In this work, deformation behavior of AA2017-T4 at elevated temperatures was studied employing uni-axial tensile and creep experiments. Tensile tests were carried out at temperatures varying 150–500 °C under different strain rates then, a combination of neural network and dynamic material modeling was utilized to construct the processing maps. Furthermore, creep experiments were conducted to assess inelastic deformation behavior of the alloy at temperatures between 150 and 225 °C and stresses in the range of 150 to 230 MPa. Microstructural evaluations were carried out for determination of microstructural changes and formation of voids and cavities within the samples. The results showed that dynamic precipitation could occur during deformation at temperatures 175–225 °C leading to negative strain-rate sensitivity at true strains larger than 0.1. The main softening process was detected as dynamic recovery at temperatures higher than 250 °C however, dynamic recrystallization could also occur at low strain rates and temperatures higher than 400 °C. The activation energies for hot deformation were computed as 380.6 kJ mole⁻¹ at 250–350 °C and it was reduced to 224.7 kJ mole⁻¹ for the range of 350–500 °C. This showed the hard particle could significantly change rate of flow softening. The creep activation energy was determined as 169.5 kJ while the stress-exponent varied between 5.5 and 10.1 at temperatures between 150 and 225 °C indicating that dynamic recovery controlled by dislocation climb could be the governing creep mechanism.

Graphic Abstract

中文翻译：

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高温下AA2017的变形行为和空化

在这项工作中，使用单轴拉伸和蠕变实验研究了AA2017-T4在高温下的变形行为。然后在不同应变速率下于150–500°C的温度下进行拉伸测试，然后将神经网络和动态材料建模相结合来构造加工图。此外，进行蠕变实验以评估合金在150至225°C的温度和150至230 MPa范围内的应力下的非弹性变形行为。进行了微结构评估，以确定样品中的微结构变化以及空隙和空腔的形成。结果表明，在175–225°C的变形过程中可能会发生动态沉淀，从而导致在大于0.1的真实应变下产生负应变率敏感性。在高于250°C的温度下发现了主要的软化过程，即动态恢复，但在低应变速率和高于400°C的温度下也可能发生动态重结晶。计算得出热变形的活化能为380.6 kJ摩尔^-1在250-350℃，并且它减少了到224.7千焦耳摩尔^-1为350-500℃的范围内。这表明硬颗粒可以显着改变流动软化速率。蠕变活化能确定为169.5 kJ，而应力指数在150至225°C的温度范围内在5.5至10.1之间变化，这表明由位错爬升控制的动态恢复可能是主导的蠕变机制。

图形摘要