Journal of Materials Science最新文献

Photocatalytic splitting of water to produce hydrogen can solve energy shortages. However, the high rate of electron–hole pair recombination triggered by light absorption poses a considerable challenge to the efficacy of single-component photocatalysts. The creation of van der Waals (vdW) heterojunctions has emerged as a highly effective strategy to mitigate the recombination of charge carriers. Therefore, first-principles computations were utilized to examine the stability, electronic characteristics, optical behavior, and photocatalytic mechanisms of the NiS₂/WSe₂ van der Waals (vdW) heterojunction. This heterojunction functions in the capacity of an indirect band gap semiconductor, exhibiting a band gap energy that has been determined to be 0.55 eV. It features a direct Z-scheme charge transfer mechanism, which has been shown to significantly enhance the separation of photocarriers (electrons and holes). Its valence band alignment fulfills the criteria for the redox of water over the full range of pH values. In comparison with monolayer materials, it exhibits a substantially augmented capacity for visible light absorption. Furthermore, it attains a noteworthy solar-to-hydrogen (STH) transformation efficiency of 14.93% during AM1.5G solar irradiation. Strain engineering further optimized its optical absorption and catalytic performance. The calculations of Gibbs free energy demonstrate that the NiS₂/WSe₂ heterojunction exhibits an efficient performance in oxygen and hydrogen evolution reactions (OER and HER), respectively. This study offers a material candidate with promising potential to be utilized in designing highly efficient photocatalytic systems.

In this paper, the formation mechanism of (1/6<11overline{2 }]) Shockley partial dislocation bow-outs in the γ phase of TiAl alloys was investigated during the warm shot peening (WSP). The movement of such partial dislocations was attributed to the formation of dislocation bow-outs, specifically triangular and trapezoidal ones. Each bow-out consisted of stacking faults (complete and incomplete) and a dislocation configuration (triangular or trapezoidal). Therefore, the formation energy of the bow-outs was obtained by calculating the energy summation of these stacking faults and dislocation configurations. By deducing and analyzing the formation energy, a critical bow-out angle was proposed to characterize the stability of the dislocation bowing. During the Shockley partial dislocation bowing process, the lattice changes in front of the stacking fault were revealed. The complex trajectories of Ti and Al atoms during these lattice changes were attributed to the coupling of lattice distortion and shear under the impact of shots.

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Adsorbents incorporating the natural polysaccharide chitin show significant potential for heavy metal enrichment. However, existing chitin hydrogels suffer from poor recyclability and low adsorption capacity, limiting their practical applications. To address these limitations, an interpenetrating network hydrogel (TOChNs-G) for the adsorption of heavy metal ions was prepared by cross-linking TEMPO-oxidized chitin nanofibers-composite gelatin with glutaraldehyde supramolecules. The morphology and graft modification of chitin were evaluated by TEM, XRD, and ATR-FTIR. The microstructure and mechanical strength of the hydrogel were characterized by SEM, rotational rheometer, and tensile testing. The adsorption capacities for the heavy metal ions Fe³⁺, Cr³⁺, Cu²⁺, and Mn²⁺ were investigated, yielding results of 613.8 ± 18 mg/g, 223.3 ± 11 mg/g, 85.9 ± 12 mg/g, and 87.4 ± 9 mg/g, respectively. The adsorbed metal ions in the hydrogel can be readily desorbed using a 0.3 M hydrochloric acid solution. The hydrogel demonstrated the ability to maintain its adsorption capacity over multiple adsorption/desorption cycles. It was concluded that the interpenetrating network hydrogels can effectively enrich heavy metal ions through electrostatic interaction between the positively charged metal ions and negatively charged carboxyl groups present in the structure. This environmentally friendly hydrogel material has the potential to serve as a high capacity, reusable, low-cost, and biomass-based sorbent for the removal of heavy metal ions from wastewater.

