Journal of Materials Science最新文献

This study aims to enhance the wear and corrosion resistance of 27SiMn steel hydraulic support columns used in coal mines by developing a protective multilayer Fe-based coating via high-speed laser cladding. The microstructure, phase composition, hardness distribution, wear performance, and corrosion performance of the eight-layer stacked Fe-based coating prepared on the 27SiMn steel substrate were systematically characterized. The results show that the equiaxed grain size of eight-layer Fe-based coating is refined to 1.24 µm due to the reduction in substrate dilution and the additional nucleation points generated during dynamic recrystallization in the multilayer stacking process. The eight-layer Fe-based coating with a high content BCC phase presents more uniform hardness distribution than one-layer Fe-based coating, and its hardness variation ranges from 444 to 569 HV_0.3. The wear rate of eight-layer coating is reduced by 83.90% compared to the substrate, and the related wear mechanism is dominated by abrasive wear, accompanied by adhesive wear and oxidative wear. The corrosion mechanism of coating is mainly attributed to the increase in defect density of the Cr₂O₃ and Fe₂O₃ films during the immersion process, which enhances the pitting corrosion sensitivity. However, the coating’s electrochemical performance after 45 days of immersion remains superior to that of the substrate after 15 days of immersion. Moreover, after 300 days of immersion in the coal mine environment, the corrosion rate of Fe-based coating is only 8% of substrate, confirming that the coating can significantly extend the service life of hydraulic support columns.

The rational design of advanced anode materials is central to overcoming the limitations of conventional lithium-, sodium-, and magnesium-ion batteries. Here, we propose and systematically investigate a novel VS₂/nitrogen-doped graphene (VS₂/NGr) nanocomposite using density functional theory (DFT). The heterostructure exhibits a negative formation energy (− 0.025 eV), confirming thermodynamic stability, while nitrogen doping enhances interfacial coupling and charge redistribution. Electronic analysis reveals intrinsic metallic conductivity, and mechanical simulations demonstrate outstanding 2D stiffness (502.9 N/m) and stretchability, ensuring robustness during cycling. Electrochemical evaluations demonstrate strong ion adsorption and ultralow diffusion barriers of 0.16 eV (Li⁺, Na⁺) and 0.32 eV (Mg²⁺), enabling rapid and selective ion transport. The system achieves average open-circuit voltages of 0.70 V (Li), 0.55 V (Na), and 0.15 V (Mg), with corresponding theoretical specific capacities of 1153, 961, and 1922 mA·h·g⁻¹, respectively. These results demonstrate superior performance compared to pristine VS₂, graphene, and many reported 2D heterostructures. Collectively, these findings position VS₂/NGr as a robust, high-capacity, and rate-capable anode, and highlight heteroatom doping and van der Waals engineering as effective strategies for designing next-generation energy storage systems.

The effect of magnetic field aging on the microstructure of the polycrystalline Fe-Mn-Al-Ni-Ta-B alloy has been investigated with its impact on superelasticity. Specifically, its microstructure evolution including the appearance of beta-Mn phase, the significant increase in dislocation density, and the suppressed growth of nanosized ordered precipitates in an alloyed version of the Fe-Mn-Al-Ni alloy aged at 1 T, was elucidated by a comparative study with that alloy aged at 0 T. For the parallel-aligned beta-Mn phase, the premature at low aging temperature exerted fluctuations in components, induced a high density of dislocations in dual phases, leading to an enlarged martensitic transformation loop of thermal hysteresis. For the nanosized precipitates, a dramatic decrease in average size and their growth suppressed the increase in anti-phase boundary revealed their strong pinning effect, resulting in a reduction in the reversible motion of the austenite/martensite (A/M) interface. Evidence of the deteriorous reversible motion of A/M interface induced by magnetic field aging demonstrated the origin deduce in the superelasticity for that alloy. Regarding the detrimental effect in martensitic transformation and superelasticity, our findings detail the useful insights into the regulation and tailoring the service performance of FeMnAlNi-based superelastic alloys in the low magnetic field (e.g., geomagnetic field) regime.

