| Popis: |
The introduction of asymmetric rolling into the thermomechanical processing for an Al-Cu-Mg alloy was demonstrated to produce an excellent combination of strength and ductility. The evolution of the alloy microstructure during this thermomechanical processing was followed carefully using electron microscopy, X-ray diffraction, and atom probe microscopy. The distribution of the Mg and Cu solute atoms, and the characteristic distributions of Mg-Cu co-clusters, were investigated in detail. The factors affecting the strength of the alloy were assessed semi-quantitatively and the results suggest that Mg-Cu atom co-clusters contribute significant strengthening in this Al-Cu-Mg alloy, when subjected to this thermomechanical processing. The novel introduction of asymmetric rolling into the thermomechanical process increases the overall strength and we propose that this is due to the synergistic effects of cluster strengthening, dislocation strengthening, and texture engineering. The significant improvement in plasticity is attributed to a combination of the shear texture, the relatively high ratio of low-angle grain boundaries, and the avoidance of microstructural stress and strain concentrations such as those often associated with precipitation and precipitate-free-zones. |
