A model was proposed for the dynamic equilibration of dislocations in Harper-Dorn creep. It was assumed that a steady dislocation density was attained when the stress due to the mutual interaction of dislocations was in balance not only with the applied stress but also with the Peierls stress, which fluctuated (and even changed sign) throughout the crystal lattice. The model predicted that, in the steady state, when the applied stress was greater than the Peierls stress, the dislocation density depended upon the square of the applied stress. However, when the applied stress was lower than the Peierls stress, the dislocation density was determined by the Peierls stress and was thus insensitive to changes in the applied stress. It was found that these predictions were in excellent agreement with available experimental data, and it was concluded that the operation of Harper-Dorn creep at stresses which were lower than the Peierls stress was a result of the dependence of the dislocation density upon the Peierls stress.

J.N.Wang: Philosophical Magazine A, 1995, 71[1], 115-26