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利用强剪切强对流的双向间歇电磁搅拌技术与低过热度浇注技术复合工艺作用合金熔体,制备了凝固显微组织形貌为晶粒尺寸细小、形态规则圆整的半固态A356-Ce合金铸锭,研究了在磁场作用时间恒定15s时铝合金熔体施加不同磁场频率、间歇时间对合金中初生α相晶粒尺寸和形貌演变方式的影响规律。结果表明,在合理的试验磁场频率和间歇时间范围内,随着磁场频率和间歇时间增加,初生相的尺寸逐渐细化、圆整度和分布均匀性增大。在磁场频率30Hz、间歇时间3s电磁搅拌工艺条件下半固态初生相的晶粒尺寸细化和球化程度达到最佳,组织中初生晶粒均匀分布,初生相的形貌由初始发达粗大的树枝晶向细小圆整的球状非枝晶转变,其平均等积圆直径处于各磁场频率和间歇时间作用下的最小值35.2μm;平均形状因子达到了峰值0.81。采用该复合工艺可制备出满足流变成形需要的优质的流变浆料。
The semi-solid A356-Ce alloy with fine grain size and regular shape was prepared by using the dual-batch intermittent electromagnetic stirring technique with strong shear and strong convection and the low superheat degree casting technique to make the alloy melt act as the solidification microstructure. The effects of different magnetic field frequency and intermittent time on the grain size and morphology evolution of the primary α phase in the alloy were studied when the magnetic field was applied for 15 s at a constant magnetic field. The results show that the size of the primary phase is gradually refined and the uniformity and uniformity of the primary phase increase with the increase of the magnetic field frequency and intermittent time within a reasonable range of test magnetic field frequency and intermittent time. Under the magnetic field frequency of 30 Hz and intermittent time of 3 s, the grain size refinement and spheroidization of the semi-solid primary phase reached the best. The primary grains were uniformly distributed in the microstructure. The morphology of the primary phase was mainly composed of coarsely- The average non-dendritic transformation of the grains toward the fine roundness shows that the average equivalent circle diameter is 35.2μm under the action of each magnetic field frequency and intermittent time, and the average shape factor reaches the peak value of 0.81. The use of the composite process can be prepared to meet the needs of rheological forming high-quality rheological slurry.