Strain Hardening Behavior of Ultrafine- Grained Cu by Analyzing the Tensile Stress-Strain Curve

UFG Cu was found to experience two stages of strain hardening processes under uniaxial tensile stress, which was similar to the Stage IV and V of CG Cu after large plastic deformation. The storage of dislocations in small grains and dynamic recovery caused by annihilation of dislocations and GB‐mediated processes were responsible for the different stages of strain hardening behavior. Improvement of strain hardening capability for UFG metals should be based on the mechanisms of strain hardening.