A recently developed single shear specimen (SSS) was used to investigate the thermo-viscoplastic behavior of 2024-T351 aluminum alloy (AA2024-T351) under simple shear stress state. Shear stress-shear strain relations over a wide range of strain rates, covering low (0.001 and 0.1 s⁻¹), medium (10 s⁻¹), high (3000 and 6000 s⁻¹) and very high (14000-49000 s⁻¹) regimes and at initial temperatures from 293 to 573 K were obtained experimentally. The results show that: (1) at 293 K, AA2024-T351 exhibited negligible strain rate sensitivity at strain rates below 6000 s⁻¹, and the effect of strain rate became obvious at strain rates above 14000 s⁻¹; (2) dynamic strain aging (DSA) occurred at temperatures between 373 and 573 K and strain rates below 6000 s⁻¹; (3) strain rate sensitivity of the material was strongly affected by DSA, and bell-shaped strain rate sensitivity curves were observed; (4) with an increase in temperature, peak values of the bell-shaped strain rate sensitivity curves shifted to higher strain rates. A constitutive model taking the advantages of Johnson-Cook model, Khan-Huang-Liang model, Nemat-Nasser-Li model and Wang-Guo-Gao model was developed for deformation behavior description, with the effects of viscous drag on dislocation motion and DSA considered. The experimental flow stress curves were compared to the model predictions, and a good agreement was observed. To validate the constitutive model independently of the experiments used for the identification of the model parameters, numerical simulations of Taylor impact tests were performed. A good agreement between experimental and numerical post-test specimens, in terms of mushroom shaped specimen head and reduced specimen length, was observed. According to the numerical results, strain rates varied largely between 10³ and 10⁶ s⁻¹ during Taylor impact tests. Besides, numerical simulations of Taylor impact tests were performed again using the constitutive model excluding the viscous drag component, and less accurate numerical results were obtained. It implies that for precise computations of engineering applications, the actual strain rate should be considered in the establishment of constitutive models.

最近开发的单剪切试样 (SSS) 用于研究 2024-T351 铝合金 (AA2024-T351) 在简单剪切应力状态下的热粘塑性行为。剪切应力-剪切应变关系在很宽的应变率范围内，包括低（0.001 和 0.1 s ^-1）、中（10 s ^-1）、高（3000 和 6000 s ^-1）和非常高（14000-49000 s）^-1 ) 状态和初始温度从 293 到 573 K 是通过实验获得的。结果表明：（1）在293 K时，AA2024-T351在低于6000 s ^{-1 的}应变率下表现出可忽略不计的应变率敏感性，在14000 s ^-1以上的应变率下应变率的影响变得明显; (2) 动态应变时效 (DSA) 发生在 373 到 573 K 之间的温度和低于 6000 s ^{-1 的}应变率; (3)材料的应变率灵敏度受DSA影响较大，观察到钟形应变率灵敏度曲线；(4) 随着温度的升高，钟形应变率灵敏度曲线的峰值向更高的应变率移动。结合Johnson-Cook模型、Khan-Huang-Liang模型、Nemat-Nasser-Li模型和Wang-Guo-Gao模型的优点，建立了本构模型进行变形行为描述，并考虑了粘滞阻力对位错运动和DSA的影响经过考虑的。将实验流动应力曲线与模型预测进行比较，观察到良好的一致性。为了独立于用于识别模型参数的实验来验证本构模型，进行了泰勒冲击试验的数值模拟。在蘑菇形试样头和减少的试样长度方面，观察到实验试样和数值试验后试样之间的良好一致性。根据数值结果，应变率在 10³和 10 ⁶ s ^-1在泰勒冲击试验期间。此外，使用排除粘性阻力分量的本构模型再次进行了泰勒冲击试验的数值模拟，得到的数值结果不太准确。这意味着对于工程应用的精确计算，在建立本构模型时应考虑实际应变率。