Three-dimensional characterization of micron second-phases and recrystallized structure in 5083 aluminum alloy

The micro-sized second-phase and recrystallized structure has an important influence on the strength and toughness of 5083-O alloy. In order to acquire the morphological feature of the micro-sized second-phase particles and recrystallized particles in 5083-O alloy， multi-slices EDS data at a low acceleration voltage of 5 kV and EBSD data at 20 kV of the alloy are collected based on the double beam microscope system. These multi-slices data are restructured into three-dimensional types by Avizo software. The size， morphology， distribution， and volume fraction of the chief second-phases （Mg2Si phase and Fe-rich phase） and recrystallized structure are obtained through the restructured data. The results show that the volume fractions of Mg2Si phases， Fe-rich phases， and recrystallized particles in the studied alloy are 0.46%，0.25%， and 11.7%， respectively. Most Mg2Si particles have smooth surfaces， with shapes of near-spherical， near-ellipsoid， or rod-shaped， and elongate along the rolling direction. The Fe-rich phases in the alloy are angular or subangular， and have relatively low spherical degrees. The three-dimensional EBSD restructure data show that the smaller size recrystallized particles have the higher spherical degrees， and the bigger size recrystallized particles have the lower spherical degrees. It is found that the recrystallized grains grow up from the small sphere recrystallized particles during the annealing process， and grow fastest along the rolling direction. The morphology of recrystallized particles is more truly reflected by three-dimensional EBSD results.