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A novel electromagnetic shocking treatment (EST) is put forward to reduce the stress corrosion cracking (SCC) susceptibility of high-strength aluminum alloys and its fasteners by selectively modifying grain boundary (GB) microstructure. The effect of EST on the microstructure, mechanical properties and SCC susceptibility of T73-Al7075 alloy and its high-lock nuts has been investigated. Mechanical properties, electrochemical performance and constant strain SCC test have been carried out for T73-Al7075 alloy, microhardness test and SCC test under wet-dry cyclic condition have been carried out for its high-lock nuts, as well as microstructure characterizations via SEM, EBSD and TEM have been carried out for T73-Al7075 alloy. Comparing to the received sample, the strength of EST sample basically keep consistent while the elongation increases slightly, besides, the electrical conductivity and electrochemical corrosion performance improves. The SCC susceptibility of T73-Al7075 alloy and its high-lock nuts have been reduced after EST. Microstructure characterization shows that the grain morphology and matrix intragranular precipitate distribution of the EST sample keep almost the same as those of the received sample, which is consistent with the almost unchanged mechanical properties of alloy sample. However, EST induces the transformation of grain boundary precipitates (GBPs) and the formation of stripy/wavy GB as observed experimentally, which indicates that EST promotes nonlinear GB wetting or pre-melting and even grain bridging. The phase transformation and GB complexion transition induced by EST are main factors attributing to the obvious improvement of SCC resistance of T73-Al7075 alloy and its high-lock nuts. It can be deduced that anodic dissolution cracking will be relieved because of the dissolution and coarsening of GBPs. Hydrogen induced cracking and crack propagation can be relieved with the occurrence of grain bridging. They are both beneficial to improve SCC resistance of Al7075 alloys. This work provides a novel EST method to targetedly embellish GB microstructure, optimize GB complexion and connectivity, and then enhance the service performance of solid alloys and even finished parts. [Display omitted] • A novel EST is put forward to improve SCC of T73-Al7075 alloys and its fastener. • EST selectively modifies GBs of Al alloy without losing mechanical properties. • EST promotes GB wetting and grain bridging on nanoscale for Al7075 alloy. • EST improves SCC of T73-Al7075 alloys by embellishing GB complexion. [ABSTRACT FROM AUTHOR]

Al-Ti-C master alloys were fabricated by using aluminum melt reaction method with graphite powders (GPs) or carbon nanotubes (CNTs) as carbon source. The microstructure formation during the reaction process was analyzed. The α-Al grain refinement abilities of the master alloys were checked. The results demonstrate that the TiC particles form mainly through the reaction between the solid C (GPs or CNTs) and the solute Ti. Using CNTs as the carbon source can significantly enhance the recovery rate of carbon and promote the formation of Al-Ti-C master alloy with a well dispersed microstructure and high α-Al grain refining ability. [ABSTRACT FROM AUTHOR]

Recently, an efficient integrated forging process has been proposed in which solutionized aluminum alloy extruded bars are directly hot forged and quenched. In this study, the hot deformation behaviors and microstructure evolution of 6082 aluminum alloy extruded bar was investigated via isothermal compression tests under the temperature range of 400–535 ℃ and strain rates range of 0.1–10 s−1 with different strains. The deformation behaviors were described by the established strain-compensated constitutive model and processing maps. The microstructure evolution of the deformed specimens was revealed by electron back scattered diffraction (EBSD) and transmission electron microscopy (TEM). It was found that the Zener-Hollomon (Z) parameter, which involved temperature and strain rate, exerted a considerable influence on the deformation behaviors and microstructure evolution. Deformation-induced extensive dislocations were pinned by the dispersoids and generated cellular substructures under high ln Z (i.e. low temperature or high strain rate), potentially triggering dynamic instability. The tangled dislocations pinned by the insoluble dispersoids continued to overcome the pinning points as ln Z decreased, while the dislocations were consumed by the rotation of subgrain boundaries. As a result, the geometrically necessary dislocation (GND) was decreased with the significant increase of the fraction of high angle grain boundaries (HAGBs). In addition, the stable-end orientations, namely, Brass {011}< 211 > and Goss {011}< 001 > texture components with high Schmid Factors (SFs) are generated during compression, facilitating the dislocation movement and thus promoting the fraction of recrystallization. The above findings demonstrate the foundation for improving forming performance and optimizing the processing parameters for the integrated forging process. • The flow behaviors of solutionzied 6082 aluminum alloy extruded bars were investigated. • The relationship of the dominant softening mechanisms and the Z parameter was revealed. • Evolution of grain boundaries misorientation and geometrically necessary dislocation was illustrated. • The characteristics of grain orientation and Schmid Factors were investigated. [ABSTRACT FROM AUTHOR]

