A simple dislocation model of deformation resistance of ultrafine-grained materials explaining Hall-Petch strengthening and enhanced strain rate sensitivity

作者：Blum W^*; Zeng X H

来源：Acta Materialia, 2009, 57(6): 1966-1974.

DOI：10.1016/j.actamat.2008.12.041

• Ultrafine grains
• Dislocation generation
• Dynamic recovery
• Hall-Petch effect
• Strain rate sensitivity

A model is presented where the properties of ultrafine-grained (UFG) materials are explained in terms of the influence of high-angle boundaries on the rates at which dislocations are stored and recovered at the boundaries. The model reproduces the experimental observations that UFG materials reach a steady state where the deformation resistance is independent of strain. that the strain rate sensitivity, of flow stress is relatively high and that the steady-state flow stress increases inversely with the square root of,rain size. The model results are compared to experimental data for UFG Cu and nanostructured Ni.

• 出版日期2009-4