中文摘要：

在镁合金水平双辊连续铸轧试验过程中,分别施加电磁场、超声波和超声电磁组合场,旨在改善AZ31B镁合金板带的综合力学性能。采用Leica DMI 5000 M金相显微镜、CSS-44100电子试验机和HV-1000硬度试验机等设备检测和分析电磁场、超声波或超声波电磁组合能场处理对AZ31B镁合金板带的微观组织和力学性能的影响。结果表明,常规、电磁场、超声波及超声电磁组合能场铸轧镁板带晶粒平均尺寸（直径）分别为120μm、25μm、27μm及15μm左右;电磁场处理使铸轧镁板带的抗拉强度、屈服强度、伸长率和硬度值比常规铸轧镁板带的分别提高15.7%、24.8%、22.7%和66.6%,超声波处理的分别提高13.8%、26.2%、11.4%和13.4%,超声电磁组合场处理的则分别提高17.1%,27.8%、31.8%和73.8%。这表明在镁合金铸轧过程中施加电磁场、超声波或超声电磁组合场均有利于细化晶粒,改善第二相在枝晶间的分布,提高力学性能,而超声电磁组合场的效果则更显著。同时分析和讨论超声空化效应及电磁效应对镁合金组织细化的作用机制。

英文摘要：

Electromagnetic, ultrasonic and the ultrasonic electromagnetic combination field is introduced into the experiment of horizontal twin-roll casting AZ31B magnesium alloy strip to improve its mechanical properties. The influence of electromagnetic, ultrasonic and the ultrasonic electromagnetic combination field treatment on the microstructure and the mechanical properties of the magnesium alloy strip is investigated by using Leica DMI 5000 M metallurgical microscope, CSS-44100 electronic testing machine and HV-1000 hardness tester, etc. Results of the tests show the distinct improvement on microstructure and the mechanical properties of the electromagnetic, ultrasonic and the ultrasonic electromagnetic combination field treated AZ31B strip. The general, electromagnetic, ultrasonic and the ultrasonic electromagnetic combination field cast-rolling AZ31B strip average grain diameter is 120 ~tm, 25 ~tm, 27 ~tm and 15 p.m, separately. The tensile strength, yield strength, elongation and hardness of the electromagnetic treated AZ31B strip are increased by 15.7%, 24.8%, 22.7% and 66.6%, ultrasonic treated AZ31B strip are increased by 13.8%, 26.2%, 11.4% and 13.4%, the ultrasonic electromagnetic combination field treated magnesium alloy strip are increased by 17.1%, 27.8%, 31.8% and 73.8%, separately, than that of the general strip. Electromagnetic, ultrasonic and ultrasonic electromagnetic combination field cast-rolling process enhances the mechanical properties and refines microstructure of AZ31B. At the same time, the effect mechanism of grain refinement during cast-rolling process with ultrasonic cavitation and electromagnetic field effect are discussed and analyzed.