Ultrafine-Grained Magnesium Alloys Manufactured by Multi-axial Forging: Elucidating Mechanisms of Achieving Both High Strength and High Ductility

Warm processingProcessing of magnesium (Mg) alloysMagnesium alloys (Mg alloys) is a challenge because Mg has a hexagonal close-packed (HCP) lattice with limited slip systems, which makes it difficult to plastically deform at low temperature. To address this challenge, a concept of combining annealing of as-cast alloy and multi-axial forgingMulti-Axial Forging (MAF) was adopted for Mg alloysMagnesium alloys (Mg alloys) to obtain textureTexture-free ultrafine-grainedUltrafine-grained magnesium alloys (UFG) structure with high strength-high ductility combination. We describe here the initial findings that indicated a distinct and fundamental transition in the deformation behaviorDeformation behavior of low strength coarse-grained (CG) rare earthRare-earth element containing Mg alloy from twinningTwinning to strong and ductile UFG Mg alloyMagnesium alloys (Mg alloys) with basal and pyramidal dislocationDislocation slip. This implied the role of specific grain boundary states (grain boundary character distribution), grain orientation, and dislocation activity in governing the deformation mechanisms.