Low-Cycle Fatigue Behavior of A11070 Severely Deformed by Equal Channel Angular Pressing Process

摘要

In this paper, the low-cycle fatigue behavior of commercially pure aluminum severely deformed through equal channel angular pressing was studied by the use of data gathered from rotating-bending tests. After designing and manufacturing a suitable die, four passes of severe plastic deformation through strain path B_c were successfully performed on aluminum samples. The annealed and processed samples were then subjected to simple tensile test, Vickers hardness test and rotating-bending fatigue test. The results showed a significant increase in the hardness and yield strength of processed samples but also a significant decrease in their ductility. A simple mathematical analysis was used to calculate the plastic strain applied in the fatigue test, and then the strain-life curves were plotted for the low-cycle region. The plotted strain-life curves showed that, as compared with annealing, the equal channel angular pressing process greatly reduces the transition fatigue life (N_t) of commercially pure aluminum. Examination of Coffin-Manson curves obtained for samples subjected to annealing and severe plastic deformation revealed that equal channel angular pressing has an undesirable effect on the low-cycle fatigue of commercially pure aluminum and decreases the fatigue life in this region.