Two sets of alloys, Mg-Zn-Ca-xNi (0 ≤ x ≤ 5), have been developed with tunable corrosion and mechanical properties, optimized for fracturing materials. High-zinc artificial aged (T6) Mg-12Zn-0.5Ca-xNi (0 ≤ x ≤ 5) series, featuring a straightforward preparation method and the potential for manufacturing large-scale components, exhibit notable corrosion rates up to 29 mg cm⁻² h⁻¹ at 25 °C and 643 mg cm⁻² h⁻¹ at 93 °C. The high corrosion rate is primary due to the Ni–containing second phases, which intensify the galvanic corrosion that overwhelms their corrosion barrier effect. Low-zinc rolled Mg-1.5Zn-0.2Ca-xNi (0 ≤ x ≤ 5) series, characterizing excellent deformability with an elongation to failure of ~26%, present accelerated corrosion rates up to 34 mg cm⁻² h⁻¹ at 25 °C and 942 mg cm⁻² h⁻¹ at 93 °C. The elimination of corrosion barrier effect via deformation contributes to the further increase of corrosion rate compared to the T6 series. Additionally, Mg-Zn-Ca-xNi (0 ≤ x ≤ 5) alloys exhibit tunable ultimate tensile strengths ranging from ~190 to ~237 MPa, depending on their specific composition. The adjustable corrosion rate and mechanical properties render the Mg-Zn-Ca-xNi (0 ≤ x ≤ 5) alloys suitable for fracturing materials.

In this work, a good balance of strength and ductility (a yield strength of ~185 MPa and a uniform elongation of ~20%) has been obtained in a dilute Mg-1.8Zn-0.3Y-0.3Ca-0.3Zr (wt.%) alloy using hard plate rolling (HPR) followed by annealing, with a low anisotropy in mechanical properties. More importantly, the HPR-annealed alloy shows an excellent formability at the same time, i.e., the index Erichsen (I.E.) value reaches ~7.9 mm (the Erichsen cupping test) at room temperature, which is higher compared with the Mg-1.8Zn-0.3Y-0.3Ca-0.3Zr alloy produced by conventional multi-pass rolling (CR) followed by annealing. The excellent synergy of strength and formability of the HPR-annealed alloy is mainly attributed to a weak elliptical ring texture, as well as finer and denser Zn₂Zr₃ precipitates. The formation of weak elliptical ring texture is related to the preferential co-segregation of Zn and Ca elements at boundaries of basal grains with small misorientation angles during annealing, which inhibits the growth of basal grains and promotes the preferential growth of non-basal grains. At the same time, in comparison with the CR-annealed alloy, the HPR-annealed alloy contains finer and denser Zn₂Zr₃ precipitates that are less likely to become sources of cracks, leading to the higher strength and formability of the HPR-annealed alloy. The results in this work can provide reference for the development of high strength Mg alloy sheets with excellent room temperature formability, which also shed light on mitigating planar anisotropy in mechanical properties for Mg alloy sheets.

Rolled Mg-Al-Sn series alloys generally possess limited formability due to the formation of strong basal texture. Texture weakening is an effective way to enhance formability, but usually accompanied with decreasing strength. In this work, synergistic enhancement of strength and formability is achieved in a Mg-3Al-1Sn-0.5Ca-0.1Sm (ATXS3110) alloy by 0.2 wt.% Mn addition combined with high temperature rolling, exhibiting a high index Erichsen (I.E.) value of ~8.1 mm and near-isotropic mechanical properties. On one hand, after Mn addition, the grain refinement from ~7.6 µm to ~4.1 µm results in suppression of extension twinning, thereby preventing the development of strong basal texture upon stretch forming. On the other hand, trace Mn addition narrows the grain size distribution and promotes the formation of uniform fine grains, which induces homogeneous deformation during stretch forming. Moreover, grain refinement and high-density nano-sized precipitates caused by trace Mn addition increase the strength. This work may provide insights into designing low-cost Mg-Al-Sn series alloys with superior comprehensive mechanical properties for further structural applications.

A novel core-shell structured Al₈Mn₄Y-Al₂Ca phase and controllable solute-segregation are elaborately designed in dilute Mg-0.6Al-0.5Mn-0.1Ca-0.1Y alloy (wt.%), via incomplete peritectic transformation during twin-roll casting. When soaked in 3.5 wt.% NaCl solution, Al₂Ca shell with a low electrochemical potential prevents direct contact of noble Al₈Mn₄Y with Mg matrix, mitigating the micro-galvanic corrosion and meanwhile accelerating the formation of uniform corrosion film. Thereafter, solute (Al, Ca)-segregation motivates the formation of heterogeneous multilayered corrosion product films, enhancing corrosion resistance and even achieving self-healing upon long-term corrosion. Notably, the dilute Mg alloy exhibits a corrosion rate as low as 0.22 ± 0.05 mm·y⁻¹.

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 ~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 ~308 MPa, ~360 MPa and ~13.8%, respectively. It reveals that the high YS is mainly originated from grain boundary strengthening (~212 MPa), followed by dislocation strengthening (~43 MPa) and precipitation hardening (~25 MPa). It is found that a relatively homogeneous fine grain structure containing a large fraction (~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.