Graphical Abstract

A dilute Mg-0.88Zn-0.34Ce (ZE10, wt.%) alloy with high mechanical properties was successfully fabricated via low-temperature extrusion. The microstructural evolution and mechanical properties of ZE10 alloys obtained under different extrusion temperatures (250℃ and 300℃) and extrusion ratios (25 and 50) were systematically investigated. The alloy extruded at 250℃ exhibited a bimodal grain structure with an average grain size of approximately 1.62 μm. With increasing extrusion temperature and ratio, the microstructure transitioned from bimodal to fully dynamic recrystallized (DRXed), accompanied by an increase in average grain size. In the extruded ZE10 alloys, Zn and Ce elements co-segregated at grain boundaries (GBs), producing a pronounced solute drag effect that effectively refined the DRXed grains. This GB co-segregation became less pronounced at higher extrusion temperatures and ratios, thereby diminishing its grain-refining effect. Notably, the alloy extruded at 250℃ exhibited the optimum mechanical properties, with a tensile yield strength (TYS) of 315 MPa and an elongation (EL) of 8.5%. In contrast, alloys extruded at 300℃ demonstrated superior ductility, achieving elongations exceeding 30%. The enhanced mechanical properties of the ZE10 alloys are attributed to the combined effects of grain refinement, dynamic precipitation, and residual dislocations.

In recent years, piezoelectric–photocatalytic materials have attracted significant attention due to their potential to address environmental pollution issues in a straightforward, effective and sustainable manner. In this paper, Ag nanoparticles are successfully immobilized on the surface of ZnO, and a multifunctional PVDF-based water treatment membrane with piezoelectric–photocatalytic performance is constructed for the first time by combining the prepared ZnO@PDA-Ag composite nano-photocatalysts with the PVDF-g-IL piezoelectric matrix. The distinctive structure of ZnO@PDA-Ag enhances charge separation in the photocatalytic process, effectively promoting the photocatalytic activity of ZnO. The grafting IL onto PVDF chain segments induces a transformation of the polar crystalline phases within the PVDF. The synergistic effect of both results in significant improvements to the membrane’s porosity, increasing the permeate flux. The PVDF-g-IL/ZnO@PDA-Ag membrane demonstrates a high degree of efficiency in the removal of various dyes with an approximate removal efficiency of 100%. Furthermore, the PVDF-g-IL/ZnO@PDA-Ag membrane displays piezoelectric polarization, resulting in the formation of a built-in electric field when exposed to ultrasound, which enhances electron–hole separation and transfer efficiency. The membrane is capable of degrading approximately 98% of the dye within a 90-min degradation experiment. Finally, the PVDF-g-IL/ZnO@PDA-Ag membrane exhibits excellent mechanical stability even after multiple self-cleaning and recycling cycles.

This study provides a comprehensive thermodynamic description of the Fe–Sn–Ti ternary system using the CALPHAD method, integrating new differential thermal analysis results with experimental data and the literature to establish a consistent reaction scheme and phase diagram topology. The innovative aspects include confirmation of five ternary intermetallic compounds (τ₁–τ₁), identification of wide homogeneity ranges for τ₁, τ₂, and τ₅, and demonstration of significant ternary extensions of binary phases λ, ξ, and π. A key novelty lies in the discovery of three distinct monotectic reactions, including a unique continuous invariant four-phase monotectic reaction L ↔ L′′ + π + τ₁ at 1011.5 °C, accompanied by bell-shaped divergences in heat capacity rather than classical cusp-like singularities. This continuous equilibria framework offers a coherent interpretation of phase equilibria and thermodynamic behavior without violating the Gibbs phase rule, advancing understanding of liquid–liquid phase separation and ordering phenomena. The developed thermodynamic description enables reliable calculation of phase equilibria, showing good agreement with experimental data while highlighting areas of discrepancy that guide further refinement.

The effects of multistage rolling–aging treatment on the mechanical properties, electrical conductivity, and microstructure of Al-Cu-Sn alloy were investigated, and the underlying mechanisms were explained. The results show that the Al-1.5Cu-0.25Sn (3#) and Al-2.0Cu-0.25Sn (4#) alloys undergo this treatment and exhibit excellent comprehensive properties, with hardness values of 78 and 94 HV, electrical conductivity values of 62.0%IACS and 60.1%IACS, ultimate tensile strength values of 236 and 285 MPa, and elongation values of 13.5 and 10.5%. After multistage rolling–aging treatment, the precipitates of the alloy gradually change from plate-shaped to spherical-shaped. Additionally, the average size of the precipitates gradually decreases. The multistage thermomechanical treatment process maintains a high density of dislocations while forming numerous fine, dispersed, and uniformly distributed spherical precipitates, thereby enhancing the mechanical and electrical properties of the conductive aluminum alloy.

