Evaluation of activation parameters by Reed-Hill model

Abstract

Differential strain rate tests have been carried out at different temperatures and at various stages along the stress-strain curve at a given temperature for a series of Ni—Co alloys of varying stacking fault energy (SFE). The thermal stress component has been estimated and apparent activation enthalpies have been determined. The likely reasons for poor applicability of the Reed-Hill approach to modelling flow stress and activation parameters for a low SFE alloy, and its better applicability to the temperature range where thermal obstacles conform to a linear force-displacement relationship, are discussed. A mixed analysis including both the Reed-Hill approach and a conventional method is suggested for the determination of activation parameters using limited experimentation.