The relationship between dislocation recovery creep and vacancy diffusion creep

Abstract

Dislocation recovery creep and vacancy diffusion creep are generally considered to be independent deformation mechanisms, such that both operate at all stress levels. Diffusional creep has a lower stress dependence and it has been reasoned that it therefore gives the greatest contribution at low stress levels.

In this note it is shown that diffusional creep may be considerd to be simply an asymptotic limit of dislocation creep, when the mean dislocation network spacing approaches the polycrystalline grain size at low stress levels.

The role of short-circuiting diffusion along dislocations during recovery creep and along grain boundaries during diffusional creep is arrived at in a natural and self-consistent way.