Among various energy storage devices, supercapacitors have garnered significant attention due to their unique advantages, including high power density, rapid charge–discharge capability, and long cycle life. However, conventional electrodes typically rely on non-conductive binders, which complicate the fabrication process, increase production costs, and limit pore structure tunability, ultimately reducing energy density. In this study, we developed a self-supporting paper-based electrode with tunable micro-/mesoporous structures by integrating the highly crystalline lamellar microfibril structure of lyocell fibers and the high aspect ratio of softwood pulp fibers, through a combination of wet papermaking, thermal carbonization, and phosphoric acid activation. The fibrillation behavior of lyocell fibers enhanced inter-fiber hydrogen bonding and phosphate ester linkage formation, facilitating ion transport within the electrode. By adjusting the beating revolutions and fiber composition, the micropore volume ratio (V < sub > mi < /sub > /V < sub > tot < /sub >) was effectively tuned between 18.2% and 67.7%. Softwood pulp fibers served as a reinforcing scaffold, significantly improving the mechanical strength and enabling the self-supporting property of the material. The resulting electrode exhibited a high specific surface area of 1876 m²/g and delivered a specific capacitance of 225 F/g at 1 A/g in a three-electrode system, with a remarkable capacitance retention of 99.8% after 10,000 cycles. This work offers a promising strategy for the cost-effective and scalable fabrication of high-performance paper-based electrodes, demonstrating significant potential for application in energy storage systems.

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The aim of this study is to evaluate the chemical durability and surface stability of ion-exchanged glasses under accelerated weathering conditions. Two glass compositions, soda-lime silicate (SL) and soda-magnesia silicate (SM), were subjected to ion-exchange treatments at temperatures ranging from 425 °C to 475 °C for durations of 4 and 24 h. Subsequently, the treated glasses were exposed to artificial weathering in a humidity chamber at 120 °C and ~ 100% relative humidity for 48 h. The compressive stress induced by ion exchange was measured using a surface stress meter, while contact angle measurements were performed to assess surface wettability, revealing a hydrophobic character. The penetration depth and variation of potassium after weathering were examined using SEM–EDS, supported by detailed chemical analysis via D-SIMS. Optical transmittance was evaluated through UV–Vis–NIR spectroscopy, and after weathering, optical imaging highlighted surface alterations. Depth profiling from EDS and D-SIMS confirmed that chemically strengthened glasses exhibit enhanced resistance to artificial weathering, making them suitable for marine applications such as yacht windows, where durability and clarity under harsh environments are critical.

Strontium aluminate (SrAl₁₂O₁₉) has emerged as a promising host lattice for luminescent materials due to its excellent structural stability, thermal resistance, and wide optical bandgap. In this study, nano-sized SrAl₁₂O₁₉ phosphors were synthesized via a solid-state route and systematically doped with Eu³⁺ (5 mol%), Mn⁴⁺ (0.5–5 mol%), and their co-doped (Eu–Mn) combinations to explore structural, morphological, and optical properties. X-ray diffraction confirmed the formation of a phase hexagonal magnetoplumbite structure, while FESEM revealed morphology variations from plate-like grains (~ 1 µm) to rod-like particles (~ 400–600 nm) and nanospherical features (~ 20 nm). Optical absorption extended broadly from 200–380 nm. Eu³⁺-doped samples displayed characteristic emission bands at 590, 600, and 612 nm, producing reddish-orange luminescence, while Mn⁴⁺-doped samples exhibited deep-red emissions at 641, 656, and 667 nm, with maximum intensity at 1 mol% Mn. In Eu–Mn co-doped systems, enhanced Eu³⁺ emission and reduced Mn⁴⁺ intensity confirmed partial energy transfer, yielding tunable reddish-pink to mixed chromaticity. Colour coordinate analysis under 365 nm excitation highlighted optimal luminescence in SrAl₁₂O₁₉:1 mol% Mn–5 mol% Eu, combining superior intensity and emission tunability. These findings demonstrate the potential of Eu/Mn co-doped SrAl₁₂O₁₉ phosphors for next-generation solid-state lighting and full-colour display applications.

