Effect of homogenization on enhancing the failure strain of high strength quaternary LPSO Mg-Y-Zn-Al alloy

The current work investigates the effect of homogenization on enhancing the failure strain of a high strength MgY1.06Zn0.76Al0.42 (at.%) alloy. Bulk 14H long-period stacking ordered (LPSO) phases (≥10 µm) were progressively broken down into acicular fine platelets (≤2 µm) with increase in homogenization time (1, 2, 4 and 6 hours) at 450 °C. The high density of fine LPSO platelets (≤2 µm inter-particle spacing) were experimentally observed to be more effective than the bulk LPSO phases (≥10 µm inter-phase spacing) in promoting dynamic recyrstallization (DRX) via particle simulated nucleation (PSN) during extrusion which was critical for basal texture weakening to enhance the failure strain of the as-extruded alloy. The alloy homogenized for 2 hours prior to hot extrusion (as-extruded alloy B) displayed the highest tensile yield (376 MPa) and ultimate tensile strength (416 MPa) with significant improvement in failure strain (+80%) compared to as-extruded alloy A (homogenized for 1 hour prior to hot extrusion).