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For aluminum laminated composites (ALCs), interlayer bonding strength plays a crucial role in its performance. In this work, 7050/Al/7A52 and 7A62/Al/7A52 ALC were studied to explore the effects of recrystallization and element diffusion on interfacial bonding quality and mechanical properties. The results show that attributed to the deformation localization occurs at the 7A52/pure Al interface, continuous dynamic recrystallization (CDRX), discontinuous dynamic recrystallization (DDRX) and geometric dynamic recrystallization (GDRX) coexist, while only DDRX exists at the bonding interfaces of 7050/pure Al and 7A62/pure Al. Among them, 7A62/pure Al interface has the most obvious element diffusion behavior among the three kinds of interfaces. Notably, recrystallization would have a higher effect on improving bonding quality, which causes the 7A52/pure Al interface of the composites more difficult to delaminate during the tensile test. Besides, the enhancement of element diffusion depth at the 7A62/pure Al interface promotes the bonding strength of 7A62/Al/7A52 ALC to increase by 21.0% compared with that of 7050/Al/7A52 ALC. After the dynamic impact test, the peak flow stress and energy absorption value of 7A62/Al/7A52 ALC reached 567.1 MPa and 72.2 MJ/m3, and the interface remains intact. However, due to the existence of huge strength deviation in the 7A62/pure Al interface, it is more prone to fail during the tensile process, resulting in a decrease in the elongation of the composites. • Systematically investigates the effect of recrystallization and interfacial element diffusion on interface of 7xxx/pure Al. • Recrystallization would have a higher effect on improving bonding quality than element diffusion. • The huge strength deviation would accelerate the failure of bonding interface thus affect the elongation of composites. [ABSTRACT FROM AUTHOR]

With the continuous upgrade of weapons, improving the mechanical properties of 7xxx laminated aluminum alloys for tank armor is a very important task. In this study, the 7B52 laminated aluminum alloy was strengthened through the successive solution treatment, large pre-deformation of 50%, and aging process. The yield strength, ultimate tensile strength, and interlaminar shear bonding strength of this alloy remarkably increased to 558 MPa, 593 MPa, and 93.8 MPa, respectively, which exceeded the values obtained after the traditional solution and aging processes. The effect of the large pre-deformation on the microstructural evolution and mechanical behavior of the 7B52 alloy was examined as well. The mechanical properties depended on the presence of dislocations, low-angle grain boundaries, and tiny precipitates in the alloy structure. The introduction of numerous dislocations and low-angle grain boundaries via large pre-deformation were beneficial for the full precipitation of tiny precipitates during the aging process. According to theoretical calculations, precipitation and dislocation strengthening were the dominant strengthening mechanisms. Moreover, because of its finer grain size, higher dislocation density, and larger number density of precipitates, the 7A62 alloy exhibited higher strength increments than those of the 7A52 alloy after pre-deformation. Therefore, a large pre-deformation may serve as an effective method for improving the mechanical properties of 7xxx laminated aluminum alloys for their application in the military industry. • Large pre-deformation enhances the mechanical properties of 7B52 laminates. • The increase in laminate strength is dominated by precipitation strengthening. • 7A62 alloy shows a higher strength increase after pre-deformation than 7A52 alloy. • Plasticity mismatch promotes the void growth and crack propagation processes. [ABSTRACT FROM AUTHOR]

Lithium-sulfur (Li-S) batteries are regarded as promising high energy density energy storage devices, but their commercial applications are limited due to the poor conductivity of sulfur and the harsh shuttle effect of lithium polysulfides (LiPSs). Herein, nickel-embedded porous carbon materials (Ni/PC) with high electrical conductivity, abundant pores and large space for storage of sulfur were synthesized by instantaneous expansion, nickel salt treatment and high-temperature calcination using corn kernels as precursors. According to the electrochemical results of the designed sulfur-carbon (S@Ni/PC) composite cathode, it delivers a high initial capacity of 1100 mAh·g−1 at 0.5 C as well as maintaining a capacity of 579.3 mAh·g−1 after 500 cycles with coulombic efficiency close to 100%, while the pure sulfur cathode can only remain 143.9 mAh·g−1. Furthermore, the rate performance test displays that a high reversible capacity of 1189 mAh·g−1 can still be maintained when returning to 0.1 C after different current densities, which is nearly 643.5 mAh·g−1 higher than the PC cathode. Such excellent electrochemical performance benefits from the synergistic effect of the interconnected porous structure and polar Ni nanoparticles (NPs). On the one hand, porous carbon materials provide large space for efficiently immobilizing sulfur, and the staggered pores physically hinder the diffusion of lithium polysulfides (LiPSs). On the other hand, in-situ intercalated Ni NPs can both improve electrical conductivity and afford abundant adsorption sites for chemically anchoring LiPSs to suppress shuttle effect. This work reports a facile and useful strategy for the application of biomass carbon in Li-S batteries. • The carbon materials produce abundant porous by the etching of nickel nanoparticles reduced during calcination. • Biomass-derived carbon materials provide a large specific surface area and space for sulfur storage. • Nickel nanoparticles provide adsorption sites for polysulfides and facilitate the catalytic conversion of polysulfides. • The porous structure and polar nickel nanoparticles work together to improve the electrochemical performance of the battery. [ABSTRACT FROM AUTHOR]

