【作者】 陈东风；

【导师】 曹志强；

【作者基本信息】 大连理工大学 ， 材料加工工程， 2006， 硕士

【摘要】 作为一种新兴的净化技术，电磁净化具有清洁、高效的特点，近年来一直是研究的热点之一，已经逐渐发展成为具有广阔应用前景的新型金属熔体净化技术。本实验采用外加高频磁场的方法，利用富铁相颗粒与熔体导电性的差异，使微米级的富铁相在电磁挤压力的作用下从熔体去除，从而实现了熔体净化的目的。 本文从电磁场的基本原理出发，根据金属熔体内部电磁体积力的数学式，分析了固相颗粒在金属熔体中的运动速度计算模型，并对影响电磁分离效率的各项参数进行了分析，包括磁场强度、作用时间、管径大小等因素。采用Al-2％Fe合金初生的富铁相来模拟熔体中的夹杂，通过加入变质剂来改变富铁相的形貌，从而改善其在熔体中的迁移，考察夹杂形貌对电磁分离效率的影响，利用电磁分离工艺制备了Al-5％Fe颗粒增强复合材料。 通过对实验合金组织和成分的分析，优化出最佳的工艺参数，当分离管径为10mm时，磁场强度0.04T，作用时间30s时可以获得最佳的分离效果；Mn作为变质剂加入合金熔体中能改变富铁相的形态，当锰与铁的摩尔比为1.5时，富铁相从针状变成块状或汉字状，这样更有利于其在熔体中迁移，Mn结合电磁过滤可以更加有效地去除合金中的富铁相，使铁相含量降低，净化熔体，提高合金的延伸率，延伸率可以从4.0％提高到29.2％；电磁分离制备的Al-5％Fe合金颗粒增强复合材料，近表面偏聚区铁的含量可以达到8％～8.5％，硬度最高可达到80 HV，并且中心区域和表层之间形成了很好的过渡层，这样可以使表面的耐磨层和基体之间有足够的结合强度。更多还原

【Abstract】 As a new technique of purification, electromagnetic purification (EMP) has become one of research focuses because of its non-pollution, high-efficiency and less effect of the different density between the melt and nonmetallic inclusions. High frequency alternating magnetic field was used in the experiment, It mainly makes use of the different conductivity between the iron-rich phase and melt, and can remove micron-grade iron-rich phase from metal melt by the extrusion force of electromagnetic field, hence realize the aim of melt purification.In this paper, electromagnetic body force has been deduced based on the Maxwell equation. And a calculation model which can calculate the migrated velocity of the solid grain in the molten metal has been set up. Further more, the influencing factor on the electromagnetic separation efficiency has been analyzed, including the magnetic field intensity, tube diameter, acting time and so on. Al-2%Fe alloys were used in the experiment performing to investigate the migrating behavior of the primary iron-rich phase in the quiescent melt. By adding Mn into melt to change the shape of iron-rich phase, the effect of the shape of iron-rich phase on electromagnetic purification efficiency was investigated, Al-5%Fe particle reinforced composite material was produced by electromagnetic purification process under high frequency magnetic field.The microstructure and component of the alloys were analyzed, the optimal parameters were optimized, when the tube diameter is 10mm, magnetic field intensity is 0.04T, and acting time is 30s, a very good separation effect can reach. The shape of iron-rich phase can be altered by adding the Mn, when Mn/Fe molar ratio is 1.3～1.5, the long need-like iron-rich phase was changed into piece or sphere, which was easy to migrate in the aluminum melt. Electromagnetic filtration with manganese can remove iron-rich phase better, drop the Fe content, and make separation efficiency enhanced, so that the elongation was enhanced further, from 4.0% to 29.2%. At last, Al-5%Fe particle reinforced composite material was fabricated, whose surface layer is rich in Fe(8%～8.5%) with hardness up to 80HV, and a transitional layer existed between the center area and the surface layer, making the reinforced phase and matrix jointed firmly.更多还原