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Calcium magnesium phosphosilicate glasses doped with TiO₂ with nominal composition 30 CaO–(20–Y) MgO–YTiO₂–5P₂O₅–45SiO₂ (mole%, Y = 0, 1, 2, 4, and 6 mol %) were prepared via the melt quenching. Addition of TiO₂ promotes the formation of Ti–O–Ti and/or Si–O–Ti linkages that increases the glass network compactness, and leads to clear improvements in mechanical properties (higher modulus and hardness) and dielectric performance (higher ε′ with low loss and a new localized relaxation). The elastic modulus rises with Ti due to stronger bonding and reduced free volume. The real permittivity (ε′) increases with Ti content and temperature, while dielectric loss (ε″) decreases at low frequency and a mid-frequency relaxation (10–100 kHz) grows stronger with Ti. Conductivity falls with Ti addition as long-range ion motion is suppressed and charge carriers become more localized. The Ti-doped phosphosilicate glasses are lead-free and show stable, tunable dielectric behavior suitable for capacitors, insulating layers, and energy-storage devices.

The manufacturing process and the mechanical properties of particle reinforced metal matrix composites are strongly dependent on their microstructural characteristics. In this research, numerical simulations in 2D mesoscale of tungsten alloys reinforced by Zr(Y)O₂ particles (W-Zr(Y)O₂) were conducted to investigate their uniaxial compression deformation behaviours. With the increase in Zr(Y)O₂ mass fraction, the yield strength and compressive strength of the alloy increase gradually. The stress distribution coefficient q is always greater than 1 and increases from 1.66–1.72 to 1.76–1.81 with the increase in Zr(Y)O₂ content. Higher particle content accelerates the initiation of matrix damage and causes a shift in crack initiation locations. The segregation degree parameter τ = 0.664 reduces the material’s fracture strain, while τ ≤ 0.395 has a minimal impact on fracture strain. Particle fracture is the main cause of the decrease in fracture toughness of composites with low particle volume fractions. At the same Zr(Y)O₂ mass fraction, the smaller the particle size, the higher the alloy’s maximum compressive strength, and the average stress of the matrix and particles as well as the q-value also increase accordingly. When the overall material strain is 0.11 and the particle centre distance is 1.8 μm, a strain extreme point appears in the matrix between particles, and this extreme point is approximately 1.675 times the particle radius away from the particle centre. The current researches may be necessary for the mechanical design of structural materials in computational materials science.

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This study characterises the effects of crystal orientation on the evolution of austenite decomposition to ferrite/martensite in AISI-304 stainless steel, induced by exposure to gallium ions with a focused ion beam. Samples were exposed to the beam multiple times and imaged by electron backscatter diffraction before and after successive exposures, with the data aggregated by orientation clustering to derive insights into the effects of orientation on phase change processes. Propensity to decomposition and produced surface morphologies were observed to have a strong dependence on orientation. Three distinct orientation-based transformation behaviours were observed: grains with beam orientations close to the (langle 1 0 0rangle gamma) and (langle 1 1 0rangle gamma) axes remained untransformed or become amorphised; grains with beam orientations close to the (langle 1 1 1rangle gamma) axis were partially transformed to non-contiguous products at various absolute orientations with beam orientations close to the (langle 1 1 0rangle alpha) axis; and grains with beam orientations not close to any of the three principal axes were fully transformed to a single contiguous product with beam orientations close to the (langle 1 0 0rangle alpha) axis. Grains were not produced close to the (langle 1 1 1rangle alpha) axis in any case.

Zn–Ca composite phosphate coatings were successfully prepared on 30CrMo low-alloy steel via current-assisted phosphating in a phosphate solution containing non-polluting accelerators. The microstructure and chemical composition of the coatings prepared under different current densities (3, 6, 9, 12 mA/cm²) were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FT-IR). The composite coatings primarily consisted of CaZn₂(PO₄)₂·2H₂O, Zn₂Fe(PO₄)₂·4(H₂O), Zn₃(PO₄)₂·H₂O, and metallic zinc. With increasing current density, both the thickness of the coatings and the metallic zinc content increased significantly. However, the excessively high current density (12 mA/cm²) reduced the uniformity and increased the porosity of the coatings. Electrochemical tests and immersion experiments in NaCl solution indicated that the composite coatings enhanced the corrosion resistance of the steel through the synergistic effect of cathodic protection by metallic Zn and the physical barrier provided by the phosphate coatings in the early stage of corrosion. During the mid-to-late stages of corrosion, a dense layer formed by Zn₅(OH)₈Cl·H₂O and phosphate compounds offered physical protection to the substrate. Notably, the coating formed under a current density of 6 mA/cm² showed the highest impedance and the lowest hydrogen evolution, indicating superior corrosion resistance.

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