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Herein, novel high‐performance Mg–Al–Sn–Zn–Y (ATZ821−xY) alloys are developed via hard‐plate rolling (HPR). With the addition of Y, the heterogeneous grain structure of the HPRed ATZ821 alloy evolves to be more uniform, accompanied with significant weakening in basal texture. This is due to the faster dynamic recrystallization (DRX) induced by the particle‐stimulated nucleation (PSN) effect from the Al2Y particles, pinning effect from well‐dispersed submicrometer‐sized precipitates including Mg17Al12 and Mg2Sn, and the slips activated by Y atoms in α‐Mg. Correspondingly, the HPRed ATZ821−1.0Y alloy shows a good combination of strength and ductility, that is, a yield strength (YS) of ≈248 MPa, an ultimate tensile strength (UTS) of ≈385 MPa, and a uniform elongation (UE) of ≈20%. The high YS is mainly due to grain boundary strengthening, which accounts for ≈70% of the total YS. The high UE is mainly attributed to the strong work hardening associated with weakened basal texture, well‐dispersed Mg17Al12 and Mg2Sn precipitates, as well as enhanced slips induced by Y atoms in the solid solution. [ABSTRACT FROM AUTHOR]

Calcium (Ca), with abundant and cheap reserves, is a potential element to facilitate the further application of Mg-Al-Sn based alloys. Here, effects of Ca content on the microstructure and tensile properties of Mg-2.0Al-0.8Sn (wt.%) alloys were systematically studied. The experimental results illustrated that the strength, ductility and isotropy of the alloys improved simultaneously with the increase of Ca content. The better ductility and isotropy could be contributed to the weakened texture via particle stimulation nucleation mechanism. The higher strength benefited from the combination of finer grains, more precipitates and residual dislocation density. Eventually, the Mg-2.0Al-0.8Sn-0.5Ca (wt.%) alloy showed the best room-temperature balance of strength and ductility with a yield strength of ∼226.0 MPa, an ultimate tensile strength of ∼282.4 MPa and a fracture elongation of ∼20.2%, which has huge potential as an applicable low-cost high-performance magnesium alloy. [ABSTRACT FROM AUTHOR]

As the applications of heterogeneous materials expand, aluminum laminates of similar materials have attracted much attention due to their greater bonding strength and easier recycling. In this work, an alloy design strategy was developed based on accumulative roll bonding (ARB) to produce laminates from similar materials. Twin roll casting (TRC) sheets of the same composition but different cooling rates were used as the starting materials, and they were roll bonded up to three cycles at varying temperatures. EBSD showed that the two TRC sheets deformed in distinct ways during ARB processes at 300 °C. Major recrystallizations were significant after the first cycle on the thin sheet and after the third cycle on the thick sheet. The sheets were subject to subsequent aging for better mechanical properties. TEM observations showed that the size and distribution of nano-precipitations were different between the two sheet sides. These nano-precipitations were found to significantly promote precipitation strengthening, and such a promotive effect was referred to as hetero-deformation induced (HDI) strengthening. Our work provides a new promising method to prepare laminated heterogeneous materials with similar alloy TRC sheets. [ABSTRACT FROM AUTHOR]

Developing magnesium (Mg) alloys with high strength and ductility at low-cost and high-efficiency is desirable. Achieving a uniform fine grains structure is an effective strategy to enhance the strength and ductility of Mg alloys. In this study, we propose a novel differential-thermal asymmetric extrusion (DAE) method to achieve uniform fine grains during high-speed extrusion. Asymmetric extrusion can introduce additional shear deformation and promote recrystallization. The temperature difference between the billet and the mold can accelerate the cooling rate, thereby inhibiting grain growth. Here, by using DAE, we obtained a uniform fine grains structure with an average grain size of 1.4 μm, and the alloy exhibited a high strength-ductility synergy, with yield strength (YS) of ∼290 MPa and elongation (EL) of ∼18.2 %. The excellent mechanical properties demonstrate the potential of DAE as a low-cost and high-efficiency method for magnesium alloy production. • The Mg-Al-Sn-Ca prepared by DAE exhibit an excellent balance of strength (yield strength: ~290 MPa) and ductility (elongation: ~18.2 %). • The DAE processes transforms the dominant mode of DRX from DDRX to CDRX leading to the formation of uniform fine grain (~1.4 μm) structures. • The large temperature difference between the billet and the mold increases the cooling rate and helps to inhibits the grain growth. [ABSTRACT FROM AUTHOR]

In this work, the quasi-in-situ electron backscattered diffraction (EBSD) is employed to investigate the static recrystallization occurring at the interface of deformation twinning interactions in liquid nitrogen temperature (LNT) rolled AZ61 alloy during electric pulse treatment (EPT). It was found that recrystallization nucleation occurred at the 10 1 ¯ 2 tensile twin (TTW) interaction, after which new grains and part of the original grains consumed 10 1 ¯ 2 TTW and grow up. By contrast, recrystallization nucleation occurs not only at the 10 1 ¯ 1 − 10 1 ¯ 2 double twin (DTW) interactions but also within twin boundaries during subsequent EPT. When multiple twins come into being in the exact grain, the recrystallization growth showed obvious directionality: first, recrystallization grains grow along with 10 1 ¯ 1 − 10 1 ¯ 2 DTW and 10 1 ¯ 1 CTW boundaries and consume them; then the 10 1 ¯ 2 TTWs are consumed and the growth direction of recrystallization grains shifts to along with their boundaries. • Static recrystallization induced by twinning-interactions during electric pulse treatment (EPT) has been investigated. • The effects of twinning-interactions on EPT accelerated recrystallization behaviors have been analyzed. • We suggest an effective way to tailor the microstructure of magnesium alloys by LNT rolling and EPT. [ABSTRACT FROM AUTHOR]

In this work, electrical pulse treatment and isothermal heat treatment are employed to tailor the microstructure of the hot-rolled AZ61 alloy. The influence of pulsed current on the crystal growth mechanism and precipitation phase diffusion was investigated. According to the findings, electrical pulses enhance the recrystallization and dissolution of Mg 17 Al 12 precipitate in hot-rolled AZ61 alloy. The recrystallization fraction of EPTed samples is higher than that of the isothermal HTed counterparts. The amount of Mg 17 Al 12 phase is considerably reduced with the increased EPT duration. In contrast, the Mg 17 Al 12 phase fraction in isothermal HTed samples is just slightly changed. The Nernst–Einstein formula indicates that the electrical pulse effectively improves the total diffusion flux in the diffusion system via the coupling of athermal effect and thermal effect. • The recrystallization process and second phase change of AZ61 alloy under electrical pulse treatment (EPT) were studied. • The effect of second phase dissolution during EPT on the quick recrystallization of hot-rolled AZ61 alloy was studied. • We suggest that a good way to change the microstructure of magnesium alloys is to use EPT to speed up recrystallization. [ABSTRACT FROM AUTHOR]