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
中国广泛分布砂岩地层,其水力特性影响工程稳定性。干密度是土水特征曲线的重要影响因素,但其对砂岩土水特征曲线的影响机制尚不明确。为了探究不同干密度砂岩土水特征曲线及其微观特性,采用压力板仪开展了不同干密度砂岩土水特征试验,...中国广泛分布砂岩地层,其水力特性影响工程稳定性。干密度是土水特征曲线的重要影响因素,但其对砂岩土水特征曲线的影响机制尚不明确。为了探究不同干密度砂岩土水特征曲线及其微观特性,采用压力板仪开展了不同干密度砂岩土水特征试验,提出了考虑干密度的砂岩土水特征曲线模型,同时,基于扫描电镜(scanning electron microscope, SEM)和压汞测试分析了不同干密度砂岩微观特性,揭示了干密度对砂岩土水特征曲线影响的微观机理。研究表明:干密度越大,砂岩持水能力越强;干密度对砂岩进气值和残余饱和度均有影响,且砂岩进气值随着干密度的增大呈近似线性增长;不同干密度砂岩孔径分布均为单峰形态,随着干密度的增大,砂岩峰值孔隙半径逐渐减小;干密度较高的砂岩,颗粒排列紧密,孔隙半径较小,主要以中等和小孔隙为主,而干密度较低的砂岩,颗粒排列松散,孔隙半径大,包括大小不等的孔隙。研究可为非饱和砂岩工程安全提供一定的参考。展开更多
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.
文摘中国广泛分布砂岩地层,其水力特性影响工程稳定性。干密度是土水特征曲线的重要影响因素,但其对砂岩土水特征曲线的影响机制尚不明确。为了探究不同干密度砂岩土水特征曲线及其微观特性,采用压力板仪开展了不同干密度砂岩土水特征试验,提出了考虑干密度的砂岩土水特征曲线模型,同时,基于扫描电镜(scanning electron microscope, SEM)和压汞测试分析了不同干密度砂岩微观特性,揭示了干密度对砂岩土水特征曲线影响的微观机理。研究表明:干密度越大,砂岩持水能力越强;干密度对砂岩进气值和残余饱和度均有影响,且砂岩进气值随着干密度的增大呈近似线性增长;不同干密度砂岩孔径分布均为单峰形态,随着干密度的增大,砂岩峰值孔隙半径逐渐减小;干密度较高的砂岩,颗粒排列紧密,孔隙半径较小,主要以中等和小孔隙为主,而干密度较低的砂岩,颗粒排列松散,孔隙半径大,包括大小不等的孔隙。研究可为非饱和砂岩工程安全提供一定的参考。
