MgAlLiZnTi轻质高熵合金的热变形行为与热加工图研究

Thermal Deformation Behavior and Thermal Processing Diagram Study of MgAlLiZnTi Lightweight High-Entropy Alloy

摘要:

采用Gleeble-3500 热/力模拟试验机，在变形温度为250—350 ℃、应变速率分别为0.001、0.01、0.1和1 s^-1、真应变量分别为0.3、0.45、0.6的条件下，对Mg₅₄Al₂₂Li₁₁Zn₁₁Ti₂轻质高熵合金进行热压缩实验。基于Arrhennius模型对热压缩实验数据进行拟合，建立合金的本构方程，并绘制该合金在不同真应变下的热加工图。结果表明：在实验条件下，合金的热变形过程为加工硬化和动态再结晶为主的动态软化，且该合金的流变应力值与应变速率呈正相关，与变形温度呈负相关；该合金的热加工图表明，最佳的热加工工艺参数为变形温度335—350 ℃、应变速率1×10^-3—1 s^-1。

Abstract:

The Gleeble-3500 thermal/force simulation tester was used to carry out thermal compression experiments on the Mg₅₄Al₂₂Li₁₁Zn₁₁Ti₂ lightweight high-entropy alloy at deformation temperatures of 250—350 °C， strain rates of 0.001， 0.01， 0.1 and 1 s^-1， and true strain rates of 0.3， 0.45 and 0.6. Based on the Arrhenius model， the thermal compression experimental data were fitted to establish the constitutive equations of the alloy and to plot the thermal processing map of the alloy under different true strains. The results show that under the experimental conditions， the thermal deformation process of the alloy is mainly dynamic softening through work-hardening and dynamic recrystallization， and the rheological stress values of the alloy are positively correlated with the strain rate and negatively correlated with the deformation temperature. The thermal processing diagram of the alloy indicates that the optimum thermal processing process parameters are deformation temperatures of 335—350 °C and a strain rate of 1×10^-3—1 s^-1.