A model was proposed which demonstrated the effect of a free surface upon the lattice resistance experienced by a moving dislocation in a nanodimensional system. The effect was seen as an enhanced dislocation velocity, due to the proximity of the dislocation line to the surface. In order to verify this, molecular dynamics simulations were made of an edge dislocation in body-centered cubic molybdenum. The results were found to be in agreement with numerical analyses of the model. A reduction in the effect at higher stresses and temperatures, as revealed by the simulations, confirmed the role played by lattice resistance in the observed change in dislocation velocity.

Lattice Resistance to Dislocation Motion at the Nanoscale. A.Dutta, M.Bhattacharya, P.Barat, P.Mukherjee, N.Gayathri, G.C.Das: Physical Review Letters, 2008, 101[11], 115506