Journal of Materials Science最新文献

The microstructure evolution and formation mechanisms of fivefold twin of copper nanoparticles during pressureless sintering are systematically investigated through molecular dynamics (MD) simulations. MD simulation results demonstrate that temperature and particle size uniformity exert pronounced influences on the sintering behavior of two copper nanoparticles. At low temperatures (below 800 K), dislocation slip predominantly governs atomic motion, limiting the formation of complex multiple twin structures. At high temperatures (above 800 K), however, particle rotation and high-energy surface decomposition critically contribute to the formation of asymmetric fivefold twin. Furthermore, size mismatch between particles inhibits twin formation and reduces the likelihood of fivefold twin formation. These findings provide fundamental insights into the fundamental mechanisms of fivefold twin evolution in metal nanoparticle sintering and underscore the critical role of sintering conditions in microstructure design and regulation of nanomaterials.

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Rare earth-containing magnesium alloys are critical materials in biomedical applications, yet their corrosion performance directly determines service safety. To overcome the time-consuming limitations of traditional experiments and the difficulty in quantifying complex corrosion mechanisms, this study established a machine learning prediction framework using literature-derived alloy compositions and environmental data. Six algorithms, including Random Forest Regressor, Extreme Gradient Boosting, and Support Vector Machine, were rigorously evaluated. Beyond standard grid search, an advanced optimization strategy integrating the Local Outlier Factor method for noise reduction and learning curve analysis was employed to effectively mitigate overfitting. The results indicate that the optimized Random Forest Regressor model achieved the highest accuracy for corrosion potential prediction (coefficient of determination (R^{2}) of 0.98 for training and 0.93 for testing), while the Extreme Gradient Boosting model excelled in predicting corrosion current density (coefficient of determination (R^{2}) of 0.97 for training and 0.94 for testing). Notably, validation through independent electrochemical experiments demonstrated the models’ excellent generalization ability, with prediction errors for corrosion potential and current density within 2% and 6.6%, respectively. Furthermore, Shapley Additive Explanations analysis identified Nd, Y, and Ca as key alloying elements, while Cl⁻ concentration and temperature were revealed as core environmental drivers. Finally, a Python-based graphical user interface was developed to provide an intuitive and rapid corrosion prediction tool for engineering applications.

Copper-based catalysts for Suzuki coupling reactions face limitations in efficiency and stability, while conventional palladium catalysts require high costs and harsh conditions. To address these challenges, we developed a bifunctional copper-loaded black phosphorus (Cu/BP) material. Initially, a series of Cu/BP catalysts (1–5 wt% Cu) were synthesized via wet chemical reduction. Subsequently, catalytic performance was evaluated using vector network analysis and a microwave catalysis system. Key results were obtained: Cu/BP-3 exhibited exceptional microwave absorption (minimum reflection loss: − 36.31 dB; effective bandwidth: 6.64 GHz). Under microwave heating (90 °C) with ultralow copper loading (0.25 mol%) in H₂O/CH₃OH (1:1 v/v), > 99.7% bromobenzene conversion was achieved within 2 h. This represents a 5.5-fold enhancement compared to conventional oil-bath heating. The catalyst maintained > 95% yields for bromobenzene substrates bearing strong electron-withdrawing/donating groups and ortho-substituents. Remarkably, > 95.4% activity retention was observed after 10 cycles, with copper leaching < 0.01 ppm. This work demonstrates that Cu/BP efficiently activates C–Br bonds through synergistic dielectric energy localization and interfacial charge transfer (P → Cu). It provides a new strategy for designing green, stable non-precious metal catalysts for microwave-driven reactions.

