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For precipitation-strengthened Al alloys, the interfacial segregation behavior of alloying elements plays an important role in controlling the effectiveness of precipitation strengthening. In this work, the adhesion work (Wad) and interfacial energy (γ) of the η(0001)/Al(111) interface were studied to gain an insight into the interface properties between the precipitate η and the Al matrix. Additionally, we examined the impact of the segregation behavior of alloyed elements on the bonding strength of the interface. The computed values for Wad and interfacial energies indicated that the T6S3 terminated configuration represents the interfacial structure with the highest stability across all models analyzed. Focusing on the T6S3 interface, the assessed segregated energies (Eseg) disclose that the segregation ability of elements from strong to weak exhibits the order of Ti > Sc > Zr > Y > Ta > Nb > Lu > Hf > Mo > V > W, while Cr and Mn elements are not easy to segregate at the interface. Sc, Ti, V, Cr, Mn, Zr, Nb, Mo, Hf, and Ta preferentially occupy Al atoms, whereas Y and Lu predominantly inhabit Mg atoms. Relative to the clean interface, the electron cloud enrichment at the interface after alloying element X (Zr, Sc, Ti, W, Hf, Mn, Y, Lu and V) doping is weakened, and the ion interaction among interface atoms is enhanced. After doping alloying element X (Nb, Mo, Ta, and Cr), the degree of electron cloud enrichment at the interface is obviously enhanced, and the covalent interaction among interface atoms is enhanced. This suggests that the introduction of alloyed elements through doping can augment the bond strength at the interface between the precipitated phase and matrix, thereby reinforcing the strength and toughness of 7xxx series alloys. [ABSTRACT FROM AUTHOR]

This paper constructs a single O and S functionalized Zr2N model for surface levelling and at the same time a series of bifunctional models with different functional group ratios and distributions. The influence of these functional groups on the electrochemical and lithium storage properties of Zr2N materials has been systematically investigated in terms of lithium atom adsorption, migration and lithium storage capacity. Among them, the theoretical lithium storage capacities of Zr2NO2 and Zr2NS2 with a low migration barrier are more than 755.02 and 678.30 mA h g−1, respectively. The results show that the O and S-functionalized Zr2N materials are all metallic and capable of adsorbing a certain number of lithium atoms. By controlling the ratio and distribution of the O and S functional groups, the adsorption position and adsorption energy of the lithium atoms can be influenced to a certain extent. Especially, the aim of improving the lithium storage performance of the material can be achieved in this way. [ABSTRACT FROM AUTHOR]

Gradient induced unusual strain hardening achieves the equilibrium of the strength and plasticity of alloys, and is an important strategy for the optimization of the mechanical properties of metals and alloys. The segregation of solute elements can greatly improve the grain boundary stability, inhibit grain coarsening and promote the mechanical strength of the alloy. In our efforts, the segregation structure of the solute element Co was designed and added to the gradient nano Ni–Co alloy, and the two strengthening strategies were applied simultaneously in one structure. The mechanical strength of the alloy achieved a second increase based on the unique combination of gradient induced strain hardening and high plasticity, especially the yield strength of alloy increase amplitude reach to 42%. This provides a positive direction for the alloy strengthening strategy. In the process of secondary strengthening, the micro-mechanism is divided into two stages: in the first stage, the gradient strain provides the alloy with geometrically necessary dislocations and a multi-axial stress state, and the existence of large numbers of geometrically necessary dislocations creates good conditions for the second stage strengthening. In the second stage, the solute segregation induced stable grain boundaries produce a strong pinning effect on the geometrically necessary dislocation, which realizes the coupling of grain boundary strengthening and dislocation strengthening. This provides a new strengthening strategy and positive theoretical guidance for the experimental preparation of advanced alloys with excellent properties. [ABSTRACT FROM AUTHOR]

