AlCoCrFeNi high-entropy alloys coatings were prepared by laser powders directional energy deposition technology,and the influence of process parameters such as laser power,scanning rate and lap rate on the forming characteristics,microstructures and mechanical properties were investigated.The results show that with the increase of laser power,the melt width of single-pass coating increases,while the residual height and depth of melt firstly increase and then decrease.The melt width,residual height and depth of melt decrease to different degrees with the increase of scanning rate.The dilution phenomenon decreases with the increase of overlap rates.The coatings deposited by the overlap rates of 33％and 50％are dominated by equiaxed crystals,while the coating of 67％overlap rate is dominated by dendrites.The high G/R and the secondary annealing effect of the laser directed energy deposition result in the formation of sub-crystalline structures in multi-pass coatings.The multi-pass AlCoCrFeNi coatings significantly enhance the surface hardness of the Q235 substrate,with the hardness increasing from 167(HV)to more than 500(HV).The highest hardness of over 550(HV)is achieved for the 50％overlap rate coating.Moreover,the low dilution effect and unique microstructure of the multi-pass coating result in a significantly higher hardness than that of the single-pass coating.Balancing forming efficiency and low dilution rate,the laser power of 2 200 W,powder feeding rate of 10 mm/s and 50％overlap rate can be used as the optimal process parameters to prepare AlCoCrFeNi high-entropy alloys coatings.
关键词
激光粉末定向能量沉积/AlCoCrFeNi高熵合金/工艺参数/组织/力学性能
Key words
laser powders directional energy deposition/AlCoCrFeNi high-entropy alloys coatings/process parameters/microstructure/mechanical properties
维普
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