电磁组合场对镁合金凝固组织的影响

研究了不同电磁组合场对AZ61镁合金凝固组织的影响.结果表明,在静磁场作用下,镁合金的凝固组织为等轴晶,晶界上的结晶相成网状分布;在静磁场与工频交流电组合场作用下,其凝固组织与只施加静磁场时类似,基本为等轴晶,但由于交流电的施加晶粒明显得到细化,晶界上结晶相的网状结构也变得细小;而在镁合金凝固过程中同时施加静磁场和直流电流组合场时,由于组合场产生的熔体内部的定向力作用的结果,凝固组织主要为蔷薇状晶粒,组织得到明显的净化,其晶界上结晶相的网状结构彻底消失,以不连续的薄条状和点状形态分布.

Effect of Electric-Magnetic Field on Solidification Microstructure of Magnesium Alloys

Solidification microstructure of AZ61 magnesium alloys with different electric-magnetic fields was studied. It was found that solidification microstructure of magnesium alloys were equiaxed grains and the Mg-Al-Zn compound phases appeared as meshes on grains boundaries under magnetostatic filed. Solidified under the magnetostatic-power current field, the microstructure was mainly consisted of equiaxed grains similar to that under the magnetostatic field. But the grains were refined obviously and the mesh structure of compound phases became fine due to the applied power current; while in the solidification process of Mg alloys under the magnetostatic-direct current field, the solidification microstructure was mainly rosette grain and purified significantly; the mesh structure of the compound phases disappeared entirely and they were distributed as discontinuous ribbons and spots; they were the results of the directional force inside melts caused by the combination fields.