Synergistic control of texture and strength-ductility balance in extruded dual-phase Mg-Li alloys via Al-mediated precipitation and dynamic recrystallization

Dual-phase Mg-8Li alloys offer lightweight potential, yet the effect of Al content on extrusion-driven microstructure, texture and mechanical response remains unclear. This study varies Al content in Mg-8Li alloys and combines hot extrusion with microstructure characterization and mechanical testing to uncover governing mechanisms. Increasing Al content promotes formation and coarsening of MgLi 2 Al and AlLi precipitates located within the β-Li matrix and at α/β interfaces. These precipitates provide strong Zener pinning and inhibit β-Li recrystallization. β-Li texture is dominated by α and γ fiber components and Al addition increases component number while reducing orientation intensity. α-Mg undergoes dynamic recrystallization (DRX) by twin-induced nucleation and subgrain migration, and continuous dynamic recrystallization (CDRX) completes with 5 wt% Al, producing refined α grains. Competition among basal, prismatic and pyramidal slips generates extrusion-direction and transverse-direction split textures. Aluminum suppresses basal slip and activates non-basal slips, which enhances texture alignment along the normal direction and narrows split angles. Combined effects of nanoscale precipitate pinning, grain refinement and multiple slips activation raise strength by 42% to 282.3 MPa while maintaining 15.6% elongation. Our findings clarify how Al content governs extrusion microstructure-property relations in dual-phase Mg-8Li alloys, guiding composition and processing for high-strength, ductile Mg-Li alloys.