Development and Refinement of the Recovery-Creep Theory

Abstract

A refined recovery-creep model, which takes into account the variation in strain-hardening and recovery with dislocation density, has been worked out. The model gives a realistic description of the strain/time relationship in the primary- and secondary-creep stages. Furthermore, it gives information about the dislocation-density/time relationship and the constant dislocation density attained in the steady state. The model contains two main constants, A ₀ and B ₀, that define the initial creep rate and the mobility of climbing dislocations. It has been proved that έ _s /A ₀, ρ _s , and ɛ _p (creep rate (έ _s ) and dislocation density in the steady state (ρ _s ), and primary-creep strain (ɛ _p )) can be expressed as simple functions of the ratio B ₀/A ₀. Examples are shown where the agreement between experimental and computed creep values is excellent. Comparisons are made between the strain/time and the dislocation-density/time relationships for the refined recovery-creep model and various approximations of it.