电磁连铸AZ31镁合金的组织、性能和偏析

Structure,Property and Segregation of Electromagnetic Continuous Casting of Magnesium Alloy AZ31

针对镁合金的加工性能问题,采用电磁连铸和普通连铸方法进行了AZ31镁合金的连铸实验研究,对有、无电磁场作用下的铸坯凝固宏观、微观组织和力学性能、成分偏析进行了对比分析,并通过试样断口的扫描,分析镁合金的断裂机制。结果表明:与普通连铸相比,电磁连铸的镁合金组织细小、均匀,树枝晶破碎,可实现全等轴晶化;铸坯力学性能(尤其是塑性性能)有显著提高,抗拉强度、屈服强度和伸长率分别提高17%,50%和81%,且断口形貌呈现韧性断裂特征;铸坯中的成分偏析下降73%(Zn)和67%(Mn)。

Two methods of electromagnetic continuous casting（EMCC） and normal continuous casting were carried out aiming at improving the formability of AZ31 magnesium alloy .The macrostructure,microstructure,formability and component segregation of both billets were compared and the fracture mechanism of magnesium alloy was analyzed by fractography of magnesium alloy sample.The result showed that the EMC alloy crystal was much finer and more uniform than normal cast billet,and its dendrites crystal was fragmentized,full equiaxed grains came forth.Mechanical properties of EMCC cast（plasticity especially） was enhanced prominently than normal casting billets,its tensile and yield strength and elongation increased by 17%,50% and 81% than normal billet,respectively.The break appearance had a toughness break character and the element segregation was decreased by 73% for Zn and 67% for Mn,respectively.