Indexed on: 25 Jul '16Published on: 22 Jul '16Published in: Materials & Design
The effects of the Li addition on the microstructure evolution of Mg94-xY4Zn2Lix (at.%, x = 0, 1, 5, 9 and 13) alloys were systematically investigated. Little Li (< 1 at.%) addition facilitated the formation of 18R LPSO phases, but exceeded Li (> 1 at.%) addition inhibited the precipitation of 18R LPSO phases. While the (Mg, Zn)24Y5 eutectic phases increased gradually with the addition of Li. Microstructural refinement was significant when the content of Li was 5 at.%. Li addition also changed the formation behavior of 14H LPSO phase of solid-solution Mg89Y4Zn2Li5 alloy only containing α-Mg and LPSO phases. The ultimate tensile strength and elongation of as-extruded Mg89Y4Zn2Li5 alloy reached to 385 MPa and 14%, respectively. The coexistence of kinky block 18R LPSO phases and fine dynamical recrystallized (DRXed) grains surrounding bent lamellar 14H LPSO phases was responsible for the excellent mechanical properties.