The effect of vacancy diffusion on crack initiation and propagation in two-dimensional Lennard-Jones crystals was investigated numerically using a molecular statics approach. A crystal was represented by a basal plane of a hexagonal closed-packed lattice and the seed vacancy was created by removing one atom. The crystal was subjected to tension by displacing one of its boundaries. The vacancy was allowed to diffuse within some rectangle so that its migration to the crystal surface was prevented. It was assumed that the event of an exchange between the vacancy and the neighbouring atom will take place between two sequential loading steps and that there was no preferred direction for a jump, which led to the vacancy’s random walk. It was shown that the migrating vacancy not only results in dislocation formation but also led to formation of nanovoids and nanocracks. Since the vacancy migration was random, the patterns of structural changes leading to nanovoids, nanocracks and to the fracture were different for each numerical test.

Effect of Vacancy Diffusion on Crack Initiation and Propagation in the Lennard-Jones Crystal Subjected to Tension. O.G.Vinogradov: International Journal of Fracture, 2011, 171[2], 155-62