The electronic structure and photocatalytic performance of GaSe/MoSSe and Ga2SSe/MoS2 heterojunctions are systematically investigated by means of first-principles calculations. The outcomes demonstrate that the IV and II stacking patterns feature the lowest binding energies and the shortest interlayer spacing, wherein the A stacking configurations show typical type-II band alignment characteristics which are conducive to fulfill effective separation of electron–hole pairs in space. The electrostatic potential and the CDD indicate the generation of built-in electric fields from MoSSe to GaSe layers and from Ga2SSe to MoS2 layers, respectively, in the interfacial domain, providing a theoretical basis for the examination of the photocatalytic mechanism. The two heterojunctions are more preferable for the photocatalytic decomposition of water under acidic and neutral atmospheres at dissimilar pH levels. For the GaSe/MoSSe heterojunction, the band gap follows a monotonic decreasing tendency when the tensile strain increases from 0% to 6%, while in the case of compressive strain, the band gap increases and then decreases, and the heterojunction cannot undertake the water oxidation process when the tensile strain surpasses 2%. Meanwhile, when a compressive strain of 0% to 3% is imposed, the heterojunction redox potential always traverses the redox potential of water, wherein the photocatalytic performance is sustained. For the Ga2SSe/MoS2 system, the band gap value decreases monotonically with the exertion of both tensile and compressive strains. Moreover, it is applicable to photocatalytic water decomposition in the strain range of −6% to 6%. The absorption coefficients reveal that the two heterojunction system has a higher peak in the visible range than the corresponding monolayer, indicating a higher light absorption intensity. Furthermore, the electron mobility of heterojunctions along both directions is significantly higher than that of MoS2 and WSe2 monolayers, and GaSe/HfS2 and K2Se/Cs2S heterojunctions. These findings propose that both GaSe/MoSSe and Ga2SSe/MoS2 heterojunctions can be utilized as potentially better catalysts for the photocatalytic decomposition of water. [ABSTRACT FROM AUTHOR]

Herein, (VO)2P2O7 nanosheets function as a highly-active electrocatalyst for the hydrogen evolution reaction with an ultralow overpotential of 30 mV at 10 mA cm−2 in basic media, being close to Pt/C. Furthermore, as a bifunctional electrocatalyst, (VO)2P2O7 not only exhibits high activity but also good stability for overall water splitting. [ABSTRACT FROM AUTHOR]

Herein, the definite structure-dependent evolution process upon lithiation/delithiation and clear atomic images of pure 1T-phase SnS2 were obtained for the first time, illustrating the different insertion–conversion–desertion processes of discharge/charge plateaus. Also, 1T SnS2 exhibited advantages over commercial SnS2 (mixed with 1T and 1H phases) in cell resistance and lithium-storage performance. [ABSTRACT FROM AUTHOR]

For precipitation-strengthened Al alloys, the interfacial segregation behavior of alloying elements plays an important role in controlling the effectiveness of precipitation strengthening. In this work, the adhesion work ( W ad ) and interfacial energy ( γ ) of the η(0001)/Al(111) interface were studied to gain an insight into the interface properties between the precipitate η and the Al matrix. Additionally, we examined the impact of the segregation behavior of alloyed elements on the bonding strength of the interface. The computed values for W ad and interfacial energies indicated that the T6S3 terminated configuration represents the interfacial structure with the highest stability across all models analyzed. Focusing on the T6S3 interface, the assessed segregated energies ( E seg ) disclose that the segregation ability of elements from strong to weak exhibits the order of Ti > Sc > Zr > Y > Ta > Nb > Lu > Hf > Mo > V > W, while Cr and Mn elements are not easy to segregate at the interface. Sc, Ti, V, Cr, Mn, Zr, Nb, Mo, Hf, and Ta preferentially occupy Al atoms, whereas Y and Lu predominantly inhabit Mg atoms. Relative to the clean interface, the electron cloud enrichment at the interface after alloying element X (Zr, Sc, Ti, W, Hf, Mn, Y, Lu and V) doping is weakened, and the ion interaction among interface atoms is enhanced. After doping alloying element X (Nb, Mo, Ta, and Cr), the degree of electron cloud enrichment at the interface is obviously enhanced, and the covalent interaction among interface atoms is enhanced. This suggests that the introduction of alloyed elements through doping can augment the bond strength at the interface between the precipitated phase and matrix, thereby reinforcing the strength and toughness of 7xxx series alloys.

Herein, the definite structure-dependent evolution process upon lithiation/delithiation and clear atomic images of pure 1T-phase SnS2 were obtained for the first time, illustrating the different insertion-conversion-desertion processes of discharge/charge plateaus. Also, 1T SnS2 exhibited advantages over commercial SnS2 (mixed with 1T and 1H phases) in cell resistance and lithium-storage performance.