In this work, nitrogen-doped bamboo-structure carbon nanotubes (BCNTs) with large diameters (ranging from 50 nm to 300 nm), high specific surface area (437.41 m2·g−1) and thin tube wall (less than 8 carbon layers) were prepared as sulfur host for lithium-sulfur (Li-S) batteries. Sulfur nanoparticles (NPs) with diameters of 20–30 nm were in-situ synthesized on the surface of BCNTs by a facile ultrasonic treatment, which can enhance the binding ability between sulfur and carbon, and then improve the utilization of sulfur. It is found that the in-situ synthesized S@BCNTs composite cathode with a high sulfur content of 62.2 wt% exhibits an initial specific capacity of 1008.4 mAh·g−1 at a current density of 0.1 C, and can still maintain a capacity of 383.9 mAh·g−1 after 500 cycles. Careful composition and microstructure analyses reveal that these excellent electrochemical performance can be ascribed to the synergistic effect of conductive nitrogen doping (especially pyridinic-N and pyrrolic-N) and homogeneous sulfur coating on the surface of BCNTs, which contributes to accelerating electron transport, adsorbing polysulfides and alleviating the shuttle effect. As a result, the as-prepared nitrogen-doped BCNTs can be pretty promising cathode materials for Li-S batteries. This work can open up a new possibility for the design of stable Li-S cathodes for high-performance batteries. • BCNTs show thin tube wall with only about eight carbon layers. • Nitrogen doping enhances conductivity and inhibits the shuttle effect of Li-S batteries. • The sulfur particles are in-situ synthesized on the surface of BCNTs uniformly. • Nickel particles catalyze the growth of BCNTs and improve the capacity of battery. [ABSTRACT FROM AUTHOR]

Ag 3 PO 4 and Ag 3 PO 4 /g-C 3 N 4 were successfully synthesized by an in-situ solvothermal method using graphitic carbon nitride obtained by sectional heating of guanidine carbonate and AgNO 3 as starting materials. The composites were characterized by XRD, SEM, PL, DRS and BET. The photocatalytic performance was determined by deNOx reaction under different light wavelength irradiation. Ag 3 PO 4 /g-C 3 N 4 composites with different ratio showed different band gap and morphology, and also decreased the photo-corrosion and self-corrosion by forming heterojunction. The photocatalytic deNOx ability of Ag 3 PO 4 /20%g-C 3 N 4 was 15.52% under irradiation of visible light (>400 nm) and could be enhanced to 41.76% under irradiation of 290 nm. With the increment of the g-C 3 N 4 content, high efficiency of charge separation induced by the formation of heterojunction between Ag 3 PO 4 and g-C 3 N 4 . [ABSTRACT FROM AUTHOR]

The microstructural stability of aluminum alloy hemispherical components in gyroscope navigation systems is the determinant for navigation precision. In this work, a thermal-cold cycling treatment (TCT) was applied to evaluate the microstructural stability of the hemispherical components. The results showed that the dislocations and precipitation of Al 2 CuMg in the component annihilated with the increasing TCT cycles, improving the microstructural stability. After 16 cycles, the dislocation density reached the minimum value of ∼1.51 × 1014 m−2 in the die fillet area (DFA), indicating an earlier stabilization than that in the bottom of the hemisphere (BOH) after 38 cycles. Such a difference was mainly attributed to the initial dislocation density. The high initial dislocation density in the DFA reduced the nucleation work and diffusion activation energy, which accelerated the nucleation of Al 2 CuMg phases, thereby reducing the stored energy and lattice distortion remarkably. Additionally, the high initial dislocation density increased the superimposed effect of two dislocations of opposite signs, accelerating the annihilation of dislocations. The annihilation of dislocations and precipitation of tiny Al 2 CuMg phases contributed to the optimized microstructural stability. In this sense, the TCT may serve as an effective method for the fabrication of aluminum alloy components with high stability for gyroscopes. [Display omitted] • Al 2 CuMg phase and dislocation are main factors affecting microstructural stability. • The TCT can improve N ̇ of Al 2 CuMg phase due to the decrease of Δ G k and Δ G A. • The initial nonuniform distribution of dislocation can be rebalanced by TCT. • Annihilation of dislocation and increase of N ̇ optimize the microstructural stability. • TCT is an effective method to improve the microstructural stability of hemisphere. [ABSTRACT FROM AUTHOR]

