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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]

Highlights: [•] We proposed two constitutive equations with varying parameters. [•] The phenomenological equation has high accuracy in a local range. [•] The empirical equation has higher accuracy in a wide range. [•] The two equations have a good ability to model superplastic flow behavior. [Copyright &y& Elsevier]

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]

During air bending of sheet metals, the correction of punch stroke for springback control is always implemented through repeated trial bending until achieving the forming accuracy of bending parts. In this study, a modelling method for correction of punch stroke is presented for guiding trial bending based on a data-driven technique. Firstly, the big data for the model are mainly generated from a large number of finite element simulations, considering many variables, e.g., material parameters, dimensions of V-dies and blanks, and processing parameters. Based on the big data, two punch stroke correction models are developed via neural network and dimensional analysis, respectively. The analytic comparison shows that the neural network model is more suitable for guiding trial bending of sheet metals than the dimensional analysis model, which has mechanical significance. The actual trial bending tests prove that the neural-network-based punch stroke correction model presents great versatility and accuracy in the guidance of trial bending, leading to a reduction in the number of trial bends and an improvement in the production efficiency of air bending. [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]