Thin film solar cells based on chalcopyrite Cu(In, Ga)Se 2 (CIGSe) absorber layers were fabricated successfully using a three-stage co-evaporation process. The effects of annealing the (In,Ga) 2 Se 3 (IGSe) precursor layer on the preferred orientation and morphology of the CIGSe films as well as the performance of the Ag/Ni/(Ga,Al):ZnO/i-ZnO/CdS/CIGSe/Mo/Glass cell were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and illuminated J–V and quantum efficiency measurements. Layer studies indicated that the CIGSe film texture changed from (112) to (220) with increasing annealing time. Cell studies showed that the performance of the solar cell was improved with an abrupt change in the open circuit voltage and a remarkable increase in efficiency from 7.35% to 14.35% according to the annealing time in the range, 0–30 min. [ABSTRACT FROM AUTHOR]

Adjusting the electronic and magnetic properties of materials by strain engineering is an effective strategy to improve the performance of electronic and spin electronic devices. In this paper, we study the electronic and magnetic properties of Cr 2 C and Cr 2 CX 2 (X = F, O,OH) under mechanical strain based on density functional theory. In the strain-free state, Cr 2 C and Cr 2 CO 2 are in the ferromagnetic (FM) metallic ground states, while Cr 2 CF 2 and Cr 2 C(OH) 2 are in the antiferromagnetic (AFM) semiconducting states. Applying tensile strain can enhance the magnetic moments of the Cr atoms of all the Cr 2 C and Cr 2 CX 2 (X = F, O, OH) systems. The electronic structure can also be affected with the increase of strain, e.g., resulting in narrowing of the band gap of the AFM semiconducting systems (Cr 2 CF 2 and Cr 2 C(OH) 2) and enhancing the spin-splitting of the FM metallic systems (Cr 2 C and Cr 2 CO 2). The results indicate a possible broadened applicability of strained Cr 2 C-based MXenes in future spintronics. • In the strain-free state, Cr 2 C and Cr 2 CO 2 are in the ferromagnetic (FM) metallic ground states, while Cr 2 CF 2 and Cr 2 C(OH) 2 are in the antiferromagnetic (AFM) semiconducting states. • Applying tensile strain can enhance the magnetic moments of the Cr atoms of all the Cr 2 C and Cr 2 CX 2 (X = F, O, OH) systems. • Applying tensile strain can change the electronic properties and magnetic properties of the system. [ABSTRACT FROM AUTHOR]

Antimony sulfide (Sb 2 S 3) is widely used in photocatalysts and photovoltaic cells because of its abundant reserves, low toxicity, environmental friendliness, narrow band gap, and high light absorption capacity. Sb 2 S 3 shows a quasi-one-dimensional structure composed of [Sb 4 S 6 ] n nanoribbons, a lot of reported studies are focused on preparing Sb 2 S 3 with [hk1] oriented dominant growth to improve the photogenerated carrier transport capacity of Sb 2 S 3. However, there is relatively few research on the preparation of [hk1] oriented rod-like Sb 2 S 3 by vapor transport deposition (VTD) method. In this work, the VTD method was used to prepare Sb 2 S 3 with [hk1] oriented growth on the FTO substrate, and then composite with the ternary solid solution Cd x Zn 1−x S. Finally, a novel Sb 2 S 3 /Cd 0.6 Zn 0.4 S S-scheme heterojunction with rod-like core-shell structure was successfully constructed, which could effectively improve the photoelectrochemical properties. Because the solid solution component x is adjustable, that is, Cd x Zn 1−x S has continuously adjustable band gap width and energy level position, the Sb 2 S 3 /Cd x Zn 1−x S heterojunction type can be regulated from Type-II to S-scheme. Photoelectrochemical (PEC) tests indicated that the composite photoanode Sb 2 S 3 /Cd 0.6 Zn 0.4 S achieved a higher photocurrent density (2.54 mA·cm−2, 1.23 V vs. RHE), which is about 4.31 times that of pure Sb 2 S 3 nanorod photoanode (0.59 mA·cm−2, 1.23 V vs. RHE). • Rod-like Sb 2 S 3 with [hk1] orientation is deposited on FTO substrate by VTD method. • The Sb 2 S 3 /Cd x Zn 1−x S heterojunction type can be regulated from Type-Ⅱ to S-scheme. • The S-scheme heterojunction could effectively promote PEC water splitting. • The photoelectrode exhibits considerable photocurrent 2.54 mA·cm−2 at 1.23 V RHE. [ABSTRACT FROM AUTHOR]

