温度场监控下高功率半导体激光熔敷钴基合金涂层

采用3.5 kW半导体激光器在42CrMo4表面熔覆了钴基合金(Stellite 6)涂层,利用光学显微镜和显微硬度仪表征了涂层的微观组织和硬度分布,研究了监控熔覆过程中的熔池温度场对涂层的微观结构和显微硬度的影响.结果表明:基于熔池温度场拍摄并调整激光器输出功率的熔池大小闭环监控的工艺可实现对钴基合金涂层的稀释率以及结构与性能的调控:当送粉量为22.6 g/min、熔覆速率为1 m/min时,基于熔池温度场监控的工艺调整实现了近零稀释率的钴基合金涂层的熔覆,所需激光功率仅为1.5 kW;涂层与基体形成良好的冶金结合,组织致密,主要由平面晶、胞状晶、树枝晶和等轴晶构成,晶粒细小,显微硬度达到HV600.

High power diode laser cladding of Co-based alloy coating under temperature field control

Co-based alloy (Stellite 6) coatings were prepared on 42CrMo4 plates by using high power diode laser with the nominal output power of 3.5 kW.Optical microscope and micro-hardness tester were used to characterize the morphology,microstructure and the hardness profile of the coatings.The effects of controlling the temperature field of the molten pool on microstructures and micro-hardness of these coatings were investigated.The results reveal that the dilution rate,morphology,microstructure and property of the Co-based alloy coatings can be adjusted under the closed-loop control of molten pool temperate.On the condition that the powder feed rate of 22.6 g/min,laser beam scanning rate of 1 m/min,and laser power of 1.5 kW.a Co-based alloy coating with nearly non-dilution was obtained by properly employing process parameters based on this adjustment approach.The Co-based alloy consisted of planar grains,cellular grains,free dendrite grains and equiaxed grains from the interface to the top of the coating.It had good metallurgical bond with the substrate and its micro-hardness was up to HV600.