The Influence of Many Body Interactions in the Stress-Velocity Relation of a Single Dislocation in a 2D Lattice.

Abstract

ABSTRACTThe stress-velocity relation of a single dislocation moving in a 2-D lattice has been studied using interactive molecular dynamic simulations. A hybrid interatomic model potential which couples Lennard-Jones(LJ) potential and the Embedded Atom Model (EAM) potential, is used to include radial and many body interactions. Both parts are assembled by a parameter so that the potential can be changed to describe a pure radial interaction to a strong many body interaction in a continuous way. Setting up a constant-stress scenario, the movement of a single dislocation is tracked from zero velocity state, up to a terminal velocity state. The external stress vs. terminal velocity curves have been obtained in the subsonic regime for different values of the coupling parameter. Non-linear relations are found velocity regime 0.1ct to 0.6ct, where ct is the transverse speed of sound. Results have been analyzed using an augmented Peierls model to seek the connection between atomic scale, continuum variables and the limiting speed of dislocations