Developed here was a theoretical model describing the mobility of a misfit screw dislocation dipole in a wire composite consisting of a stiff cylindrical substrate covered by a soft co-axial cylindrical film. A critical value of the film thickness, which was a function of the parameter measuring the stiffness of the film with respect to the substrate, was identified. It was observed that there existed two equilibrium positions of the misfit dislocation dipole (one stable and the other unstable) when the film was thicker than the critical value. The two equilibrium positions of the misfit dislocation dipole converged to a single saddle point equilibrium position which was neither stable nor unstable when the thickness of the film was at the critical value. Finally, there existed no equilibrium position of the misfit dislocation dipole when the thickness of the film was below the critical value. These features could be useful to the design of wire composites and to the dislocation-related plasticity analysis.

Misfit Dislocation Dipoles in Wire Composite Solids. X.Wang, E.Pan, P.W.Chung: International Journal of Plasticity, 2010, 26[9], 1415-20