激光熔覆参数对Ni204合金涂层形貌及组织的影响

The Influence of Laser Cladding Parameters on Morphology and Microstructure of Ni204 Alloy Cladding Layer

利用激光熔覆技术对Ni204进行了单道正交试验,采用激光共聚焦显微镜测量熔道几何尺寸及组织,采用方差分析不同工艺参数对试样形貌以及组织的影响。结果表明,功率对熔宽、熔深影响最显著;扫描速度对熔高、宽高比(W/H)、润湿角影响最显著;能量密度过小时,Ni204合金粉末在基体上没有形成熔池,熔池边界处组织为柱状晶,熔池内组织生长时间短且不易再结晶,熔池内为枝晶。通过分析,最优工艺参数组为L_p=750 W,P_(fr)=0.8 r/min,S_s=480 mm/min与L_p=900 W,P_(fr)=1 r/min,S_s=480 mm/min。可以在保证横向、纵向搭接的同时又不降低熔覆效率。

The single pass orthogonal test was carried out for Ni204 by laser cladding technology.The geometry size and microstructure of the clad track were measured by laser confocal microscopy.The effects of different process parameters on the morphology and microstructure of the samples were analyzed by variance analysis.The results show that the power has the most significant influence on the melting width and depth.The influence of scanning speed on the melting height,the ratio of width and height and wetting angle was most significant.When the energy density is too small,the Ni204 alloy powder does not generate a molten pool on the substrate.The microstructure at the boundary of the molten pool is columnar crystal.In the molten pool,the grain growth time is short and recrystallization is not easy,and the molten pool is dendritic.Through analysis,the optimal process parameter groups were Lp=750 W,Pfr=0.8 r/min,Ss=480 mm/min and Lp=900 W,Pfr=1 r/min,Ss=480 mm/min which can ensure the horizontal and vertical overlap without reducing the cladding efficiency.