Dynamics of atomic species involved in shear-induced displacements at sliding symmetrical grain boundaries: a numerical study

Molecular dynamics methods have been used to study the mechanical response under shear of two Cu systems containing symmetrical tilt and twist grain boundaries, respectively. The investigation focuses on the mechanism of localized atomic displacements during plastic deformation. It is shown that grain boundary sliding generates a perturbed layer of atomic species, with thickness increasing approximately with the square root of time. The dynamics of the atomic displacement processes, even though apparently stochastic, is intimately connected with the local density experienced by atoms under shear.