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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。
The MoB / CoCr cermet coatings were prepared by laser cladding on a 45 steel surface with a 5 kW CO 2 laser. The microstructure, chemical composition distribution and hardness of the cladding were investigated by SEM, EDS and microhardness tester respectively. test. The results show that the microstructure of the cladding zone is compact and free of cracks. The microstructure of the cladding zone appears dendritic-dendritic-cellular transition at 200 mm / s scanning speed. At 400 mm / s scanning speed, Cell dendrites - cellular crystal - plane crystal transition; the main chemical composition of the cladding layer is Mo, Cr, Co and Fe; cladding microhardness significantly increased, 45 times the hardness of 45 steel substrate.