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

•Two high-performance long-period stacking ordered Mg–Y–Zn–Al alloys were developed.•Significant increase in strength and hardness of alloys over pure Mg was observed.•The retention of strain despite significant increase in alloy strength was analyzed.•Increase in ignition temperatures of Mg–Y–Zn–Al alloys was reported and analyzed.

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 μm) due to the effect of dynamic recrystallization (DRX) were also observed to co-exist with larger worked grains (⩾20 μm) in the extruded microstructures. Compared to monolithic Mg, significant increase in the microhardness (∼67–88%), tensile yield strength (∼245–290%) and ultimate tensile strength (∼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 °C was achieved in the MgY3.72Zn1.96Al0.45 alloy.

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