Abstract Hardening behavior with its ultimate deterioration (or softening) after uniform deformation limit and strain rate sensitivity of metals at elevated temperatures are characterized. To avoid non-uniqueness in the identification procedure based on only simple tension test, an inverse identification procedure involving not only the simple tension test, but also the creep test is newly proposed. Moreover, for better understanding of creep behavior, analytical and numerical creep models are developed for the generalized multiplicative constitutive law accounting for hardening, softening, and strain rate sensitivity. Robust parametric studies are presented to explore the effect of material and process parameters on creep deformation behavior, which is also effectively used for the two-step characterization procedure of the proposed hardening model. The identification procedure for the multiplicative constitutive model is demonstrated using AZ61 Mg alloy sheet, which provides good correlations between calculated and measured stress-strain curves and creep strains under different strain rates and prior-creep strains.

中文翻译：

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考虑应变软化和应变速率的乘法塑性硬化模型：模型参数的理论推导与简单拉伸蠕变试验表征

摘要 表征了金属在高温下均匀变形极限和应变速率敏感性后的硬化行为及其最终劣化（或软化）。为避免仅基于简单拉伸试验的识别过程的非唯一性，新提出了一种不仅涉及简单拉伸试验，还涉及蠕变试验的逆识别过程。此外，为了更好地理解蠕变行为，开发了分析和数值蠕变模型，用于解释硬化、软化和应变率敏感性的广义乘法本构定律。提出了稳健的参数研究，以探索材料和工艺参数对蠕变变形行为的影响，这也有效地用于所提出的硬化模型的两步表征程序。使用 AZ61 镁合金板演示了乘法本构模型的识别过程，它提供了计算和测量的应力-应变曲线与不同应变率和先验蠕变应变下的蠕变应变之间的良好相关性。