Metadynamic recrystallization in A5083 aluminum alloy with homogenized and as-extruded initial microstructures

Abstract

The static softening behavior of A5083 aluminum alloy with different initial microstructures was studied using various characterization techniques. To calculate the recrystallized fraction, in the compression test, a new method based on the offset yield stress method and the Hall–Petch relationship was proposed, which is more accurate than the conventional methods and applicable even when the initial microstructure is complex. And in the stress relaxation test, a method proposed in our previous study was applied, indicating that this method could be employed in materials with incomplete recrystallization or a complex initial microstructure. Although the as-extruded initial microstructure led to a more developed metadynamic recrystallization, the recrystallization became heterogeneous, compared with the homogenized initial microstructure. When the anvil was not unloaded during the interpass time, the resulting external stress accelerated static recovery but impeded metadynamic recrystallization. New insights were discussed that challenge the conventional view in metadynamic recrystallization. First, metadynamic recrystallization always required an incubation time, unless the experimental conditions were sufficiently favorable for recrystallization. Second, when recovery was active, not only the dynamic recrystallized grains but also the recovery-enhanced subgrains were the potential nuclei for the subsequent metadynamic recrystallization.