中文摘要：

通过研究不同外场作用下镁合金AZ61的凝固组织，发现在静磁场单独作用时的晶界主要由镁基体和连续的网状化合物组成，在静磁场与交流电组合外场下的晶界主要由镁基体和网状及点状Mg-Al-zn化合物组成，而在静磁场与直流电组合外场下晶界上的连续网状化合物彻底消失，化合物以不连续的薄片形态分布于镁基体上．相对于单一静磁场作用时，静磁场与电流共同作用时提高了镁合金晶内溶质含量，降低了晶界上的溶质含量.

英文摘要：

Through studying the microstructure of AZ61 alloy solidified in different external fields, it is found that when solidified in single magnetostatic field , the grain boundaries were composed of matrix Mg and meshy Mg-A1-Zn compounds . When solidified in the field composed of magnetostatic field and alternating current , the grain boundaries were composed of matrix Mg and Mg- A1-Zn compounds which existed as isolated spots as well as a certain amount in the meshy state. But when solidified in the field composed of magnetostatic field and direct current, the mesh disappeared and together with matrix Mg a little Mg-A1-Zn compound appeared as discontinuous flakes. Compared with single magnetostatic field, solidification in magnetostatic field and currenmakes the solute content in grains to increase and the solute content in grain boundaries to decrease.