It was recalled that the dynamic internal variables which controlled plastic flow could be assessed only by dynamic materials testing. The testing method preferred here was precision strain-rate sensitivity, in which the change in flow stress due to a given change in strain-rate was taken to be a measure of the product of the activation volume and the flow stress (activation work). From the work-hardening slope, a model parameter which was proportional to the mean slip distance, λ, was simultaneously determined. The deviation from the linear Cottrell-Stokes relation as determined with the Haasen plot

indicated the evolution of secondary defects other than monopole dislocations. Hence PSRS could assess the theoretical predictions of the activation distance, d, and work as a function of temperature, resulting in quantitative values that were in accord with dislocation theory at temperatures below that where point defects became mobile. A method to calibrate λ using Stage II slope θII showed that λ/l, where l was the mean forest dislocation spacing, was inversely proportional to θ, the work hardening coefficient. This analysis has led to a new plot of θII/θ versus b2λ/ν where b was the Burgers vector and its slope was directly proportional to d. An example using an alumina-dispersed high-conductivity Cu showed that geometrically necessary punched out loops were continuously generated. The role of point defect mobility was dramatically illustrated by load drops in [001] Al crystals with the formation of slip clusters.

Dynamic Dislocation-Defect Analysis. S.Saimoto: Philosophical Magazine, 2006, 86[27], 4213-33