On the Work-Hardening of AA 3104-H19 Aluminum Alloy

The aim of this study is to investigate the work-hardening of AA 3104-H19 aluminum alloy. Uniaxial tensile tests were carried out in both the rolling and transverse directions. In the past, some authors have used such uniaxial tensile test data and the Hollomon equation fitted to them to predict the forming limit curves. In a previous study, we showed experimentally that the Hollomon equation exponent, typically 0.07, used in such limit strain predictions is too high and should be approximately 0.04. Other authors have obviously used such a high value because they have compensated for the reduction of limit strains near the plane strain by increasing the Hollomon equation exponent. The reduction of limit strains near the plane strain occurs, as the Marciniak-Kuczynski theory, which the aforementioned authors have used, assumes a local inhomogeneity or a thinner section in the sheet to explain the local necking in stretch forming. In this study, it is shown experimentally that the Hollomon equation exponent in both the rolling and transverse directions is very close to 0.04. It is shown further that the Hollomon or Voce equations do not describe very well the work-hardening of the AA 3104-H19 alloy in either the rolling or transverse direction.