Given the time and length scales in molecular dynamics simulations of dislocation-defect interactions, quantitative molecular dynamics results cannot be used directly in larger scale simulations or compared directly with experiment. A method to extract fundamental quantities from molecular dynamics simulations was proposed here. The first quantity was a critical stress defined to characterise the obstacle resistance. This mesoscopic parameter, rather than the obstacle 'strength' designed for a point obstacle, was to be used for an obstacle of finite size. At finite temperature, the present analysis of molecular dynamics simulations permitted the activation energy to be determined as a function of temperature. The results confirmed the proportionality between activation energy and temperature that was frequently observed by experiment. By coupling the data for the activation energy and the critical stress as functions of temperature, it was shown how the activation energy could be deduced at a given value of the critical stress.

Mesoscale Thermodynamic Analysis of Atomic-Scale Dislocation-Obstacle Interactions Simulated by Molecular Dynamics. G.Monnet, Y.N.Osetsky, D.J.Bacon: Philosophical Magazine, 2010, 90[7-8], 1001-18