By recourse of computational mechanics, back-stresses are unveiled as a major source for the increase in work hardening during forming of hexagonal close-packaged (hcp) metals. Polycrystalline visco-plastic self-consistent (VPSC) and crystal plasticity finite element modelling (CPFEM) simulations of tensile uniaxial experiments were used along with experimental texture information. Simulations took into account the analogous variation in the critical resolved shear stress (CRSS) values of each slip family that could result from an increase in the test temperature. As the CRSS ratio between secondary and primary slip families increased, two different contributions to the variation of the work hardening rate were observed depending on the simulation framework: (i) a decrease in the work hardening rate in VPSC simulations attributed to texture evolution or geometrical hardening and (ii) an increase in the work hardening rate in CPFEM simulations due to back-stresses. While geometrical hardening is present in both simulation frameworks, only CPFEM is able to capture the influence of back-stresses on the increase of the work hardening rate with temperature. The results provided here contribute to a better understanding of the deformation mechanisms present in warm forming of hcp metals, showing also that CPFEM is a better simulation framework to study warm forming of hcp metals.

通过求助于计算力学，背应力被揭示为六方密排（hcp）金属成形过程中增加工作硬化的主要来源。拉伸单轴实验的多晶粘塑性自洽（VPSC）和晶体可塑性有限元建模（CPFEM）模拟与实验纹理信息一起使用。模拟考虑了每个滑移族的临界解析剪切应力（CRSS）值的类似变化，这可能是由于测试温度的升高而引起的。随着次生和主要滑移族之间的CRSS比率的增加，根据模拟框架，观察到了对工作硬化率变化的两种不同贡献：（i）归因于纹理演变或几何硬化的VPSC模拟中的加工硬化率降低，以及（ii）由于背应力而导致的CPFEM模拟的加工硬化率提高。虽然在两个仿真框架中都存在几何硬化，但是只有CPFEM才能捕获背应力对工作硬化率随温度增加的影响。此处提供的结果有助于更好地理解hcp金属热成形中存在的变形机制，也表明CPFEM是研究hcp金属热成形的更好的模拟框架。只有CPFEM才能捕获背应力对加工硬化率随温度升高的影响。此处提供的结果有助于更好地理解hcp金属热成形中存在的变形机制，也表明CPFEM是研究hcp金属热成形的更好的模拟框架。只有CPFEM才能捕获背应力对加工硬化率随温度升高的影响。此处提供的结果有助于更好地理解hcp金属热成形中存在的变形机制，也表明CPFEM是研究hcp金属热成形的更好的模拟框架。