Effect of Cross-Channel Die Configuration on the Stress–Strain State During Cyclic Pressing with Alternating Deformation Directions

This study investigates the effect of die geometry on the deformation behavior of a disc-shaped billet during cyclic pressing with alternating deformation directions. Each complete cycle comprised two successive passes with a 90° change in the pressing direction. Two cross-channel die configurations were considered: aligned and offset channels. Numerical simulations were performed in DEFORM-3D using the built-in material model for AA5049 aluminum alloy. After one pressing cycle, the offset-channel die resulted in a greater accumulation of equivalent strain: the proportion of the analyzed cross-section with strain values above 0.15 mm/mm increased from 36.78 to 53.80%, while the proportion of regions with values above 0.30 mm/mm increased from 13.43 to 21.08%. Effective stress levels remained comparable for both configurations, whereas offset channels increased the proportion of material subjected to compressive mean stresses. AA3003 aluminum alloy was used for experimental investigation of the structural effects of changes in die geometry, with particular attention to the evolution of the deformation substructure during plastic deformation. Specimens subjected to ten deformation cycles were examined by transmission electron microscopy. The selected TEM regions showed geometry-dependent differences in cell/subgrain morphology and substructure fragmentation. The characteristic cell/subgrain dimensions were 0.476 ± 0.027 µm for aligned channels and 0.457 ± 0.014 µm for offset channels. Because the uncertainty intervals overlap and no significance test was performed, these values are not interpreted as evidence of a statistically significant size difference. The results demonstrate that channel geometry affects the strain and stress distributions as well as the formation of the deformation substructure. Given the differences in alloy composition and number of deformation cycles, the numerical and experimental results were compared qualitatively.