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通过静态拉伸试验机和高应变速率冲击拉伸试验装置,对AZ31挤压镁合金分别进行了不同应变率下拉伸力学性能的试验,获得了各应变速率下完整的应力-应变曲线。并通过扫描电镜对其拉伸断口进行分析。结果表明,其屈服应力、拉伸强度随着应变速率的增加而增加,失稳应变则随着应变速率的增加而有所减小;而弹性模量则对应变率不敏感。采用Johnson-Cook材料模型描述AZ31镁合金应变速率相关的应力应变本构模型,其拟合结果和实验结果基本相吻合。扫描电镜断口分析结果表明,动态和静态的断裂方式基本相同,都是以准解理断裂特征为主,局部区域伴有解理断裂。
Through the static tensile testing machine and high strain rate impact tensile testing device, the tensile mechanical properties of AZ31 magnesium alloy under different strain rates were tested respectively, and the complete stress-strain curve was obtained under different strain rates. The tensile fracture was analyzed by SEM. The results show that the yield stress and tensile strength increase with the increase of strain rate, and the instability strain decreases with the increase of strain rate. The elastic modulus is not sensitive to strain rate. Johnson-Cook material model is used to describe the stress-strain constitutive model of strain rate of AZ31 magnesium alloy. The fitting results are in good agreement with the experimental results. The fracture analysis results of SEM show that the dynamic and static fracture modes are basically the same, and are mainly quasi-cleavage fracture features, and the local regions are accompanied by cleavage fractures.