Dislocation densities and prevailing slip-sytem types determined by X-ray line profile analysis in a textured AZ31 magnesium alloy deformed at different temperatures

Abstract

Tension experiments were carried out at room temperature, 473 K and 673 K on AZ31-type extruded magnesium alloy samples. The tensile deformation has almost no effect on the typical extrusion texture at any of the investigated temperatures. X-ray diffraction patterns provided by a high-angular-resolution diffractometer were analyzed for the dislocation density and slip activity after deformation to fracture. The diffraction peaks were sorted into two groups corresponding either to the major or to the random texture components in the specimen. The two groups of reflections were evaluated simultaneously as if the two texture components were two different phases. The dislocation densities in the major texture components are found to be always larger than those in the randomly oriented grain populations. The overwhelming fraction of dislocations prevailing in the samples is found to be of < a > type, with a smaller fraction of < c + a >-type dislocations. The fraction of < c >-type dislocations is always obtained to be zero within experimental error.