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Effect of dislocation density evolution on the thermomechanical response of metals with different crystal structures at low and high strain rates and temperatures. (English) Zbl 1126.74011
From the summary: We investigate the contribution of plastic strain evolution of mobile and forest dislocation densities to thermal and athermal components of polycrystalline metals flow stress. The thermomechanical response is characterized here for body centered cubic, face centered cubic and hexagonal close-packed structures of metals at low and high strain rates and temperatures. Consequently, the simulation of the plastic flow stress for these metals is developed based on the concept of thermal activation energy, the additive decomposition of the flow stress, dislocations interaction mechanisms and the role of dislocation dynamics in crystals. The material parameters of the proposed modeling are physically defined and related to nano- and micro-structure quantities. On the other hand, the hardening parameters of each kind of metal structures are presented in two different forms; physically based definition which is developed based on the aforementioned concepts, and empirical relation which is used by several authors and is based on experimental observations. Several experimental data obtained by different authors for niobium, tantalum, vanadium, oxygen-free high-conductivity copper, and titanium are used in evaluating the proposed models. Good correlation is observed between the proposed predictions and experimental observations.

MSC:
74E15 Crystalline structure
74A60 Micromechanical theories
82D35 Statistical mechanical studies of metals
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