“节点修正”FVM-CA方法熔积凝固组织模拟

FVM-CA simulation of grain growth during solidification using‘node-based-correction'method

基于Nastac模型建立了一种优化的元胞捕捉机制,即"节点修正"法元胞自动机(CA)模型.较传统的CA模型能够简便有效地模拟任意主轴方向的柱状晶生长;将其与有限体积法(finite volume method,FVM)的宏观温度场模拟相结合,构建了一种改进的FVM-CA宏微观耦合计算方法.用该改进模型对碳钢电弧熔积组织演变过程进行了模拟,并探讨了熔积速度对熔池枝晶间距及生长方向的影响.试验结果证明了计算模型的合理性,该工作将为熔积增材成形金属零件的组织预测与控制提供科学基础.

Based on the Nastac model,a new capture mechanism,named node-based-correction method,was proposed to improve cellular automaton( CA) technique in the simulation of grain growth during solidification process with arbitrary crystallographic orientations. By coupling with the finite volume method( finite volume method,FVM),a FVM-CA simulation model was put forward and applied to the simulation of microstructure evolution of solidification during the arc deposition. The influences of the deposition rate on dendrite arm spacing and the growth direction were also discussed. Experiments were carried out to verify the validity of the numerical model. This research will lay the theoretical foundation of the prediction and control of microstructure in additive manufacturing.