An investigation of the quantitative effect of the deformation process on the deformation mode, texture evolution, and their internal relationship could help control the mechanical properties of targeted materials. In this study, the deformation mechanism and texture evolution of pre-twinning AZ31 magnesium alloy under medium temperature with high-speed impact loading are investigated through electron backscattered diffraction and the coupled simulation of the finite element method and viscoplastic self-consistent models. Basal and < c + a > pyramidal slips are the dominant accommodation modes. The activation of nonbasal slip is promoted, and the number of twins increase with an increase in the impact pressure, leading to a decrease in the relative activity of the basal slip. Based on typical grain rotation statistics, the effects of basal slip, pyramidal slip, and extension twins on grain rotation are studied. With an increase in the pressure, the relative activity difference between the basal slip and pyramidal glide decreases, which is beneficial for the formation of a double-peak basal texture and the enhancement of the intensity of the double-peak texture. The twin density affects the split angle between the double peaks. • Texture evolution during impacting loading were quantitatively unmasked by FEM-VPSC. • Effect of slip system on grain rotation is studied by tracking the rotation route of grain. • Texture is affected by the relative activity difference between basal and pyramidal slips. [ABSTRACT FROM AUTHOR]

The compression behavior and mechanical properties of the Mg-6.9Gd-3.2Y-1.5Zn-0.5Zr (wt.%) alloy filled with intragranular long-period stacking ordered (LPSO) phases were investigated. This alloy possesses a high activation energy of ∼359 kJ/mol, because intragranular LPSO phases inhibit the lattice rotation of α-Mg matrix and may provide back stress. Compression temperature and strain rate (i.e. Zener-Hollomon parameters) combine to influence the DRX (ratio and grain size), workability, and mechanical properties, while the effect of strain rate on the DRX-ed grain size may be reduced at the compression temperature of 450 °C. The alloy compressed at 420 °C and 0.002 s −1 exhibits the superior strength because of the finer DRX-ed grain size, larger number of dynamic precipitates and kink bands. However, dynamic precipitates deteriorate the ductility and workability. [ABSTRACT FROM AUTHOR]

Al-Cu-Mg alloys are widely utilized as a key component of gyroscope navigation systems, since their dimensional stability under different service environments (e.g., thermal or magnetic fields) is the determinant factor for reliable navigation. In this work, a preliminary treatment under the coupling of thermal-magnetic fields was applied to optimize the dimensional stability of the alloy by tailoring the microstructural defects and second phases. A lower thermal strain value of ∼1.58 × 10–3 was rapidly achieved after 6 h by high-efficiency thermal-magnetic treatments (523 K and B = 0.3 T), in comparison with ∼1.67 × 10–3 by thermal treatment. The dimensional variation was mainly attributed to the dislocation density, volume fraction and shape of the Al 2 CuMg phase. Furthermore, the nucleation rate of Al 2 CuMg phases and the annihilation of dislocations were promoted under the coupling effect of the thermal-magnetic treatments. These microstructural evolutions accelerated the reduction of the stored energy and lattice distortion, therefore rapidly decreasing the thermal strain. As a result, a thermal-magnetic field treatment may serve as an effective method to improve the dimensional stability of Al-Cu-Mg alloys for further application in the field of space exploration. [Display omitted] • In comparison with TT, lower thermal strain can be achieved by TMTs (523 K, 0.3 T). • The magnetic field improved N ̇ due to the increase of v and the decrease of Δ G A. • Annihilation of dislocation is promoted due to the mobility of defects induced by TMT. • The promotion of N ̇ and dislocation annihilation improved the dimensional stability. • TMT process can be proposed to improve the dimensional stability of Al-Cu-Mg alloy. [ABSTRACT FROM AUTHOR]