Investigation of mechanical properties in cryomilled dispersion strengthened aluminium

Abstract
In the present work dispersion strengthened (DS) commercial pure aluminium (cryomilled) has been studied into further detail with respect to deformation behaviour. During uniaxial tensile straining both deformation temperature and initial applied strain rate have been varied. The present work applied DS aluminium as rolled sheets. A thorough investigation is carried out with respect to grain structure and deformation structure of the cold worked material. The uniaxial tensile straining experiments revealed that the rolled sheet exhibit properties that are usual for this kind of processed material, i.e. good elevated temperature properties. Additionally, the rolled sheet achieved very good ductility for specific test parameters. While dislocation slip was identified as the most important deformation mechanism in the lower temperature regime, in the higher temperature regime the material exhibits a combination between grain boundary sliding and dislocation slip deformation mechanism. For the rolled sheet material, there were indications of dynamic grain growth or grain boundary migration for the specimens exhibiting the highest fracture strains. The latter aspect showed to be dependent on applied strain rate variations and the preprocessing procedure of the material.