Dislocation dynamics simulations were used to study the cyclic stress-strain response of crystals which contained misfitting particles. The strength differential, reflecting the difference between the magnitudes of the tensile and compressive flow strengths during continuous loading, was examined. The model consisted of a spherical particle, and a single Frank-Read source, on a specific slip-plane within a face-centered cubic crystal. Attention was focused on the dislocation glide behavior, as affected by the misfit elastic field even when the slip-plane did not intersect the particle. The multiplication of dislocations from the single source, the formation of pile-up loops, and the unraveling of loops during load reversal were all reproduced by the simulation. It was observed that the existence of a misfitting particle gave rise to a strength differential. This was a phenomenon which was of a fundamentally different nature in comparison with the Bauschinger effect. The back-stress concept was used to analyze the simulation results.

A Dislocation Dynamics Study of Strength Differential in Particle-Containing Metals during Cyclic Loading. R.W.Leger, T.A.Khraishi, Y.L.Shen: Journal of Materials Science, 2004, 39[11], 3593-604