Development of high-performance quaternary LPSO Mg-Y-Zn-Al alloys by Disintegrated Melt Deposition technique

In the present study, new quaternary MgY1.65Zn0.74Al0.53 and MgY3.72Zn1.96Al0.45 alloys (wt.%) were synthesized employing the Disintegrated Melt Deposition (DMD) casting technique followed by hot extrusion. Microstructural characterization revealed the presence of 14H long-period stacking ordered structure (LPSO) and Mg4Y2ZnAl3 phases aligned along the direction of extrusion in both alloys. Refined grains (<= 5 mu m) due to the effect of dynamic recrystallization (DRX) were also observed to co-exist with larger worked grains (>= 20 mu m) in the extruded microstructures. Compared to monolithic Mg, significant increase in the microhardness (similar to 67-88%), tensile yield strength (similar to 245-290%) and ultimate tensile strength (similar to 113-144%) were observed in the Mg-Y-Zn-Al alloys. Despite the significant increase in strength of materials, failure strains of both Mg-Y-Zn-Al alloys were comparable to monolithic Mg. Ignition temperatures of both Mg-Y-Zn-Al alloys were found to outperform commercially available AZ31, AZ80 and WE43 (high-temperature) Mg alloys, and the highest ignition temperature of 770 degrees C was achieved in the MgY3.72Zn1.96Al0.45 alloy. (C) 2015 Elsevier Ltd. All rights reserved.