Ni 0.6 Co 0.2 Mn 0.2 (OH) 2 with unique morphology of dispersed hexagonal slab particles is synthesized via the hydrothermal method, which reacts with lithium hydroxide to form single-crystalline LiNi 0.6 Co 0.2 Mn 0.2 O 2 (SC-NCM) after a simple sintering process. Scanning electron microscopy, X-ray diffraction and transmission electron microscopy testify the micrometer-sized SC-NCM particles display well-ordered layered structure with excellent crystallinity. Electrochemical characterization demonstrates that the LiNi 0.6 Co 0.2 Mn 0.2 O 2 sample performs excellent capacity retentions of 93.2% (2.8–4.3 V) and 89.6% (2.8–4.5 V) after 100 cycles at a current rate of 1 C. In particular, LiNi 0.6 Co 0.2 Mn 0.2 O 2 displays extraordinary rate property (174.5 mAh g−1 at 0.1 C and 130.7 mAh g−1 at 5 C). Therefore, it may provide a new method for the preparation of single-crystalline LiNi x Co y Mn z O 2 materials with superior electrochemical performance. • Ni 0.6 Co 0.2 Mn 0.2 (OH) 2 with unique morphology of dispersed hexagonal slab particles is synthesized. • Single-crystalline LiNi 0.6 Co 0.2 Mn 0.2 O 2 is formed after a simple sintering process. • Rate performance is appreciably enhanced. [ABSTRACT FROM AUTHOR]

In this work, polypyrrole (PPy) was in situ polymerized on the surface of TiO 2 nanotube array (TiO 2 NTA, with average pore diameter of 110 nm and length of 490–750 nm) using cyclic voltammetry method to develop the nanocomposite photoelectrode of PPy@TiO 2 NTA. The morphology and the physicochemical properties of the photoelectrode were characterized by SEM, XRD, FTIR, Raman Spectra, and XPS. It was found that the PPy modification enlarged the light adsorption range of the photoelectrode, as well as increased the photocurrent density under UV light irradiation. Furthermore, the performance of PPy@TiO 2 NTA photoelectrode was investigated for the decolorization of methylene blue (MB) by means of photocatalytic (PC), electrocatalytic (EC) and photoelectrocatalytic (PEC) degradation. The decolorization rate of MB using the PPy@TiO 2 NTA increased by 24.94% and 10.85% under PC and EC conditions, respectively, in comparison with the decolorization rate obtained using pristine TiO 2 NTA. The improved decolorization rate of MB was mainly attributed to the separation efficiency of electron-hole pairs originated from TiO 2 , and the enhanced utilization of visible-light due to the presence of PPy. Furthermore, the decolorization rate of MB under the PEC condition was also significantly improved, compared with the sum of the decolorization rate of PC and EC systems, indicating the synergistic effect of MB oxidation in the photoelectrocatalysis. • PPy was synthesized onto TiO 2 nanotube array via cyclic voltammetry to fabricate a p-n junction material as photoelectrode. • PPy can enhance the electrocatalytic efficiency of TiO 2 nanotube array, as well as the photocatalytic efficiency. • Synergetic effect was observed in PEC degradation of MB with the applied bias of 15 V. [ABSTRACT FROM AUTHOR]

