Abstract
It has become common to represent different creep mechanisms as areas on ‘maps’ with sharp boundaries delineating such areas and indicating the conditions of predominance of each mechanism. These boundaries represent transition stages and the present contribution attempts to clarify the nature of the transition between dislocation and diffusion creep. It is concluded that dislocation- and diffusion-creep mechanisms may occur simultaneously over a wide range of strain rate, but in distinct regions of each grain, and that the form and extent of their individual contributions when combined in a physically plausible manner lead to a gradual change in stress exponent. Two consequences arising from this approach are that new methods of extrapolation of creep data become apparent and that the relative contributions of dislocation and diffusion creep may conceivably be identified by the regions which become free of particles in certain materials.