稳恒磁场条件下Al-Pb过偏晶合金凝固组织演变的模拟与分析

发布时间：2018-04-30 23:35

本文选题：偏晶合金 + 凝固组织　；参考：《金属热处理》2017年08期

【摘要】：采用欧拉-欧拉法建立了稳恒磁场条件下描述过偏晶Al-Pb合金难混溶区凝固过程的数学模型,对过偏晶合金在有无磁场条件下的宏观偏析运动进行了数值模拟,研究了两相温度场、速度场、体积分数等物性参数对合金凝固显微组织演化的影响。结果表明,随着冷却过程的进行,有磁场作用下的温度场仍保持环形中心对称分布,有效的抑制了由于重力条件下较强的对流作用使中心高温区上移;速度场在磁场条件下为中心对称分布,因部分重力被抵消,Marangoni力的作用逐渐显现,速度明显降低且方向斜向下指向对称轴,凝固组织宏观偏析得到了有效的改善;磁场条件限制了L2项液滴的扩散长大和Ostwald熟化,同时有效限制了L2项液滴体积分数的增加,从而更有利于L2项液滴的均匀分布。
[Abstract]:A mathematical model describing the solidification process of hypermonotectic Al-Pb alloy in the difficult miscible zone was established by using Euler-Euler method under the condition of steady magnetic field. The macroscopic segregation movement of the hypermonotectic alloy under the condition of magnetic field or not was numerically simulated. The effects of two phase temperature field, velocity field, volume fraction and other physical parameters on the microstructure evolution of alloy solidification were studied. The results show that, with the cooling process going on, the temperature field under the action of magnetic field still keeps the circular central symmetrical distribution, which effectively inhibits the upward movement of the central high temperature region due to the strong convection under the gravity condition. The velocity field is centrosymmetric distribution under the condition of magnetic field, because some gravity is counteracting the effect of Marangoni force, the velocity obviously decreases and the direction is inclined to the symmetry axis, and the macrosegregation of solidification microstructure is improved effectively. The magnetic field condition limits the diffusion and growth of L2 droplets and the ripening of Ostwald, and effectively limits the increase of droplet volume fraction of L2, which is more favorable to the uniform distribution of L2 droplets.
【作者单位】：沈阳建筑大学市政与环境工程学院;东北大学材料电磁过程研究教育部重点实验室;
【基金】：国家自然科学基金(51401133) 辽宁省科学技术基金(20141074) 辽宁省教育厅科学研究项目(L2014230) 沈阳建筑大学博士后基金(SJZUBSH201620)
【分类号】：TG146.21

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