Fe-C合金凝固过程中的NbN析出模拟

Simulation of NbN precipitation during Fe⁃C alloy solidification

基于金属凝固和元胞自动机(CA)原理,提出了钢凝固过程柱状晶生长与夹杂物跨尺度的耦合模型及算法,并与Lipton-Glicksman-Kurz(LGK)解进行对比验证,还利用CA耦合模型模拟了Fe-C-Nb-N合金凝固过程中的柱状晶生长与NbN析出情况.结果表明:跨尺度CA耦合模型可以准确地模拟Fe-C-Nb-N体系柱状晶生长及夹杂物析出过程;在模拟柱状晶的生长过程中,当固相率达到0.53时,枝晶竞争生长明显并存在二次枝晶生长,当固相率达到0.71时,NbN开始析出;在NbN析出过程中,NbN呈点球状或不规则形貌,粒径为0.3~2.8μm,这与实验结果较为吻合.

Based on the principles of metal solidification and cellular automata(CA),a cross⁃scale coupling model and algorithm of the steel solidification process between columnar crystal growth and inclusions have been proposed and compared with the Lipton⁃Glicksman⁃Kurz(LGK)solution for verification.Besides,the columnar crystal growth and NbN precipitation during the solidification of Fe⁃C⁃Nb⁃N alloy have been simulated using the CA coupling model.The results show that the cross⁃scale CA coupling model can accurately simulate the columnar crystal growth and inclusion precipitation process of the Fe⁃C⁃Nb⁃N system.In the simulated columnar crystal growth process,the dendrite competition growth is obvious,and secondary dendrite growth exists when the solid phase ratio reaches 0.53,and NbN starts to precipitate when the solid phase ratio reaches 0.71.In the NbN precipitation process,NbN is in the shape of dotted spheres or irregular shapes and the particle size is 0.3~2.8μm,which is in good agreement with the experimental results.