基于微观机理的5083合金高温流变本构方程

Micro-Mechanism-Based Constitutive Model for High Temperature Deformation of 5083 Alloy

为明确热塑性流变过程中应变温度、速率以及应变量对5083合金高温流变应力行为影响规律,本文采用Gleeble热模拟实验的方式,系统研究合金在不同应变温度(280˚C, 340˚C, 400˚C, 460˚C, 520˚C)和应变速率(0.01 s−1, 0.1 s−1, 1 s−1, 10 s−1)下材料的应力应变演变规律,并基于应力–位错关系和动态再结晶动力学,以临界应变为区分点,建立了合金的高温流变本构方程。结果表明:合金流变抗力与应变速率成正比,而与应变温度成反比。微观组织分析显示,高温高应变速率条件下合金发生明显的动态再结晶行为,且高应变温度与高应变速率能够获得更为细小的再结晶晶粒。所构建的本构方程能够准确预测5083合金的高温流变应力。In order to investigate the impact of strain temperature, rate, and amount on the high-temperature flow stress behavior of 5083 alloy during thermoplastic rheology, Gleeble thermal simulation experiments were conducted at various strain temperatures (280˚C, 340˚C, 400˚C, 460˚C, 520˚C) and strain rates (0.01 s−1, 0.1 s−1, 1 s−1, 10 s−1) to systermatically reveal the relationships between the strain and stress. By analyzing the stress-dislocation relationship and dynamic recrystallization kinetics, a high-temperature rheological constitutive equation for the alloy was established using the critical strain as a reference point. The results indicate that the rheological resistance of the alloy increases with the strain rate and decreases with the strain temperature. Microstructural analysis reveals that the alloy exhibits significant dynamic recrystallization behavior at high temperatures and strain rates, while finer recrystallized grains are obtained at high temperatures and strain rates. The developed constitutive equation proves to be effective in accurately predicting the high-temperature flow stress of 5083 alloy.