Quasi-in-situ EBSD Study of the Microstructure and Texture Evolution During Static Recrystallization in an Extruded Mg-Mn-Ce Alloy

Abstract

A quasi-in-situ electron backscatter diffraction (EBSD) technique is used to study the microstructure and texture evolution in an extruded Mg-1Mn-0.2Ce (wt.%) alloy during annealing at 400°C. The as-extruded alloy has a bimodal and partially recrystallized microstructure with a strong [10 1 ¯ 0]//ED basal texture (ED represents extrusion direction). Upon annealing, the strong [10 1 ¯ 0]//ED texture is mitigated and gradually replaced by a major rare earth (RE)-texture and minor texture components lying within an arc between [10 1 ¯ 0]//ED and [11 2 ¯ 0] //ED. The RE-texture component observed from localized quasi-in-situ EBSD of a randomly selected area is [85 13 ¯ 6] //ED, which is ~8.1° from the [44 8 ¯ 3]//ED RE-texture observed in the bulk sample. The texture change during quasi-in-situ annealing is associated with the preferential growth of the recrystallized (RX-ed) grains whose orientations are near [85 13 ¯ 6] //ED and [32 5 ¯ 0] //ED, at the expense of both RX-ed and deformed grains with [10 1 ¯ 0]//ED orientations. This grain growth process mainly occurs in the deformation bands, where there is an agglomeration of the basal and/or pyramidal II geometrically necessary dislocations (GNDs). The observed preferential grain growth could be due to the relatively low energy stored in these RX-ed grains that have specific orientations.