A rolled Mg-8Al-0.5Zn-0.8Ce alloy with high strength-ductility synergy via engineering high-density low angle boundaries

Developing low-cost rolled Mg alloys with both high strength and ductility is desirable, while the improved strength is generally accompanied with decreased ductility. Here, by using rotated hard-plate rolling (RHPR) with a total thickness reduction of similar to 85%, we obtained a Mg-8Al-0.5Zn-0.8Ce (wt.%, AZ80-0.8Ce) alloy with a high strength-ductility synergy, i.e., the yield strength (YS), ultimate tensile strength (UTS) and elongation-to-failure (EF) are similar to 308 MPa, similar to 360 MPa and similar to 13.8%, respectively. It reveals that the high YS is mainly originated from grain boundary strengthening (similar to 212 MPa), followed by dislocation strengthening (similar to 43 MPa) and precipitation hardening (similar to 25 MPa). It is found that a relatively homogeneous fine grain structure containing a large fraction (similar to 62%) of low angle boundaries (LABs) is achieved in the RHPRed alloy, which is benefit for the high tensile EF value. It demonstrates that LABs have important contributions to strengthening and homogenizing tensile deformation process, leading to the simultaneous high strength and high EF. Our work provides a new insight for fabrication of low-cost high performance Mg alloys with an excellent strength-ductility synergy. (C) 2022 Chongqing University. Publishing services provided by Elsevier B.V. on behalf of KeAi Communications Co. Ltd.