【作者】 张宇博； 李廷举； 接金川； 卢一平； 王同敏；

【Author】 ZHANG Yubo;LI Tingju;JIE Jinchuan;LU Yiping;WANG Tongmin;School of materials science and engineering,Dalian university of technology;

【机构】 大连理工大学材料科学与工程学院；

【摘要】 立式水冷半连续铸造法是最常用的铝合金铸锭制备方法,为得到均匀细小的等轴晶组织,通常需要在半连铸过程中进行细化处理。本文中,超声场和中频磁场作为复合场同时作用于铝硅合金的半连续铸造过程中,制得直径160 mm、组织均匀细化的铝合金圆锭。超声场的空化作用在铝熔体内产生了很多有过冷度的微区,产生大量晶核。中频磁场增大了超声空化的作用区域,超声空化产生的初生晶核被超声声流和中频磁场引起的强制对流均匀地分散到半连续铸锭的熔体区。在晶粒长大过程中,复合场产生的强制对流会引起树枝晶在枝晶臂根部发生重熔或熔断,进一步达到细化晶粒的目的。复合场作用下,铸锭平均晶粒尺寸由l mm降为150 um,共晶硅的形貌由粗大针片状变为细小块状,铸锭抗拉强度增加16.9%,延伸率增加37.6%。更多还原

【Abstract】 Direct chill(DC) casting is widely used for the Al alloy production.In this study,the intermediate frequency electromagnetic(IFEM) field and power ultrasonic(US) field were applied during DC casting of Al-8%Si alloy.The effects of different physical fields on solidification micro structure and mechanical properties were studied.The results show that when the compound fields were applied,the EM field can increase the ultrasonic treated region,while the US field can enhance the refinement effect of IFEM field.Owing to the advantages of both IFEM and US fields,the micro structure is fine and uniform,leading to a remarkable enhancement of the mechanical properties.The mechanisms of interaction between the IFEM field and the US field were also discussed.更多还原