DISLOCATION-STRUCTURE DISTRIBUTIONS AND PROPERTIES OF HEAVILY COLD-ROLLED ALUMINUM AND ALUMINUM MAGNESIUM ALLOYS

The microstructural features developed after rolling of aluminum alloys have thoroughly been described in the past by means of transmission electron microscopy. However, with the exclusive use of this technique, it is not possible to ascertain the dislocation distribution and hence the associated modeling of the hardening behavior. In this paper, we show that the simultaneous use of several experimental techniques such as elastic limit, X-ray line broadening and density measurements leads to coherent results pertaining to the dislocations substructures of Al and Al-Mg solid solution alloys. Particularly, with the help of dislocation density determination it was found that the hardening follows a classical rho-1/2 law of the dislocation forest type for most of the strain range. In the cellular regime of pure aluminum, a cell wall hardening mechanism based on an absorption-emission of dislocations holds. A Hall-Petch type law may then be formally followed if a cell wall multiplication with constant dislocation density occurs during rolling.