This study utilizes a rapid electrical resistance heating (ERH) technique to achieve complete microstructural reset and mechanical property recovery in plastically deformed SUS304 austenitic stainless steel, which addresses critical limitations in the sustainable metal manufacturing of high-performance components. Through multi-cycle interrupted tensile testing combined with controlled electric current parameters (350 A/2 s), the developed 2-s ERH processing method enables a complete recovery of original mechanical properties in 40% pre-strained samples, with yield strength reverting from approximate 600–260 MPa (virgin material: 260 ± 5 MPa). Microstructure analysis reveals that ERH facilitates the martensite-to-austenite reversion and dislocation annihilation during rapid recrystallization, which can be understood as the main reason of the mechanical property recovery. Specifically, the recrystallized grain fraction recovers from 1.8% in 40% pre-strain state to 96.5% (97.1% in base material), while the martensite phase decreases from 35.7 to 3.3% (5.5% in base material), and the Kernel average misorientation values revert from 1.28 to 0.33 (0.32 in base material) after ERH. These microstructure resets enable unprecedented mechanical property recovery to its original level with the entire processing time being only two seconds. The present study provides experimental evidence of full cyclic recovery in metastable stainless steels, facilitating closed-loop remanufacturing in multi-stage forming operations.

Stainless steel (SS) is widely employed in fields such as marine engineering due to its excellent corrosion resistance and mechanical properties. However, its limited strength and poor wear resistance hinder broader industrial application. Particle-reinforced stainless steel matrix composites (PR-SSMCs) are attracting significant research interest as they synergistically combine the hardness and wear resistance of reinforcing particles with the ductility and toughness of the SS matrix. Nevertheless, the optimal selection of reinforcing particles and fabrication methods for PR-SSMCs varies significantly with specific performance requirements and application conditions. Developing effective PR-SSMCs presents several challenges, including achieving uniform particle dispersion, ensuring strong interfacial bonding, controlling interfacial reactions, and managing microstructural evolution during heat treatment and hot deformation. A comprehensive understanding of the role of the reinforcing particles throughout the preparation process is crucial for improving the microstructure and properties of PR-SSMCs. However, current reviews primarily focus on particle-reinforced low-alloy steels or wear-resistant steels matrix composites, and a comprehensive review on PR-SSMCs is lacking. Therefore, this paper reviews recent advancements in PR-SSMCs, providing a detailed analysis of the advantages and disadvantages associated with various particle types (e.g., TiC, SiC, WC, VC, NbC, Al₂O₃, TiB₂, and hBN), fabrication techniques (e.g., stir casting, powder metallurgy, additive manufacturing, and master alloy method), heat treatment (e.g., annealing, tempering, aging, and solution treatment), and hot deformation strategies (e.g., hot rolling, hot forging, and hot compression). Additionally, future research prospects for PR-SSMCs are also briefly discussed.

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In this paper, the aluminum nanofoam compression and shear deformation behavior are investigated using molecular dynamics (MD) simulations with emphasis on the dislocation-based underlying mechanism and temperature dependence. Nanofoam structures with controlled relative density are generated by Voronoi tessellation and simulated quasi-statically using the embedded-atom method (EAM) potential. The simulations determine distinct deformation behaviors: Compression has three consecutive stages—elastic response, plastic plateau via ligament buckling, and densification—and shear deformation has initial linear elasticity followed by nonlinear hardening and localized shear banding. Size effects at the nanoscale significantly enhance the yield strength, with compressive strength higher than shear strength by approximately 30–40%. Power-law scaling of stiffness and yield stress with relative density is confirmed, as predicted by Gibson–Ashby. Dislocation analysis indicates that plasticity begins by Shockley partial dislocation nucleation at pore walls, growing dense dislocation networks under compression but developing toward a steady state under shear due to efficient dislocation annihilation at free surfaces. Elevated relative density enhances the material’s strength and hardness and reduces ductility, whereas elevated temperature lowers strength and stiffness significantly due to thermally activated dislocation motion. These observations represent atomistic visions of structure–property relationships in aluminum nanofoams and offer design hints for optimizing strength–ductility balance in weight-efficient structural applications.