Climb model of extended dislocations in f.c.c. metals

Abstract

A climb model of extended dislocations based on jog pair nucleation is proposed. The energy of an extended jog pair is computed for different stacking fault energies. The results show a critical jog size from which the extended jog pair may develop by glide. This critical size is related to the stacking fault energy. In a metal with low stacking fault energy, in which supersaturation of point defects is present, a climb model controlled by the rate of small loop nucleation near the existing dislocation is developed. The low activation energy involved in this mechanism is in good agreement with some recent experimental results. Furthermore, it is shown that the mixed part of an extended dislocation could climb more easily than the other parts by such a mechanism.