Mo⁶⁺-substituted Ni_0.5Zn_0.5Fe₂₋ₓMoₓO₄ (x = 0.00–0.10) ferrites were synthesized via a solid-state reaction at 1150 °C, aiming to tailor their microstructure and functional properties for high-frequency applications. X-ray diffraction confirmed the formation of a single-phase cubic spinel structure (Fd3m), with a systematic decrease in lattice parameter (8.361 → 8.348 Å) due to the incorporation of Mo⁶⁺ ions (0.59 Å) in place of Fe³⁺ (0.645 Å). TEM revealed densely packed grains with significantly reduced porosity (from 34.8 to 19.6%), while FTIR and EDS analyses confirmed preferential Mo⁶⁺ substitution at octahedral sites. This substitution suppressed Fe²⁺/Fe³⁺ electron hopping, resulting in a notable enhancement in bulk resistivity (up to 2756 kΩ cm), surpassing values reported for Co- and Ti-doped counterparts by 2.3 × and 275 × , respectively. The optimal composition (x = 0.10) exhibited low dielectric loss (tanδ = 2.03 at 1 kHz) and retained soft magnetic behavior (Hc = 21 Oe, Ms = 71.6 emu/g). This work provides the first demonstration of Mo⁶⁺ dual role as a charge compensator (suppressing Fe²⁺ formation) and grain boundary modifier (reducing interfacial losses), offering a breakthrough in designing low-loss ferrites. These findings demonstrate the potential of Mo⁶⁺ doping as an effective strategy to develop high-performance ferrites for advanced components like miniaturized inductive elements and electromagnetic interference (EMI) suppression applications where high resistivity and soft magnetism are critical.

Optimizing the mechanical performance of near-β titanium alloys requires a clear understanding of how multi-scale α phase morphologies influence tensile deformation behavior. This study aims to elucidate the relationship between the α phase fractions tailored by different heat treatment conditions and the resulting tensile response of a Ti-5Al-5Mo-5V-1Cr-1Fe alloy. Microstructural characterization and tensile testing were conducted on specimens with varying proportions of primary (α_p) and secondary (α_s) α phases. The results show that microstructures with a higher volume fraction of α_p and a lower volume fraction of α_s can achieve a favorable balance between ultimate tensile strength and fracture strain (1190.3 MPa, 7.85%). This is attributed to the reduced amount of α_s, which allows dislocations to migrate toward the vicinity of the α_p, thereby enabling the α_p to accommodate plastic deformation through coordinated dislocation slip. In contrast, alloys with increased α_s content exhibit significantly higher strength (1479.7 MPa) but reduced ductility (3.17%), as the α_s phase strongly pins dislocations and constrains plastic deformation. In microstructures with a high content of α_p and a relatively low content of α_s, the pinning effect of α_s is weakened, allowing dislocations to glide more readily and rendering deformation predominantly governed by dislocation slip. The equiaxed α_p phase facilitates the activation of multiple slip systems, whereas the rod-like α_p phase tends to promote single-slip deformation. Overall, the hierarchical distribution of multi-scale α phases enables uniform strain accommodation, leading to an improved strength and ductility synergy in the Ti-5Al-5Mo-5V-1Cr-1Fe alloy system.

Dye-sensitized solar cells (DSSCs) have gained significant attention as a promising class of third-generation photovoltaic devices owing to their low cost, ease of fabrication, and tunable optical properties. However, their practical use is still limited by poor electron transport, charge recombination, and low power conversion efficiency. This study tackles the persistent challenge of low efficiency in dye-sensitized solar cells (DSSCs) by introducing a novel polythiophene/titanium dioxide (PTh/TiO₂) hybrid nanocomposite photoanode. The photoanode was fabricated using the tape-casting technique, which enabled the deposition of a uniform TiO₂ film. This TiO₂ photoanode was later sensitized with cis-Bis(isothiocyanato)bis(2,2′-bipyridyl-4,4′-dicarboxylato)ruthenium(II) (N3dye), allowing efficient light absorption and electron transportation. The device performance was further improved by employing a graphene-based counter electrode. The fabricated photoanodes were systematically characterized using SEM, ellipsometry, UV–Vis spectroscopy, and Hall measurements to investigate the link between material properties and photovoltaic performance. By integrating conductive polymer networks with TiO₂ nanoparticles, the hybrid photoanode was developed to boost electron transport and light harvesting. The systematic investigation of PTh/TiO₂ loadings revealed that the photoanode containing 9 wt% PTh/TiO₂ achieved the highest DSSC efficiency of 0.86%, with an open-circuit voltage (Voc) of 0.56 V, short-circuit current density (Jsc) of 2.53 mA/cm², and a fill factor of 58.96%. This composition significantly outperformed devices with lower (5%, 7%) and higher (11%) PTh contents, underscoring the pivotal role of optimized nanocomposite architecture in enhancing charge transport and light harvesting. Furthermore, the results highlighted that increasing nanocomposite concentration directly influenced morphology, film thickness, light absorption capacity, and carrier mobility, ultimately shaping device performance.

