Micromechanics model for nanovoid growth and coalescence by dislocation emission: Loading and lattice orientation effects

• A micromechanics model for nanovoid growth by dislocation emission is developed.
• The influence of surface properties on dislocation emission from nanovoid is analyzed.
• A strong dependence of nanovoid evolution on the lattice and loading orientations.
• Effect of the void size on void growth and coalescence is studied.

Dislocation loops emitting from the surface of void is a viable mechanism at the nanoscale for void growth and coalescence, which has been confirmed by experimental observations and molecular dynamics simulations. Based on this mechanism, a micromechanics model was developed to investigate the crystal orientation on nanovoid growth and coalescence in fcc single crystals. In this paper, uniaxial tensile loading along four representative lattice orientations were considered. The surface effect of nanovoid on the critical stress and direction of nanovoid growth was also analyzed. The results showed a strong dependence of nanovoid evolution on loading and lattice orientation: in the case of uniaxial loading along the [1 1 0] direction void grew most easily, and the largest applied stress was required for the void growth under the unixial loading along the [1 1 2] direction. The void evolution showed a strong dependence on the size of nanovoid, especially for the void radius less than 10 nm.