通过动态热/力模拟试验机对铝锰镁合金进行热压缩变形, 分析了合金在热变形过程中的流变应力, 应用Arrhenius关系式对合金在热变形峰值阶段和稳态阶段的热变形激活能进行求解, 建立了流变应力本构方程, 并将本构方程的计算值与试验值进行对比。结果表明: 试验合金在热变形过程中表现出了明显的动态软化特征, 发生了动态回复和动态再结晶; 在高应变速率、高变形温度下, 流变应力曲线呈现多峰值的不连续动态再结晶特征; 试验合金在峰值阶段和稳态阶段的热变形激活能分别为164.54, 187.26 kJ·mol-1; 流变应力本构方程的计算结果与试验结果相符。

Al-Mn-Mg alloy was compressed at elevated temperature by dynamic thermal/mechanical simulation tester and the flow stress during hot deformation was studied. The Arrhenius equation was used to calculate the thermally-activated energy at peak and steady states of flow stress curves, constitutive equations were established, and the calculated results of the constitutive equation were compared with the experimental results. The results show that dynamic softening character of the alloy was remarkable because dynamic restore and dynamic recrystallization occurred during hot deformation, however, the flow stress curves displayed uncontinuous dynamic recrystallization under the conditions of high strain rate and elecated temperature. The thermally-activated energy at peak and steady states were 164.54 kJ·mol-1 and 187.26 kJ·mol-1, respectively. The calculated values of flow stress by constitutive equation were coincide with experimental ones.