A model of creep embodying dislocations whose movements produce work hardening and recovery

Abstract

In conformity with contemporary views, the new model envisages that the initial period of decreasing strain-rate (i.e. primary creep) is due to immobilization of dislocations but it also incorporates the concept of their remobilization by a thermally activated process (such as climb). The resulting creep-equation successfully represents the pattern of behaviour observed when, during an experiment, the stress causing creep is removed, reduced or increased. It correctly simulates the accelerating creep which occurs for a period Δt after the stress has been reduced by Δ[sgrave], mirrors the tendency for Δt to vary with Δ[sgrave] and describes the experimentally observed dependence upon strain-rate and stress of the Baily–Orowan recovery parameter, r(r∼ – Δ[sgrave]/Δt).