As an emerging technology to solve the bottleneck of plastic processing of light alloys, electromagnetic forming usually causes a complex mechanical response and microstructure evolution of materials. In this work, based on the electromagnetic ring expansion (EMRE) experiment, the relationship between microstructure evolution and mechanical properties of AA2219-T6 under EMRE with different discharge energies is established. In particular, to reveal the influence of strain and temperature parameters on the output response during the electromagnetic pulse process, a Q235 steel sleeve and an epoxy resin sleeve with different thermal conductivities are applied to constrain the deformation of the ring, respectively, thus the performance under electromagnetic treatment (EMT) are investigated. It is found that, under the threshold discharge energy of 4.23 kJ, the microhardness of the ring via EMT with the steel sleeve is similar to that of AA2219-T6, but increases by 20.9% compared with the ring via EMT with the epoxy sleeve and 17.1% compared with the ring via EMRE. The electromagnetic pulse has no significant effect on the evolution of precipitates in AA2219-T6-EMT (Steel), but the adiabatic temperature rise in AA2219-T6-EMT (Epoxy) caused redissolution of G.P.Ⅱ zones. With the gradual increase of discharge energy under EMRE, the microhardness of AA2219-T6 increases initially and followed by a decrease, while the fracture strain increases continuously. When discharge energy reaches 8.63 kJ, 2219 aluminum alloy has the optimal mechanical properties that, compared with AA2219-T6, the microhardness increased by 14.2% and the fracture strain increased by 18.0%. The dislocation density shows a trend of first increasing and then decreasing with the increase of discharge energy. Combined with the observed phase transformation, it is shown that dislocations generated by EMRE will promote G.P.Ⅱ zones to transform into θ ′′ phases, and affected by dislocation density, the transformation effect is most obvious at 8.63 kJ. In addition, the transformation of precipitates greatly increases the probability of hindering the motion of dislocations, which promotes the precipitates to be dispersed, and AA2219-T6 is further strengthened after EMRE. As discharge energy continues to increase, the dislocations begin to annihilate and G.P.Ⅱ zones are redissolved due to the adiabatic temperature rise. • G.P.Ⅱ zones are redissolved with a significant temperature rise in EMRE and EMT. • EMRE promotes the instant phase transformation affected by dislocation density. • The optimal performance under EMRE is obtained at a discharge energy of 8.63 kJ. [ABSTRACT FROM AUTHOR]

Monolayer MoTe 2 exhibits excellent electronic properties which can be widely utilized in opto- and nanoelectronic fields. Intrinsic defects are commonly formed in MoTe 2 growth, which would significantly influence the nature of the material. We systematically studied the electronic and magnetic properties of intrinsic defects including point defects and boundaries in monolayer MoTe 2 by means of first-principles calculations based on density functional theory (DFT). Results show that the defective structures could effectually induce magnetic moment with the exception of V Te , V Te2 , V MoTe3 , V MoTe6 as well as the 4|4a boundary. Briefly speaking, boundary defects are easier to induce magnetic generation than point defects. Additionally, the electronic structures of the defective structures were systematically analyzed to understand the origin of the observed magnetism. Moreover, different application foreground could be anticipated through the modulation of defect structures, for instance, 4|4b and 8|8b boundaries can form a metallic interface as well as the 6|6a structure can form spin gapless semiconductor(SGS), respectively. Our calculated results suggest that intrinsic structural defects in monolayer MoTe 2 could open a new platform to extend the application in spintronics and electronics. [ABSTRACT FROM AUTHOR]

Achieving high light absorption efficiency and low photogenerated carrier recombination rates is critical in the production of H 2 by photoelectrochemical water splitting. Antimony selenide (Sb 2 Se 3) has recently received much attention due to its favorable optoelectronic properties, low cost and unique nanorod structure. Herein, we constructed coral-like Sb 2 Se 3 /SnS 2 heterojunction by introducing SnS 2 with a nanosheet structure, which contributes to enhanced light absorption and provides more reaction sites. On this basis, synergistic optimization is carried out by the bilayer Sb 2 Se 3 structure and ferrihydrite (Fh) to effectively inhibit charge recombination at the interface and facilitate electron transport. Compared to monolayer Sb 2 Se 3 (1.54%), the IPCE value of bilayer Sb 2 Se 3 /SnS 2 /Fh can reach 20.56% (735 nm). The prepared bilayer Sb 2 Se 3 /SnS 2 /Fh has a maximum photocurrent density of approximately − 1.0 mA cm−2 at 0 V RHE , continuous testing for 1 h compared to monolayer Sb 2 Se 3 still maintains more than 4 times improvement. This work provides a basis for the development of high efficiency and low cost Sb 2 Se 3 -based optoelectronic devices. [Display omitted] • The bilayer Sb 2 Se 3 structure was constructed by sequential deposition. • A combination between 1D Sb 2 Se 3 nanorods and 2D SnS 2 nanosheets has been achieved. • Surface modification using ferrihydrite as an interface engineering material. • Optimized photoelectrode current density is 50 times higher than original sample. • The PEC mechanism of bilayer Sb 2 Se 3 /SnS 2 /Fh photoelectrode was proposed. [ABSTRACT FROM AUTHOR]

