【作者】 黄立国；

【导师】 张伟强；

【作者基本信息】 辽宁工程技术大学 ， 材料学， 2005， 硕士

【摘要】 本文研究了连续电场(包括直流电场和交流电场两种形式)分别对Al-Cu、Al-Si共晶合金凝固组织的影响,探讨了电场改变Al-Cu、Al-Si合金凝固行为的机理。实验及理论研究表明:直流电场和交流电场都在一定程度上降低了合金的凝固点,相应的提高了过冷度,增大了合金的凝固形核率,从而Al-Si合金组织中共晶Si质点增加,Al-Cu合金组织中共晶晶粒尺寸减小、数量增加;电场细化Al-Si合金的凝固组织,共晶Si由原来的针片状演化成细小的颗粒状,直流电场较交流电场的作用更明显;电场细化了共晶合金的两相间距,对于Al-Cu合金来说,电流密度较大时,直流电场作用下的共晶片层变的紊乱,交流电场作用下则出现了退化共晶组织。更多还原

【Abstract】 The effect of electric field(direct current electric field and alternate current electric field) on the solidified structure of Al-Cu and Al-Si eutectic alloys is studied, mechanism of the solidifying behavior of Al-Cu and Al-Si eutectic alloys under electric field is discussed. The study shows: the solidifying point of the alloy is decreased and the degree of supercooling is improved at some extent due to the effect of direct and alternate current electric field, the nucleating rate of the alloy is increased and eutectic Si points increased in Al-Si alloy and the size of eutectic particles in Al-Cu decreased but quantities increased. The solidifying structure of Al-Si alloy is refined by the electric field, the eutectic Si change from flake-like structures to fine particles, the effect of direct electric field is more than altenative electric field, the clearance of the two phases is decreased by electric field. Due to the Al-Cu alloys, the eutectic lamellars are disturbed by the direct electric field and the degenerate eutectic structures appear due to the effect of altenative electric fields.更多还原