ABSTRACT Models describing the constitutive flow behaviour of a metallic material are desired for appropriate process design and realization of defect-free components. In this study, constitutive equations based on the hyperbolic-sinusoidal Arrhenius-type model have been developed to define the hot deformation characteristics of a CoCrFeMnNi high-entropy alloy. The experimental true stress-true strain data were generated over a wide temperature (1023–1423 K) and strain rates (10−3–10 s−1) ranges. The impact of strain rate and temperature on deformation behaviour was further characterized through a temperature compensated strain rate parameter, i.e. Zener-Hollomon parameter. Additionally, a mathematical relation was employed to express the influence of various material constants on true-strain ranging from 0.2 to 0.75. Typical third order polynomial relations were found to be appropriate to fit the true-strain dependency of these material constants. The accuracy of the developed constitutive equations was evaluated by using the average absolute relative error (AARE) and correlation coefficient (R); the obtained values were 7.63% and 0.9858, respectively, suggesting reasonable predictions. These results demonstrate that the developed constitutive equations can predict the flow stress behaviour of the alloy with a good accuracy over a wide range of temperature and strain rate conditions and for large strains.

中文翻译：

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CoCrFeMnNi高熵合金热变形行为的本构建模

摘要 描述金属材料本构流动行为的模型对于适当的工艺设计和实现无缺陷部件是需要的。在本研究中，开发了基于双曲正弦 Arrhenius 型模型的本构方程来定义 CoCrFeMnNi 高熵合金的热变形特性。实验真实应力-真实应变数据是在很宽的温度 (1023–1423 K) 和应变率 (10-3–10 s-1) 范围内生成的。应变率和温度对变形行为的影响通过温度补偿应变率参数，即 Zener-Hollomon 参数进一步表征。此外，还采用数学关系来表示各种材料常数对 0.2 至 0.75 范围内的真实应变的影响。发现典型的三阶多项式关系适用于拟合这些材料常数的真实应变依赖性。使用平均绝对相对误差（AARE）和相关系数（R）来评估所建立的本构方程的准确性；所得值分别为 7.63% 和 0.9858，表明预测合理。这些结果表明，开发的本构方程可以在很宽的温度和应变率条件下以及大应变下以良好的精度预测合金的流动应力行为。所得值分别为 7.63% 和 0.9858，表明预测合理。这些结果表明，开发的本构方程可以在很宽的温度和应变率条件下以及大应变下以良好的精度预测合金的流动应力行为。所得值分别为 7.63% 和 0.9858，表明预测合理。这些结果表明，开发的本构方程可以在很宽的温度和应变率条件下以及大应变下以良好的精度预测合金的流动应力行为。