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In this study, lignin-based carbon quantum dots (CQDs) were prepared by a one-step hydrothermal method using alkaline lignin as the carbon source and then further combined with ZnIn₂S₄ photocatalyst to construct a series of CQDs-X/ZnIn₂S₄ composite photocatalyst. The experimental results indicated that when the loading amount of CQDs was 20 mL, the composite material exhibited the best photocatalytic hydrogen production performance. Structural characterization revealed that CQDs with a size of 4–6 nm were successfully modified on the surface of flower-like ZnIn₂S₄ photocatalyst microspheres assembled by nanosheets, forming a tight heterostructure. Optical and electrochemical tests confirmed that the introduction of CQDs effectively broadened the light absorption range, adjusted the band structure and significantly promoted the separation and transfer of photogenerated carriers, while reducing the charge recombination rate. In addition, compared with pure ZnIn₂S₄ (48.18 m²·g⁻¹), CQDs-20/ZnIn₂S₄ has a relatively larger specific surface of 79.33 m²·g⁻¹, providing more active sites. This study demonstrated that the composite strategy based on lignin CQDs could significantly enhance the photocatalytic performance of ZnIn₂S₄ photocatalyst, providing an effective approach for the high-value utilization of lignin and solar hydrogen production.

The effect of grain size on the mechanical behavior of nanopolycrystalline magnesium (Mg) was investigated using molecular dynamics (MD) simulation. In the case of samples with larger grain sizes, dislocation-controlled mechanisms govern compressive deformation, whereas grain-boundary-mediated mechanisms, involving coordinated grain motion, dominate the deformation process in samples with smaller grain sizes. Complex dislocation behaviors, such as “jog pair” cross-slip, have been reported. Planar defects, including stacking faults (SFs) and twin boundaries (TBs), were analyzed at the atomistic scale. Furthermore, the grain size distributions of the samples were evaluated and compared during the compression process. Grain refinement and specific grain growth are also observed. The findings of this study can aid in understanding the impact of the grain size on the compressive deformation mechanism of nanopolycrystalline Mg.

The construction of high-performance manganese-based cathode materials with good charge and discharge stability is the key to the development of aqueous zinc-ion batteries. In this study, a Mn₂O₃@PPy composite cathode was successfully synthesized by integrating porous Mn₂O₃ spheres with a conductive polypyrrole (PPy) coating. The electrochemical performance and Zn²⁺ storage mechanism of the composite were systematically investigated. The PPy layer, as a conductive and protective layer, can enhance electrical conductivity, reduce interfacial charge transfer resistance, and prevent immediate contact between Mn₂O₃ and the electrolyte. This effectually suppresses the Mn³⁺ disproportionation reaction, thereby enhancing structural stability and extending the cycling lifespan of the electrode. It can be concluded that the Mn₂O₃@PPy cathode achieves an initial discharge capacity as high as 456.5 mAh g⁻¹ at 0.1 A g⁻¹. Notably, even after 1000 cycles at 1.0 A g⁻¹, it retains a capacity of 101.5 mAh g⁻¹, demonstrating excellent cycling stability and durability.

Vanadium pentoxide (V₂O₅) thin films have emerged as versatile functional materials with exceptional potential across multiple technological domains, including electrochromic devices, energy storage systems, and advanced sensors. This comprehensive review examines the recent advances in V₂O₅ film technology, with particular emphasis on sophisticated doping strategies and interface engineering approaches that have revolutionized their performance characteristics. The unique layered crystal structure of V₂O₅, featuring van der Waals gaps between V₂O₅ layers, provides exceptional opportunities for intercalation-based applications while presenting challenges in achieving optimal film properties. Recent developments in atomic-level doping control and interface optimization have led to significant breakthroughs in film stability, electronic conductivity, and electrochemical performance. This review critically analyzes synthesis methodologies ranging from traditional physical vapor deposition to emerging atomic layer deposition techniques, with a detailed examination of how processing parameters influence final film properties. We provide comprehensive coverage of metal cation doping (Li⁺, Ti⁴⁺, Mo⁶⁺, W⁶⁺), anion substitution strategies, and innovative co-doping approaches that have enhanced both fundamental properties and device performance. Interface engineering strategies, including substrate selection, buffer layer implementation, and surface functionalization, are examined for their roles in improving film adhesion, electronic properties, and long-term stability. The review identifies critical knowledge gaps in understanding doping mechanisms at the atomic level and provides a roadmap for future research directions, including machine learning-guided optimization and scalable manufacturing approaches for commercial applications.