Numerical Simulation of Columnar Crystal/Equiaxed Crystal Formation Model in a Convection Diffusion-multiphase Transformation System
HE Yin-hua1, WANG Fa-zhan1,2
1 College of Material and Mineral Resources, Xi'an University of Architecture and Technology, Xi'an 710055, China;
2 School of Mechanical and Electrical Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
Abstract：The horizontal rapid solidification of Fe-Bi-Mn free-cutting alloys were simulated by using diffusion-governed phase transformation kinetics. The three-dimensional solidification model for a convection diffusion-multiphase transformation system was built. Effects of alloys solidification on solid, liquid and gas phases flow diffusion transformation were considered. The Bi and MnS (free-cutting phases) of alloy columnar crystal/equiaxed crystal formation process were simulated. The results show that columnar crystal/equiaxed crystal formation model of Bi and MnS in alloy solidification is strongly influenced by convection diffusion and multiphase transformation terms; the large multiphase mass transfer rate and small enrichment degree of species easy to form columnar crystal where the convection diffusion term is positive; the small multiphase mass transfer rate and large enrichment degree of species appear at where the convection diffusion term is negative, the tip of columnar crystal breaking is caused by turbulence from convection diffusion and multiphase transformation when the species enriched to some degree, and which becomes the nucleation center of columnar crystal and the equiaxed crystal continues to grow and tends to be stable.
何银花, 王发展. 对流扩散-多相相变体系内柱状晶/等轴晶形成过程的数值模拟[J]. 材料工程, 2017, 45(6): 104-111.
HE Yin-hua, WANG Fa-zhan. Numerical Simulation of Columnar Crystal/Equiaxed Crystal Formation Model in a Convection Diffusion-multiphase Transformation System. Journal of Materials Engineering, 2017, 45(6): 104-111.
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2017, Vol. 45 
