通过平面应变压缩试验获得2219铝合金在变形温度320~480℃、应变速率0.1~10 s^(-1)、最大真应变1.2条件下的压缩变形行为;基于试验得到的真应力-真应变数据和Arrhenius双曲正弦模型,分别建立峰值应力本构方程和应变补偿本构方程,获得合...通过平面应变压缩试验获得2219铝合金在变形温度320~480℃、应变速率0.1~10 s^(-1)、最大真应变1.2条件下的压缩变形行为;基于试验得到的真应力-真应变数据和Arrhenius双曲正弦模型,分别建立峰值应力本构方程和应变补偿本构方程,获得合金的热变形激活能和应力指数,分析合金的变形机制。结果表明:在平面应变压缩过程中,合金的流变应力先迅速升高,达到峰值应力后稍有下降,最后趋于稳定;流变应力随变形温度的升高或应变速率的降低而降低。峰值应力本构方程预测的真应力与试验值的最大相对误差为4.57%;应变补偿的本构方程预测得到的真应力与试验值的平均绝对相对误差为2.62%,线性相关系数为0.9953。建立的本构方程都能够准确预测2219铝合金在平面应变压缩变形过程中的流变应力。在整个变形过程中热变形激活能范围为135.138~145.410 k J·mol^(-1),应力指数范围为5.920~6.930,表明变形时合金主要的扩散机制为晶格扩散,主要的变形机制为位错攀移。展开更多
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...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.展开更多
文摘通过平面应变压缩试验获得2219铝合金在变形温度320~480℃、应变速率0.1~10 s^(-1)、最大真应变1.2条件下的压缩变形行为;基于试验得到的真应力-真应变数据和Arrhenius双曲正弦模型,分别建立峰值应力本构方程和应变补偿本构方程,获得合金的热变形激活能和应力指数,分析合金的变形机制。结果表明:在平面应变压缩过程中,合金的流变应力先迅速升高,达到峰值应力后稍有下降,最后趋于稳定;流变应力随变形温度的升高或应变速率的降低而降低。峰值应力本构方程预测的真应力与试验值的最大相对误差为4.57%;应变补偿的本构方程预测得到的真应力与试验值的平均绝对相对误差为2.62%,线性相关系数为0.9953。建立的本构方程都能够准确预测2219铝合金在平面应变压缩变形过程中的流变应力。在整个变形过程中热变形激活能范围为135.138~145.410 k J·mol^(-1),应力指数范围为5.920~6.930,表明变形时合金主要的扩散机制为晶格扩散,主要的变形机制为位错攀移。
文摘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.
