The effect of unloading time on the interrupted creep behaviour of pol
ycrystalline copper specimens was investigated over the temperature ra
nge 298-773 K. Up to 553 K, cyclic creep acceleration could be explain
ed in terms of deformation and hardening using a dislocation glide mod
el with recovery during unloading being due to dislocation climb. At h
igher temperatures, recrystallisation effects probably influence behav
iour.