/s scanning velocity consists of cystiform dentrite crystal, cystiform crystal and flat crystal.The main components of cladding layer are Mo,Cr,Co and Fe.The microhardness increased obviously and the average microhardness of layer was more than nine times to that of the 45 steel.