强迫对流下共晶组织生长的相场法模拟  

Phase-field simulation of eutectic growth during forced convection

作　　者：路阳[1,2] 冯小静[1] 冯力[1,2] 贾北北 

机构地区：[1]兰州理工大学材料科学与工程学院,甘肃兰州730050 [2]兰州理工大学省部共建有色金属先进加工与再利用国家重点实验室,甘肃兰州730050

出　　处：《兰州理工大学学报》2017年第2期19-24,共6页Journal of Lanzhou University of Technology

基　　金：国家自然科学基金(11504149;11364024)

摘　　要：基于三维共晶生长多相场模型与计算流体的LBM模型耦合,建立了相场-格子波尔兹曼模型(PF-LBM),以CBr4-C2Cl6合金为实例,模拟强迫对流下共晶微观组织的演化过程.结果表明:液态熔体流动会改变层片共晶的生长形貌,由垂直于固液界面对称、周期交替生长转变为倾斜于逆流方向生长,同时单个层片界面前沿出现由于间距调整而引起的异相形核现象.液体流动会使共晶组织生长速度加快;流动会改变共晶层片随层片间距增大而变化的生长模式,无流场时,共晶层片生长形貌变化模式为:稳态生长→低幅高对称性震荡→高幅低对称性震荡→棒状;强迫对流下,其层片生长变化模式为:稳态倾斜生长→层片前沿形核分叉→振荡态倾斜生长.Based on multi-phase-field model of three-dimensional eutectic growth and LBM model coupling in numeric fluid-dynamics, a phase-field-lattice Boltzmann （PF-LBM） model was established. Taking alloy CBr4-C2Cl6 as example, the evolution process of eutectic microstructure during forced convection was sim- ulate＆ The result showed that melted fluid flow would significantly change the lamellar euteetic growth morphology, transforming from symmetric and periodic alternating growth normal to the solid-liquid in- terface to growth inclined to the direction of the reverse flow. Meantime, ahead of single lameliar inter- face, heterogeneous nucleation phenomenon would appear due to the spacing adjustment. The liquid flow would accelerate the growth of eutectic structure and the flow would change the growth pattern of the eu- tectic lamella that it increases with the lamellar spacing, In the case of without flow field, the pattern of growth morphology of eutectic lamella would be stable growth→ low amplitude and high symmetry oscilla- tion--~high amplitude and low symmetry oscillation→rod pattern, and under the condition of forced con- vection, its growth pattern would be stable and tilt growth→ lamellar branching and merging→oscillate tilt growth.

关 键 词：PF-LBM 等温凝固 强迫对流 共晶生长 

分 类 号：TG248[金属学及工艺—铸造]