Developing 500 MPa-grade heterogeneous-structured Mg sheets via tailoring ultrafine grains and high-density precipitation

It remains a great challenge in producing magnesium alloy sheets with yield strength (YS) exceeding 500 MPa. Here, we innovatively integrated pre-aging with hard-plate rolling (PA-HPR) in a Mg-Gd-Y-Zn-Mn alloy, achieving ultra-high YS of 521 MPa, tensile strength of 540 MPa, with an adequate ductility of 4%. The pre-aged coherent γ′ precipitates effectively promote dynamic recrystallization by accelerating high-angle grain boundaries formation in HPR, resulting in high-fraction ultrafine grains. The final aging leads to precipitates of high-density γ′ and β′, further elevating strength. This work demonstrates an efficient methodology for preparing ultra-strong magnesium alloy sheets via pre-aging combined with large-thickness-reduction rolling.