A unifying analysis of the microplastic kinetics with the operative plastic potential

Abstract

The studies on the existence of a plastic potential in metal systems pre-dates by decades those of thermally activated flow as elucidated by the seminal work of Basinski in 1959. However, to this date a direct correlation between the microplastic kinetic events which integrally manifests itself as the macroscopically determinable plastic potential has not been made. In this work a trial notion of using the activation volume as the fundamental internal variable results in re-expressing the macroscopic rate of doing work in terms of the work of activation necessary to overcome an internal discrete obstacle to dislocation passage. The subsequent differentiation results in a rate of power dissipation relation which under strict conditions of constant-strain-rate sensitivity is only dependent on the square of the strain rate and a linear work-hardening coefficient. On the other hand, if the time dependences of the internal parameters are considered, the power dissipation rate becomes a function of not only the strain rate but also the microstructural evolutionary parameters. The examinations of these predictions suggest means of materials characterization to assess which alloy heat treatment will enhance greater ductility.