Variations in microstructure and bending formability of extruded Mg-Al-Zn-Ca-Y-MM alloy with precompression and subsequent annealing treatment conditions

In this study, the bending formability of an extruded Mg-9Al-1Zn-0.3Mn-0.9Ca-0.6Y-0.5 MM (AZXWMM91100, wt%) alloy at room temperature is significantly improved through application of a combined precompression and subsequent annealing (PCA) treatment. As the amount of precompression applied along the extrusion direction (ED) (i.e., the total strain) increases from 4% to 6%, the area fraction of ED-oriented grains of the PCA-treated alloy increases, which consequently causes an improvement in its bending formability because these grains accommodate larger tensile strain along the ED during bending. As the temperature of the subsequent annealing treatment increases from 350 degrees C to 450 degrees C, both the area fraction of the ED-oriented grains and the average grain size increase, and the residual dislocation density decreases owing to the promotion of boundary migration and occurrence of the recovery process at higher temperatures. Consequently, the bending formability of both the 4%-precompressed and the 6%-precompressed samples increases with an increase in the annealing temperature. However, when the precompressed samples are annealed at 300 degrees C, their bending formability is lower than that of the extruded alloy because the dislocations formed by precompression remain even after the subsequent annealing at this temperature.(c) 2021 Chongqing University. Publishing services provided by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ ) Peer review under responsibility of Chongqing University

Automated summary

The bending formability of an extruded Mg-9Al-1Zn-0.3Mn-0.9Ca-0.6Y-0.5 MM alloy at room temperature is significantly improved through a combined precompression and subsequent annealing treatment. Increasing the precompression amount and annealing temperature enhances the bending formability of the alloy.