(1. 東北大學(xué) 材料電磁過程研究教育部重點實驗室，沈陽 110004；
2. Division of Applied Process Metallurgy, Department of Materials Science and Engineering,
Royal Institute of Technology (KTH), Stockholm SE-10044, Sweden)
摘 要: 建立凝固過程中宏觀流動、傳熱、溶質(zhì)傳輸與微觀形核、生長過程雙向耦合數(shù)學(xué)模型，并針對Al-Si二元合金凝固過程進行二維元胞自動機−控制容積積分法(CA−FV)耦合模擬。模型反映了流場下晶體逆流生長特性，考慮了溫降導(dǎo)致的形核和生長以及形核和生長引起的固相分率變化對宏觀場的影響，能預(yù)測凝固過程中再輝和晶間偏析等現(xiàn)象，反映合金液流動對合金的溶質(zhì)分布以及凝固組織形貌的作用規(guī)律。與僅宏觀傳輸模擬結(jié)果和無流動影響的模擬結(jié)果進行了對比，驗證了耦合模型的優(yōu)越性。同時考察了鑄型尺寸對凝固組織形貌的影響。
關(guān)鍵字: Al-Si合金；凝固；晶體生長；宏觀偏析；元胞自動機−控制容積積分法
（1. Key Laboratory of Electromagnetic Processing of Materials, Ministry of Education,
Northeastern University, Shenyang 110004, China;
2. Division of Applied Process Metallurgy, Department of Materials Science and Engineering,
Royal Institute of Technology (KTH), Stockholm SE-10044, Sweden）
Abstract:A coupled cellular automaton−finite volume (CA−FV) model for macroscopic fluid flow, heat transfer, solute transport and microscopic nucleation and grain growth procedure was developed and applied in an Al-Si binary alloy solidification process. The model reflects the dendrite growth kinetics in the presence of fluid flow, the nucleation and growth in CA scale due to the increase of undercooling, and the feedback of solid fraction and temperature to FV nodes due to the nucleation and growth. The coupled CA−FV model can predict the recalescence and the intergranular segregation during alloy solidification process, which shows great advantages compared with the results by FV model and CA−FV model without fluid flow. The effects of fluid flow on the solute distribution and the solidification morphologies, as well as the influence of ingot size on the solidification structures, were discussed with the CA−FV model.
Key words: Al-Si alloy; solidification; grain growth; macrosegregation; cellular automaton−finite volume method
