Novel flow stress prediction and work hardening behavior of aluminium alloy AA7075 at room and elevated temperatures

Abstract

The strength and deformation behavior of the aluminium alloy AA7075 was crucial information for engineering and manufacturing design. Tensile tests were performed in a temperature range of 25–300 °C on the aluminium alloy AA7075-T651. Flow curves at different temperatures were shown. The work hardening behavior was analyzed using the Kocks-Mecking and Crussard-Jaoul models. Flow curves in hardening regimes were predicted using constitutive models, i.e., Hollomon, Ludwigson, Ludwik, Swift, and Voce. At high temperatures involved with softening phenomenon, Voce model combined with linear softening or Voce softening were used to predict flow stresses. A novel approach, Voce hardening and softening models combined with the piecewise nonlinear regression technique, was introduced. It was found that the plastic deformation of aluminium alloy AA7075 was dominated by only one mechanism indicated by one slope of stage III in the K-M plot. The hardening regime was found at room and elevated temperatures and could be predicted reasonably using all constitutive equations. At elevated temperatures, the novel approach predicted flow stresses with great accuracy.