The dislocation-network theory of Harper-Dorn creep was reformulated using a new equation for the kinetics of growth of individual dislocation links in the network. The new kinetic equation has no impact on the scaled differential equation derived previously, which predicts the distribution of link lengths. However, the new theory predicts slightly different behavior for the kinetics of static recovery and leads to a new equation for the strain rate, which was expressed in terms of parameters that could be evaluated independently. This equation was valid not only for steady-state Harper-Dorn creep, but was also valid for primary creep, provided the instantaneous value of the dislocation density was known. Using data on the variation of dislocation density with time, calculated values of the creep rates for Al deformed in the Harper-Dorn regime agree with experimentally measured values to within a factor of 2. Creep curves for Al were calculated with the same degree of accuracy. These calculations involved no adjustable parameters. Steady-state creep rates for many materials presumably deformed in the Harper-Dorn creep regime were compared with the predictions of the new equation for the strain rate. The calculated values agree with experimentally measured data to within a factor of about 150, which compared well with the predictions of other equations proposed in the literature.

Predictive Capabilities of the Dislocation-Network Theory of Harper–Dorn Creep. M.A.Przystupa, A.J.Ardell: Metallurgical and Materials Transactions A, 2002, 33[2], 231-9