Yield strength of nanocrystalline materials under high-rate plastic deformation

Abstract

A high rate plastic deformation of fine grained materials has been considered as a result of com peting processes of dislocation gliding in the grains and grain boundary sliding. A structural model has been proposed for describing the grain boundary sliding as a dominant mechanism of plasticity of nanocrystalline metals. The dependence of the yield strength on the material properties, temperature, and deformation rate has been studied numerically. For the adequate description of the experimental data and molecular dynamics calculations, it is necessary to take into account two parameters, namely, the barrier stress, which is depen dent on the elastic constants of a material, and the boundary viscosity, which is substantially dependent on temperature.

Strain rate sensitivity and deformation kinetics of ECAPed aluminium over a wide range of strain rates

“…In fact, an analytical work by Borodin et al [46] also suggested that the viscous effect is still a dominant factor at high strain rates even in nano-materials. In such cases, the boundary viscosity acts as the viscous source for plastic deformation.…”

Compressive behavior and deformation kinetics of ultrafine grained aluminum processed by equal channel angular pressing

“…Actually, analytic works by Borodin et al [82] and Weinberger et al [83] also suggested that the viscous effect is even a dominant factor during high strain rate deformation even in NC materials. In such case, the boundary viscosity acts as the viscous source for plastic deformation.…”

Structural model of mechanical twinning and its application for modeling of the severe plastic deformation of copper rods in Taylor impact tests

“…In accordance with (Borodin and Mayer, 2012;Krasnikov et al, 2011;Mayer et al, 2013), the total annihilation rate of dislocations per unit volume of substance can be expressed in…”