Work hardening behavior of aluminum over a wide range of strain

The work hardening behavior of high purity (4N) aluminum was investigated over a wide range of strain. The true stress-true strain curves of both annealed and equal-channel angular pressed (ECAP) Al samples were analyzed mathematically after deformation in tensile and compression tests. In this analysis, the absolute strain calculated from the annealed state was used where the annealed state relates to zero strain and the ECAP samples have an imposed strain before subsequent deformation in tensile or compression testing. The results show that in the range of low strains, as in the deformation of annealed samples, the rate of hardening is always positive and the magnitude of the hardening rate decreases monotonously with the total strain. In the range of high strains, as in the samples subjected to ECAP, the yield stress saturates because a homogeneous microstructure is ultimately established through ECAP processing.