On the cyclic behaviour of ultra-fine grained copper produced by equi-channel angular pressing

摘要

The cyclic response of ultra-fine grained (UFG) copper produced by equi-channel angular exrusion (ECAE) is investigated under plastic strain or load control with the aim of 1) understanding of cyclic softening/non-softening via examination of s tructural changes during fatigue; 2) comparison of fatigue prpperties of materials with different intial UFG structure; 3) comparison of fatigue properties of UFG and coarse-grained materoas. The cyclic behaviour appears to be strongly dependent on the fine-grain structure achieved during processing. Under the same testing conditions, the samples having different initial UFG structures may either soften or not. It is shown that partial recrystallization and grain growth can occur during cyclic deformation of UFG copper, resulting in rapid softening.