High-temperature deformation of commercial-purity aluminum

The stress-strain behavior of aluminum 99.5 pct (2–9) purity deformed under hot-working conditions has been found to be satisfactorily described by combining the exponential saturation equation earlier proposed by Voce and a latter model advanced by Kocks. Voce’s equation describes the strain dependence of the flow stress, whereas the temperature and strain rate dependencies of both the initial flow stress and the saturation or steady-state stress are introduced by means of Kocks’ model, which leads to the definition of a different temperature-compensated strain rate parameter. The basic principles of the dynamic materials model (DMM) advanced by Gegel and co-workers has been reassessed, leading to a different proposition in relation to the calculation of both the power dissipator co-content (J) and the power dissipation efficiency (η), which makes use of the constitutive equation previously developed. Such concepts are later applied to the analysis of a typical industrial hot-rolling process conducted on commercial-purity aluminum. From the microstructural point of view, hot rolling of commercial-purity aluminum has been found to be conducted under conditions of relatively low power dissipation efficiency (η ≈ 0.20 to 0.25), which is likely to be associated with the predominance of dynamic recovery as the main dislocation rearrangement mechanism.