Plasticity driven growth of nanovoids and strength of aluminum at high rate tension: Molecular dynamics simulations and continuum modeling

In this paper the initial stage of nanovoids growth in monocrystal aluminum is studied with molecular dynamics simulations. The dependencies of critical negative pressure in simulated system on void radius, system size and temperature under high rate tension are obtained. It is shown that decrease of the ratio of void radius to system size causes an increase of system tensile strength, temperature rise leads to an almost linear drop of the tensile strength. We propose a continuum dislocation based model of nanovoids growth that is intended to describe the critical negative pressure in systems. Nucleation of dislocations near a growing void is taken into account through the equation for the probability of critical thermal fluctuation. Parameters of the model are determined in comparison with the molecular dynamics data. •Mechanism of void growth in aluminum is studied with the help of molecular dynamics.•It is shown, that the void growth is connected with the plastic flow around a void.•Continuum model of the dislocation driven void growth is proposed.•Arrhenius-type law applied for description of the dislocation nucleation rate.•Nucleation energy and activation volume are determined from the atomistic simulations.