【作者】 刘晴；

【导师】 张伟强；

【作者基本信息】 辽宁工程技术大学 ， 材料加工工程， 2002， 硕士

【摘要】 由于热电效应，在液态金属凝固期间，枝晶网络中出现电流，这样，当施加外加磁场时，电流与磁场相互作用产生洛仑兹力。对Al-4.5％Cu亚共晶和Al-33.2％Cu共晶两种合金进行了施加横向稳恒磁场的垂直定向凝固，实验结果表明，热电洛仑兹力驱动枝晶间的熔体流动，随着磁场强度的增大，流动加强，枝晶变粗，一次枝晶间距加大，并且随着凝固速率的提高，对流对枝晶的影响变小，而当磁场强度不变时，随凝固速度的提高，枝晶细化，一次枝晶间距变小，最后提出了固、液界面存在的热电流的数学模型。更多还原

【Abstract】 Because of thermoelectric effects, a local current density appears in dendritic network during the solidification of a liquid metallic alloy. Thus, when a magnetic field is applied, a Lorentz force is created. Two alloys of Al-4.5%Cu and Al-33.2%Cu are solidified directionally in the vertical configuration under a transverse magnetic field with the result that this force enforces fluid flow. The experimental results show that the stronger the flow is, the coarser the dendrite is and the bigger the arm spacing is. Moreover, as the solidification rate increases, the influence of the convection on the dendrite becomes weak. When the magnetic field strength is constant, the dendrite becomes thinner and the arm spacing smaller as the solidification rate becomes bigger. Finally, we establish the moddeling of current which lies in the interface of phase and fluid.更多还原