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研究了强静磁场对定向凝固Al-4.5Cu(质量分数,%)合金微观偏析的影响.结果表明,强磁场显著影响了凝固组织中非平衡第二相的形态和数量.无磁场时,粗大的第二相为网络状,连续分布于晶界上;施加磁场后,晶界上连续分布的第二相被打断,其面积分数随磁场强度的增加而减小.在磁场作用下,溶质原子的再分配行为发生改变,Cu溶质成分曲线降低,有效分配系数ke减小.上述现象主要是由于磁场在熔体中引发热电磁对流以及由热电磁对流驱动的二次流,在糊状区内产生搅拌,改变溶质传输行为.
The effect of strong static magnetic field on the microsegregation of Al-4.5Cu (mass fraction,%) alloy was investigated. The results show that the strong magnetic field significantly affects the morphology and number of non-equilibrium second phase in the solidified structure. Of the second phase of the network-like, continuous distribution in the grain boundary; the magnetic field, the grain boundary continuous distribution of the second phase is interrupted, the area fraction decreases with increasing magnetic field strength in the magnetic field, the solute The redistribution of atoms changes, the Cu solute composition curve decreases, the effective distribution coefficient ke decreases.The above phenomenon is mainly due to the magnetic field in the melt induced by the thermal electromagnetic convection and thermal electromagnetic convection-driven secondary flow in the mushy zone Produced within the mixing, changing solute transport behavior.