The structure and properties of some heavily cold worked aluminum alloys

Influence of Residual Stress around Constituent Particles on Recrystallization and Grain Growth in Al-Mn-Based Alloy during Annealing

Effect of the residual stress on the recovery and recrystallization behaviors of the cold-rolled AA3003 aluminum alloy was investigated. The evolution of deformed microstructure and dislocation density characterized by TEM and Synchrotron X-ray measurements found that the change in the ratio between low angle grain boundaries (LAGBs) and high angle grain boundaries (HAGBs) during annealing is varied depending on the initial dislocation density, where the value of HAGB/LAGBs ratio is amounted to be about 0.8 at maximum. The nucleation and growth rate of the recrystallized grains are strongly dependent on the net driving pressure associated with dislocation density increased by the amount of reduction. EBSD analysis revealed that the deformed zone composed of the fine equi-axed grains with large misorientation angles would be formed in the vicinity of the constituent particles, which is consistent with the region of the large residual stress and total displacement predicted by Eshelby inhomogeneity problem under cold rolling condition.

EBSD FEG-SEM, TEM and XRD techniques applied to grain study of a commercially pure 1200 aluminum subjected to equal-channel angular-pressing

Microstructural evolution due to equal-channel angular-pressing (ECAP) with increasingly severe deformation was investigated in a commercially pure 1200 aluminum alloy. A true strain of eight produced sub-micrometer scale grains and very fine subgrains in the grain interior. The deformation process was documented and described using field-emission (FEG) gun scanning and transmission electron microscopy techniques. After eight ECAP passes, the high-angle grain boundaries accounted for approximately 70% of all boundaries. The fine spacing resolution of FEG scanning electron microscopy allowed detailed grain and subgrain statistical evaluation in the deformed microstructure; transmission electron microscopic inspection afforded appreciation of the role of very low-angle misorientation boundaries in the microstructure-refining process. ECAP results were compared with those produced by cold rolling. The material's texture evolved in a decreasing trend of Cube {001}100 intensities in favor of Cube rotated toward the normal-to-pressing direction {001}120, while Goss {110}001 and {111}110, {111}112 directions slightly increased with strain.