中文摘要：

AZ91D 镁合金的团结的微观结构上的搏动的磁场的效果被调查。当搏动的磁场在 AZ91D 合金的团结被使用时，试验性的结果证明显著微结构精炼被完成。AZ91D 合金的当演员组微观结构的平均谷物尺寸被精制到 104 m。除谷物精炼以外，主要 -Mg 的形态学被改变从对插座树枝状，然后到有改变搏动的磁场的参数的球状的形状。搏动的磁场原因在团结期间融化传送对流，它做全部的温度融化一致，并且由磁性的压力在液体 / 固体接口前面生产一个 undercooling 地区，它使成核率增加并且禁止的大树突。另外，主要 -Mg 树突闯入好晶体，导致 AZ91D 合金的精制团结结构。在 melt 导致的焦耳热效果也加强谷物精炼效果和树突手臂的 spheroidization。

英文摘要：

The effects of pulsed magnetic field on the solidified microstructure of an AZ91D magnesium alloy were investigated. The experimental results show that the remarkable microstructural refinement is achieved when the pulsed magnetic field is applied in the solidification of AZ91D alloy. The average grain size of the as-cast microstructure of AZ91D alloy is refined to 104 μm. Besides the grain refinement, the morphology of the primary α-Mg is changed from dendritic to rosette, then to globular shape with changing the parameters of the pulsed magnetic field. The pulsed magnetic field causes melt convection during solidification, which makes the temperature of the whole melt homogenized, and produces an undercooling zone in front of the liquid/solid interface by the magnetic pressure, which makes the nucleation rate increased and big dendrites prohibited. In addition, primary α-Mg dendrites break into fine crystals, resulting in a refined solidification structure of the AZ91D alloy. The Joule heat effect induced in the melt also strengthens the grain refinement effect and spheroidization of dendrite arms.