In this study, Eu 3+ and Tb 3+ co-doped Y 2 O 3 particles were prepared via the simple, cost-effective urea homogeneous precipitation method without additives. The chosen particles were added in the SiO 2 sols to get anti-reflection (AR) and wavelength conversion bi-functional films. Careful investigations were carried out to find the optimum preparation conditions and proper morphology. SEM images showed that the particle sizes reduced as metal ion/urea ratio decreased. Additionally, the extracted particles turned from sphere to lamellar type when the deionized water, which was used as solvent, reduced to a certain extent. The mechanisms of the morphology formation and diversification were proposed as well. The as prepared materials can convert UV region photos to visible photons between 460 nm and 640 nm, which just matched the spectral response of most solar cells. The spherical sample showed better luminescence performance than the one with lamellar morphology. In addition, the optical transmittance spectra indicated that the films adding spherical particles had better anti-reflective performance, and the best adding amount was 0.08 g. Finally, As a proof-of-concept application, the as prepared bi-functional films were used to test the standard monocrystalline silicon solar cell assembled with anti-reflection and wavelength conversion bi-functional films photoelectric conversion properties. As a result, the as prepared bi-functional films could effectively improve the photoelectric conversion efficiency by 0.23% compared to pure SiO 2 AR coating film and 0.55% compared to glass. [ABSTRACT FROM AUTHOR]

• Yb3+/Tm3+ co-doped β-In 2 S 3 photoanodes were fabricated on the FTO substrate in-situ as PEC water splitting photoanode. • The semiconductor sensitized up-conversion strategy was first applied to improve the PEC performance of β-In 2 S 3. • The donor states may be formed below the conduction band minimum (CBM) due to the intrinsic defects or doping. • Yb3+/Tm3+ co-doped β-In 2 S 3 leads to negative shift of Fermi level, which is favorable for carrier transfer and separation. N-type β-Indium sulfide (β-In 2 S 3) has emerged as one of the most promising semiconductor photoanode for use in photoelectrochemical water-splitting in recent years, its defective spinel structure facilitates the incorporation of foreign ions to adjust the photoelectrochemical (PEC) performance. Lanthanide ions with excellent optical properties and abundant energy level structure have attracted much attention. In this study, the semiconductor sensitized up-conversion strategy was first applied to improve the PEC performance of β-In 2 S 3 by inhibiting electron-hole pairs recombination. Yb3+/Tm3+ co-doped β-In 2 S 3 (YTS) were successfully prepared on FTO substrate in-situ as PEC water splitting photoanode by a simple hydrothermal method, the effects of Yb3+/Tm3+ co-doping on PEC properties, charge-transport properties and energy band structure are discussed. When Yb3+ ions in the total cations of precursor accounted for 3%, and Tm3+ ions accounted for 0.5%, the photocurrent density of Yb3+/Tm3+ co-doped β-In 2 S 3 (YTS-3) is 0.42 mA/cm2 (0.5 V vs. Ag/AgCl), which is about 1.68 times higher than pure β-In 2 S 3 (0.25 mA/cm2). No photocurrent response was detected under 980 nm single-wavelength LED, proving that host material sensitization is more effective than direct excitation. The improved PEC properties for Yb3+/Tm3+ co-doped β-In 2 S 3 might be attributed to the semiconductor sensitized up-conversion strategy, which realize a cycle of energy released by electron-hole pairs recombination. Moreover, the donor states formed after doping inhibits the recombination of electron-hole pairs by capturing electrons. The ways that the Yb3+/Tm3+ dopants modified the energy band structure and PEC properties of β-In 2 S 3 demonstrated in this study have guiding significance for the design of lanthanide ions doped semiconductor photoanode. [ABSTRACT FROM AUTHOR]