Large strain work hardening of aluminum alloys and the effect of Mg in solid solution

The work-hardening behavior of a range of aluminum-magnesium alloys, from 0.5 to 4.55 wt pct Mg, is followed up to large strains using compression testing and cold rolling. At large strains, stage IV, an unexpectedly low work-hardening rate of high-Mg alloys is observed, and the work-hardening rate in stage IV is almost unaffected by the Mg content. A model for work hardening is applied and discussed in relation to the experimental observations. Based on microstructural observations of the cold-rolled materials, the low work-hardening rate of high-Mg alloys is ascribed to a different storage pattern of dislocations caused by an increased amount of shear bands and a higher dislocation density inside subgrains.