基于三相模型的Al-4Cu合金半连铸圆锭的宏观偏析数值模拟  

Numerical Simulation for Macrosegregation of Al-4Cu Alloy Ingot During Direct Chill Casting Based on Three-Phase Model

作　　者：罗海军[1] 介万奇[1] 郑永健 吴孟怀 高志明[1] Luo Haijunl, Jie Wanqi1, Zheng Yongjian2, Wu Menghuai2, Gao Zhiming1(1. State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi＇an 710072, China） （2. Universitaet of Leoben, A-8700 Leoben, Austria)

机构地区：[1]西北工业大学凝固技术国家重点实验室,陕西西安710072 [2]University of Leoben,A一8700 Leoben,Austria

出　　处：《稀有金属材料与工程》2018年第10期3030-3037,共8页Rare Metal Materials and Engineering

基　　金：国家重点基础研究发展计划(2016YFF0101301)

摘　　要：采用基于Eulerian-Eulerian方法的等轴晶、柱状晶以及熔体三相完全混合的凝固模型计算了半连铸Al-4Cu铝合金圆锭的宏观偏析。在热溶质对流的基础上,模型考虑了等轴晶的移动,柱状晶对浮游等轴晶的捕获,以及等轴晶和柱状晶的相互竞争生长行为。模拟结果表明,铸锭出现了明显的底部锥形负偏析区(CET转变区域),铸锭中心正偏析带,毗邻中心的负偏析区,以及铸锭1/2半径处正偏析带,总的偏析形态呈现W型,与铸锭实际情况基本一致。此外,铸造速度相较于浇注温度对铸锭宏观偏析的影响更大。A mixed three-phase solidification model based on the Eulerian-Eulerian approach and the volume average method for macrosegregation were applied to predict the segregation in Al-4 Cu alloy ingot during direct chill casting（DC）. In addition to the thermosolutal buoyancy flow, we considered the movement of equiaxed crystals, the capture of equiaxed crystals by growing columnar crystals and the interaction and impingement between columnar and equiaxed crystals in the model. The results show that a conical zone of negative segregation is obviously observed at the bottom of the ingot. Negative segregation is also observed adjacent to the center, whereas positive segregation is obtained in the center and middle of the radius. This W-type segregation profile is in agreement with the measured experimental data obtained from literatures. At the same time, the influence of pouring temperature and casting speed on macrosegregation were also studied. It indicates that casting speed has a greater effect on segregation than the pouring temperature.

关 键 词：三相模型 宏观偏析 数值模拟 圆锭 半连铸 

分 类 号：TG146.21[一般工业技术—材料科学与工程]