An Interpretation of Creep Deformation in Alpha-Iron from the Viewpoint of Dynamic Recovery

Abstract

Stress-relaxation and tensile tests have been performed at various creep strains to study the dynamic-recovery and work-hardening behaviour of alpha-iron during creep. The work-hardening rate controls the creep deformation to a minor extent only; the observed creep rates at various stresses and temperatures can be explained mainly in terms of the dynamic-recovery rates in both the paramagnetic and the ferromagnetic temperature regions. The activation energies for dynamic recovery are in good agreement with those for creep, which are equal to the activation energies for self-diffusion. Thus, it is concluded that the creep deformation of alpha-iron is determined by a diffusion-controlled dynamic-recovery process. It is also proposed that the stress-relaxation method should be used in quantitative studies of dynamic recovery during creep.