Cyclic deformation and fatigue properties of Al-0.7Â wt.% Cu alloy produced by equal channel angular pressing

Fatigue damage behavior of an Al-0.7 wt.% Cu alloy, produced by equal channel angular pressing (ECAP) technique, was investigated under constant plastic strain control. It showed that the Al-0.7 wt.% Cu alloy displayed obvious cyclic softening at all the strain amplitudes. The cyclic softening can be attributed to a combination of higher yield strength and hysteresis energy density than the original material. The plastic deformation was carried out by shear bands at low or medium strain ranges, or by both shear bands and coarse deformation bands at high strain ranges. Consequently, fatigue cracks nucleated either along shear bands or along the coarse deformation bands, depending on the applied strain amplitude.