Asymmetric cyclic plasticity model in nanotwinned metals based on correlated dislocation mechanism
Abstract
<p indent="0mm">Nanotwinned metals possess advantages in terms of strength, toughness, and fatigue resistance, demonstrating significant engineering application value. The plastic deformation mechanism of nanotwinned metals is markedly different from that of traditional polycrystalline metals. Classical mechanics theories struggle to accurately describe their mechanical behavior, thereby necessitating the targeted establishment of a constitutive mechanics theory. Therefore, this study combines the discrete element model and dislocation pile-up long-range interaction effect based on the unique correlated dislocation mechanism of nanotwinned metals with preferred orientation. This study proposes a constitutive model that can describe the asymmetric cyclic plastic behavior of nanotwinned metals, capturing the history-independent cyclic plastic behavior and the Masing phenomenon. The model also describes the strain-hardening phenomenon induced by long-range back stress under reloading. Furthermore, a dissipated energy rate formula for predicting fatigue life is derived based on thermodynamic theory and the correlated dislocation and dislocation long-range interaction mechanism. These results offer theoretical significance for the engineering application of nanotwinned metals with preferred orientation.</p>
