相场法模拟316L不锈钢SLM过程中的微观组织演化

Microstructure Evolution Simulation during SLM Process by Phase Field Method

利用相场法模拟316L不锈钢在SLM成形过程中的微观组织演化。结果表明,在凝固过程中,微观组织演化分为平界面生长、平界面失稳、竞争生长和稳定生长4个阶段。在凝固过程中,溶质元素会在柱状晶之间和柱状晶尖端位置处聚集,导致溶质浓度值高于液相浓度和固相浓度,形成偏析。稳定生长阶段的微观组织呈现胞状晶形态,与试验观察微观组织一致。

The microstructure evolution of 316L stainless steel during SLM was simulated by using phase field method.The results indicate that during the solidification process,the microstructure evolution is divided into four stages:flat interface growth stage,flat interface destabilization stage,competitive growth stage and stable growth stage.The solute elements accumulate between the columnar crystals and at the tip of the columnar crystals,resulting in the higher solute concentration values than the liquid and solid phase concentrations,leading to segregation.During stable growth stage,the microstructure presents a cell-like crystal morphology,which is consistent with the experimentally observation.