(1. 北京科技大学 材料科学与工程学院, 北京100083;
2. 内蒙古工业大学 材料科学与工程学院 ,
呼和浩特 010062)
摘 要: 在充分考虑半固态AlSi7Mg合金触变充型过程中压力和速度变化特征基础上,建立耦合半固态表观粘度的三维流场数学模型, 确定固定流量的入流边界条件和约束滑动型壁边界条件以及保持入流温度不变的初始条件, 并采用SOLA-VOF法对铝合金件的触变充型过程进行了模拟计算。 结果表明, 由于半固态表观粘度随剪切速率增大而下降, 造成局部浆料充型速度的复杂变化, 从而使半固态合金呈现剪切变稀的触变成形特点。 由于充型时间极短, 浆料在充型过程中降温小于1℃。 刹车泵体模拟计算结果展示了模拟与实际成形结果的一致性。
关键字: 充型模拟; 表观粘度; 半固态; 边界条件
(1. School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China;
2. School ofMaterials Science and Engineering,
InnerMongolia Polytechnic University,Huhehaote 010062, China)
Abstract:Based on the behavior characters of pressure and flow velocity during semi-solid AlSi7Mg slurry filling processes, a three dimensional model of slurry flow coupled with apparent viscosity was established. The filling simulation of the semi-solid forming process for semi-solid aluminum casting was investigated with the help of the SOLAVOF algorithm. And fixed volume of flow and sliding along wall were used for boundary conditions, slurry temperature was used for initiation condition. Results demonstrate that apparent viscosity decreases with the increase of shear rate, semi-solid alloy shows that shearing thinning thixotropy and its temperature differential is below 1℃ in the course of the filling.
Key words: filling simulation; apparent viscosity; semi-solid; boundary condition