Ultra high-strength Mg–Gd–Y–Zn–Zr alloy sheets processed by large-strain hot rolling and ageing

Ultra high-strength Mg–8.2Gd–3.8Y–1.0Zn–0.4Zr alloy sheet was prepared by large-strain hot rolling and subsequent ageing process. The sheet exhibits excellent tensile properties at ambient temperature with ultimate tensile strength of 517 MPa, 0.2% proof stress of 426 MPa and elongation to failure of 4.5%. The notable improvement in strength is attributed to the dense distribution of the fine precipitates inside the grains, scattered precipitates at the grain boundaries, bimodal grain size distribution with fine recrystallized grains and large deformed grains with intense basal texture.

► Mg–8.2Gd–3.8Y–1Zn–0.4Zr alloy was severely hot rolled with total 96% reduction and aged. ► The sheet exhibits ultra-high strength of 517 MPa with elongation to failure of 4.5%. ► Dense nano β′ phase play a key role in the age hardening of the sheet. ► The deformed grains with a strong basal texture and LPSO phase strengthen the alloy. ► The recrystallized grains with weak texture improve ductility.