Effects of strain on the microstructure–hardness annealing response of highly deformed Al–0·13Mg

Abstract

The robustness of a Hall–Petch dislocation based strengthening model and stereological approach to electron backscatter diffraction (EBSD) microstructure characterisation developed in a previous investigation, was further explored as a function of annealing in aluminium for strains ranging from 3·5 to 20. At the lowest strain, the microstructure was observed to coarsen by conventional recrystallisation, whereas at the two higher strains, this was not observed as coarsening tended to be more homogeneous. The effect of increasing prestrain was observed to increase the rate of softening during annealing. The model was used to predict the proof stress of these materials approximated from hardness data. The results are then critically discussed in terms of the predicted and approximated ‘pseudo’ proof stresses and the nature and limitations of the model parameters. Also a new EBSD mapping approach is proposed to enhance EBSD data quality.