Creep behaviors of nanocrystalline copper after stress reduction under nanoindentation at ambient temperature

Abstract

Creep behaviors after the stress reduction tests performed on the nanocrystalline (NC) Cu are studied by the nanoindentation technique at ambient temperature. A composite model based on the iso-strain assumption has been used to reveal the mechanisms behind positive/negative creep behaviors (plastic recovery). Our analysis shows that, distinct creep behaviors in the NC Cu are the results of the competitive deformation mechanisms including dislocation slip forward or backward, dislocations annihilated at grain boundaries (GBs) and GB activities like GB sliding and migration.