A comparison between DCCAE and conventional extrusion of Mg-9.5Li-3Al-1.6Y alloy

Double change channel angular extrusion (DCCAE) was performed in dual-phase Mg-9.5Li-3Al-1.6Y (wt.%) alloy to develop fine-grained microstructures. The microstructure evolution during DCCAE and conventional extrusion (CE) was investigated. The microstructure of the extruded dual-phase Mg-Li alloy consisted of recrystallized β-Li grains, banded α-Mg phases, and Al2Y phases distributed in β-Li phases and phase-interface uniformly. Compared with CE, the specimens after DCCAE had smaller β-Li grain size (3–5 μm by the DCCAE and 6–10 μm by the CE) and the α-Mg phases were refined during the DCCAE. The distribution of the Al2Y phases was improved a lot by DCCAE. Furthermore, the specimens after DCCAE had better tensile strength than conventional extrusion ones.

TEM images of the Mg-9.5Li-3Al-1.6Y alloy(a) Dynamic recrystallized β-Li grains by CE; (b) Al2Y distributed at β-Li grains boundaries after DCCAE; (c) Al2Y distributed in β-Li grains after DCCAE; (d) Dislocations in α-Mg phase after DCCAEFigure optionsDownload full-size imageDownload as PowerPoint slide