界面稳定性和形态的影响
(上海大学 材料科学与工程学院，上海 200072)
摘 要: 研究纵向稳恒强磁场在定向凝固Al-0.85%Cu(质量分数)合金平面晶−胞晶转变过程中，对界面失稳程度及胞晶形貌的影响。结果表明：随着磁场强度的增加，界面失稳程度先变小后变大，最后又变小；磁场强度为1 T时，界面失稳程度最大，胞晶间距先减小后增大；磁场强度为4 T时，胞晶间距达到最小值；同时，磁场也使得胞晶形貌变得不规则。采用磁阻尼效应和热电磁对流(TEMC)相互竞争的机制来解释相关现象。
关键词: Al-0.85%Cu；定向凝固；强磁场；界面稳定性；磁阻尼；热电磁对流
（School of Material Science and Engineering, Shanghai University, Shanghai 200072, China）
Abstract:The effect of steady high longitudinal magnetic field on the interface stability and cellular morphology of Al-0.85%Cu (mass fraction) alloys was studied. The results show that the degree of interface stability changes from high to low and then to high again, at last from high to low with increasing the magnetic field intensity. When the strength of the magnetic field is 1 T, the instable interface is the most obvious. With increasing the strength of the magnetic field, the cellular spacing decreases firstly, reaches its least value at 4 T magnetic field, and then increases. At the same time, the cellular morphology changes to irregular. The experimental phenomena were analyzed according to competition of convection damping effect and thermo-electromagnetic convection effect with the magnetic field.
Key words: Al-Cu alloy; directional solidification; high magnetic field; interface stability; magneto-hydrodynamic effect; thermoelectro-magnetic convection
