对纯镍同轴送粉激光熔覆过程中宏观温度场与熔池底部微观组织生长进行了二维耦合模拟计算。首先利用标志变量法计算因粉末的加入而产生的边界动态改变,进行宏观温度场模拟,再取熔池底部一宏观单元进行网格细化,作为微观模拟区域,并通过插值计算获得微观模拟区域的初始温度条件,同时在计算中用宏观单元温度实时修正微观计算区域温度边界条件。在微观区域底部设置晶核,确定相场初始条件,并采用相场法进行微观区域的相场、温度场耦合计算,获得微观组织形貌。最后进行试验,在镍板基底上熔覆镍粉,模拟所得微观组织形貌与试验所得基本吻合,验证了模拟结果的正确性。 Two-dimensional coupling simulation of macroscopic temperature field and microstructure growth at the bottom of molten pool during laser cladding of pure nickel was carried out. First of all, the boundary variables are calculated by using the method of marker variable. The macroscopic temperature field is simulated. Then a macrocell at the bottom of the molten pool is used to refine the grid as a microscopic simulation area. The microscopic simulation area Of the initial temperature conditions, while in the calculation of the macro-cell temperature real-time correction of microscopic calculation of the regional temperature boundary conditions. The crystal nucleus is set at the bottom of the microscopic area, the initial conditions of the phase field are determined, and the phase field method and the phase field method are used to calculate the phase and temperature fields in the microscopic area to obtain the microstructure. Finally, the experiment was carried out, and the nickel powder was fused on the nickel plate substrate. The simulated microstructure was basically consistent with the experimental results, which verified the correctness of the simulation results.