2099 Al-Li合金热变形本构模型（英文）

Constitutive Analysis to Predict High-Temperature Flow Stress in 2099 Al-Li Alloy

采用高温等温压缩试验并利用修正后的流变曲线，研究了2099Al-Li合金在变形温度为300～500℃，应变速率为O．001～10s^-1，变形量（真应变）为0．7条件下的流变行为。结果表明：可用包含Z参数的双曲正弦形式来表征变形温度和应变速率对2099Al—Li合金热变形行为的影响；将应变作为影响因素，求解了不同应变量下的材料常数，并构建了考虑应变的本构模型；统计分析结果表明，除了在变形温度为300℃，应变速率为10S。之外，该模型能够很好的预测2099Al-Li合金高温流变行为。

Constitutive analysis for hot working of 2099 aluminum-lithium （Al-Li） alloy was carried out employing friction and temperature corrected flow curves from isothermal hot compression test, in a wide range of temperatures 300-500 ℃, at strain rates 0.001-10 s^-1 and strains 0.1-0.7. The effects of temperature and strain rate on hot deformation behavior were represented in terms of a hyperbolic sine type Zener-Holloman （Z） parameter equation. The influence of strain was incorporated in the constitutive analysis by considering the effect of strain on material constants. Consequently, a model to predict the high-temperature flow behavior of 2099 Al-Li alloy has been established. The true stress-true strain curves predicted by the developed model are in good agreement with the experiment results throughout the deformation conditions except at 300℃ in 10 s^-1.