不同磁场作用下ZK60镁合金的凝固组织

实验研究了镁合金ZK60在无磁场、低频交变电磁场和静磁场作用条件下凝固的微观组织形貌及合金元素的分布;此外还数值模拟了凝固过程中的磁场分布·实验结果表明,在镁合金的凝固过程中施加低频交变电磁场或静态磁场都能有效细化晶粒及影响合金元素在晶内和晶界上的分布,并且晶界上的网状共晶组织变得不连续;在相同电源电压的条件下,静磁场细化晶粒的效果明显优于低频磁场,在静磁场条件下,聚集在晶界上的共晶化合物显著减少,在晶内和晶界附近存在大量弥散的近似球状化合物质点,这有利于提高镁合金的综合性能·

Microstructure of Mg Alloy ZK60 in Different Magnetic Fields

The microstructure and distribution of alloying elements of magnesium alloy ZK60 were studied experimentally and comparatively, which was solidified under the actions of no magnetic field, low-frequency a.c. electromagnetic field and magnetostatic field, separately. In addition, the distributions of different electromagnetic fields in the solidification process were simulated numerically. The results showed that applying either low-frequency a.c. electromagnetic field or magnetostatic field on the alloy in its solidification process can refine effectively grains and affect the distribution of alloying elements within the grain and on grain boundaries, with discontinuous eutectic net structure found on grain boundaries. The effect of grain refining by magnetostatic field is evidently better than that by low-frequency a.c. electromagnetic field. Furthermore, the eutectic compounds aggregated on grain boundaries are reduced greatly, and lots of dispersive sphere-like particles of compounds are found within grains and in the vicinity of grain boundaries, which are beneficial to improving the overall properties of the magnesium alloy.