电阻点焊熔核微观组织模拟
Microstructure simulation of resistance spot welding nugget
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摘要: 基于有限差分思想建立了电阻点焊的三维宏观传热模型,并在此模型基础上通过进一步细化网格差分得到枝晶形核和生长所需的温度信息.基于元胞自动机方法建立枝晶形核和生长的微观模型,将已建立的宏观温度场模型和微观元胞自动机模型互相耦合起来,建立了电阻点焊熔核微观组织模拟的宏微观耦合模型.利用耦合模型模拟了5754铝合金电阻点焊一定参数下熔核的微观组织形成过程,所得的模拟结果为"柱状+等轴"晶组织,与试验结果吻合较好.Abstract: We established a three-dimensional macro heat transfer model through the method of finite difference, and then the information of the temperature field which is needed in the calculation of nucleation and growth of dendrite was obtained by further refining the mesh. The micro model of nucleation and growth was established based on the cellular automaton method. The nugget microstructure simulation was set up by coupling the macro temperature field model with the micro cellular automaton model. It is successful to simulate the formation of resistance spot welding microstructure by using this model, and the simulation results were verified by means of real time image. The numerical simulation results indicated that the nuggets of 5754 aluminum alloy were made up of columnar-equiaxed crystals, which were consistent with the experimental results.