Combined model of dislocation motion with thermally activated and drag-dependent stages

A computational model is developed to study the effect of coupling of thermally activated and drag-dependent processes during dislocation motion through an array of obstacles in metals. The model explicitly includes three successive, reiterative stages typical of such motion: the thermally activated break-off from an equilibrium position; accelerated drag-dependent motion; and the transition to the next equilibrium position controlled by the two previous stages. Calculation results are presented over a wide range of dislocation velocities, applied stresses and temperatures for a prototype f.c.c. metal close to copper. The presented model is also the first step for explaining quantitatively experimental findings regarding the effects of the SN transition on dislocation motion and plasticity in superconductors.