Mg-10Gd-3Y-0.4Zr合金高温变形过程的修正本构模型研究

Modified constitutive behavior model of Mg-10Gd-3Y-0.4Zr alloy during high-temperature deformation process

为了研究Mg-10Gd-3Y-0.4Zr镁合金在高温变形过程中的流变行为,在573^773 K温度范围和0.001^1.0 s^(-1)应变速率范围内进行了热压缩实验。实验结果表明,流变应力随着温度的升高和应变速率的降低而降低。流变应力的变化与应变变化有关,建立了考虑应变补偿的改进Arrhenius本构方程。然而,具有应变补偿的Arrhenius模型在低温和高应变速率下显示出与真实应力-应变曲线的明显偏差。误差分析表明,Arrhenius模型中的材料参数不仅与应变有关,还与应变速率和变形温度有关。因此,通过将修正模型中的计算应力与实验应力进行比较,考虑高温压缩过程中材料参数与成形参数之间的关系,建立了修正的Arrhenius本构模型。

To investigate the flow behavior of Mg-10Gd-3Y-0.4Zr magnesium alloy during high-temperature deformation,the thermal compression experiments were conducted in the temperature range of 573−773 K and strain rate range of 0.001−1.0 s^(−1).The experimental results showed that the flow stress decreases with the increase in temperature and decrease in strain rate.The variation of rheological stress was related to the strain change and the improved Arrhenius constitutive equation considering the strain compensation was established.However,the Arrhenius model with strain compensation showed obvious deviation in the true stress−strain curves at low temperature and high strain rate.The error analysis shows that the material parameters in Arrhenius model were not only related to strain,but also to strain rate and deformation temperature.Therefore,a modified Arrhenius-type constitutive model was established by considering the relationship between the material parameters and the forming parameters in high-temperature compression by comparing the calculated stress in the modified model with the experimental stress,the modified Arrhenius model established in this study can accurately predict the rheological stress of Mg-10Gd-3Y-0.4Zr magnesium alloy in all conditions during the high-temperature compression.