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研究了交流电场、直流磁场和二者复合产生的电磁振荡对A1-18%(质量分数)Si过共晶初晶Si相形貌的影响。结果表明:交流电场、直流磁场和电磁振荡都使合金初晶Si相的大小经历了一次细化过程,交流电场使Si原子有序偏聚团的尺寸和数目发生改变,增大形核率,细化初晶Si相;直流磁场通过电磁制动效应抑制了初晶Si相的形核与长大;电磁振荡细化作用是通过减弱合金的成分过冷和温度梯度从而增大过冷度实现的。三者相比,在电磁振荡的作用下初晶Si相更为细小。
The effects of alternating field, direct current magnetic field and electromagnetic oscillations on the Si phase morphology of A1-18% (mass fraction) Si hypereutectic primary crystal were studied. The results show that both the AC electric field, the DC magnetic field and the electromagnetic oscillation make the size of the primary Si phase of the alloy undergo a refining process. The size and number of the ordered segregation clusters of Si atoms change due to the alternating electric field, The primary Si phase is refined; the DC magnetic field inhibits the nucleation and growth of the primary Si phase through the electromagnetic braking effect; the electromagnetic oscillation thinning effect is achieved by reducing the undercooling and the temperature gradient of the alloy to thereby increase the undercooling of. Compared with the three, the primary Si phase is more fine under the action of electromagnetic oscillation.