Improving strength and ductility of Mg-Gd-Y-Zn-Zr alloy simultaneously via extrusion, hot rolling and ageing

An ultra-high strength and high ductility Mg-8.2Gd-3.8Y-1.0Zn-0.4Zr Mg alloy sheet was fabricated by vertical direct chill casting, extrusion, hot rolling and peak-ageing treatment. The peak-aged sheet shows tensile yield strength of 416 MPa, ultimate tensile strength of 505 MPa and superior elongation to failure of 12.8% at ambient temperature. The remarkable improvement of strength is ascribed to the fine β′ phase precipitated within the grains, grains with strong basal texture and the dispersed long period stacking ordered (LPSO) phases located at the grain boundaries.