Computer simulation of interacting dislocation motion resisted by pointlike barriers

Abstract

We consider interacting dislocations of like Burgers vectors in glide through random arrays of pointlike barriers. Two configurations are considered: first, many dislocations in the same glide plane; second, many dislocations on parallel glide planes, initially configured in a low-angle-tilt boundary. In our simulation, the glide plane(s) are periodic in all directions. In previous work, we determined the dimensionless athermal critical resolved shear stress for a single dislocation. The present results show that the athermal critical resolved shear stress for glide of a system of interacting dislocations τa* is related to that for a single dislocation system τ0* by the equation τa*=τ0* exp{−(π/h)[1/3λ (βc)1/2]1/2}, where h is a dimensionless average dislocation spacing, λ is a dimensionless dislocation line tension, and βc is a dimensionless barrier strength. The resulting dislocation morphologies can be explained in terms of the above parameters. Also, the stability of a moving low-angle-tilt boundary can be predicted.