电磁场施加方式对半连续铸造镁合金锭坯组织与性能的影响

Effect of Different Electromagnetic Field Application Ways on Microstructures and Mechanical Properties of Semi-Continuous Cast Magnesium Alloy Billets

摘要:

采用不同电磁场施加方式和半连续铸造制备Φ200 mm AZ31镁合金锭坯。研究电磁场施加方式对AZ31锭坯微观组织和力学性能的影响。结果表明，与常规直接水冷半连铸锭坯相比，单感应线圈通电(LFEC)或两组感应线圈同时通电(LFEVC)来铸造锭坯时，组织细化，第二相(β-Mg17Al12)变得细小弥散，锭坯横截面边部与中心部位晶粒大小差别明显降低，LFEVC铸造的锭坯比LFEC铸造的更为明显；两种电磁场施加方式均有利于主合金元素在锭坯中均匀分布，宏观偏析在很大程度上得到抑制；两种电磁场施加方式均有利于锭坯的

Abstract:

Using different electromagnetic fields application ways, AZ31 magnesium alloy was semi-continuously cast into billets with diameter of 200 mm. The effects of the different electromagnetic fields application ways on the microstructures and mechanical properties of AZ31 billets were investigated. The results show that compared with the conventional direct-chill semi-continuous cast billets, the microstructures in the entire cross section of the AZ31 billets cast in the single alternating magnetic field or the combination of alternating magnetic field and stationary magnetic field are significantly refined, the β-Mg17Al12 phases become fine and dispersive, the difference of the grain size between the border and center of the billet is reduced, and the difference of the microstructures in the billet cast in the combination of alternating magnetic field and stationary magnetic field is smaller than that of the single alternating magnetic field casting. The two electromagnetic field application ways are all beneficial to the homogeneous distributing of the alloy main elements in the cast billets, to great suppressing of macro-segregation and to improving of the mechanical properties of the billets. Compared with the properties of the conventional cast billets, the yield strength and the ultimate tensile strength of the billet cast in the electromagnetic field are increased by 50~60 MPa and 40~50 MPa, respectively, and the elongation is doubled.