铝合金表面脉冲电磁场对半连续铸造晶粒的细化

发布时间：2018-05-25 06:08

本文选题：晶粒细化 + 脉冲电磁场　；参考：《工程科学学报》2017年12期

【摘要】：采用一种新型熔体表面脉冲电磁技术对7A04铝合金半连续铸造凝固组织细化处理,分析脉冲电磁场对凝固组织及性能的影响.引入势能的观点,探讨脉冲磁能作用下的晶体形核动力学及初生晶核运动形式.结果表明,经表面脉冲电磁场处理后,凝固组织由晶粒尺寸粗大的玫瑰结构转变为细小且圆整的球状结构,铸锭心部及边部晶粒尺寸分别下降22.7%和14.2%,强度、塑性均有提高.动力学分析认为,脉冲电磁能降低体系形核所需的临界吉布斯自由能是增加形核率的重要原因,同时可导致初生α-Al运动的势能增加,促使初生α-Al颗粒优先到达稳定位置.
[Abstract]:A new melt surface pulsed electromagnetic technique was used to refine the solidified microstructure of 7A04 aluminum alloy in semicontinuous casting. The effect of pulsed electromagnetic field on solidification microstructure and properties was analyzed. From the point of view of potential energy, the crystal nuclear power theory and the motion form of primary crystal nucleus under the action of pulsed magnetic energy are discussed. The results show that the solidification microstructure changes from the rose structure with coarse grain size to the fine and round spherical structure after the treatment of surface pulsed electromagnetic field. The grain size in the center and edge of the ingot decreases by 22. 7% and 14. 2% respectively. The strength and plasticity of the solidified structure are improved. The kinetic analysis shows that the reduction of the critical Gibbs free energy required for nucleation is an important reason for increasing the nucleation rate. At the same time, the potential energy of the primary 伪 -Al motion increases, and the primary 伪 -Al particle preferentially reaches the stable position.
【作者单位】：内蒙古科技大学材料与冶金学院;
【基金】：国家自然科学基金资助项目(51044002) 科技部国际合作资助项目(2010DFB70630)
【分类号】：TG292

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