The evolution of damage in perfect-plastic and strain hardening materials processed by equal-channel angular pressing

The evolution of damage was investigated for an aluminum alloy processed by equal-channel angular pressing. The investigation was performed for two different structural states: an annealed condition where there is strain hardening and a processed condition where the strain hardening capability is essentially exhausted and there is a near perfect-plastic behavior. Finite element modeling (FEM) was used with experimental data obtained from tension and compression testing at room temperature. The results show that high levels of damage may be accumulated in the material exhibiting strain hardening behavior and this may lead to billet segmentation whereas in the near perfect-plastic condition cracking occurs only on the upper surfaces of the billets and these cracks are reasonably stable.