The vibration and de-pinning of an edge dislocation in Al initially anchored at an array of voids was studied by molecular dynamics simulations. The dislocation behaviour was studied under cyclic loading in the frequency range 10–160 GHz and varying stress amplitudes. It was found that for stress amplitudes smaller than 50 MPa the vibration amplitude and phase shift were in good agreement with an atomistically informed Granato–Lücke model. At larger stresses relativistic effects cannot be neglected anymore. The de-pinning stress was determined under quasistatic and cyclic loading conditions. For frequencies close to the resonant frequency de-pinning of the dislocation was observed at significantly lower stresses than under quasistatic loading. Possible consequences of this dynamical de-pinning effect were discussed.

Atomistic Simulation of Dislocation–Void Interactions under Cyclic Loading. Y.Cheng, E.Bitzek, D.Weygand, P.Gumbsch: Modelling and Simulation in Materials Science and Engineering, 2010, 18[2], 025006