Deformation mechanism maps for micro-grained, ultrafine-grained, and nano-grained materials

▶ It is shown that a deformation mechanism map based on grain size can provide an overall presentation of the domains of Coble creep, superplastic flow (micrograin superplastic flow and high-strain rate superplastic flow), and nanograin deformation; and that the boundaries in this map are essentially independent of temperature. ▶ According to the map, triple-junction creep will always predominate at grain sizes smaller than those characterizing Coble creep. ▶ Experimental data reported for nanocrystalline Cu and nanocrystalline Ni along with those available for high-strain rate superplasticity and micrograin superplasticity fall into the correct fields of the map.