Journal of Materials Science最新文献

To address the lack of understanding regarding the synergistic reinforcement mechanism and interactive effects between Mo and WC particles within WC/FeCoNiCrMo high-entropy alloy (HEA) cladding layers, two types of laser cladding layers with a composition of 15 wt.% WC and 85 wt.% FeCoNiCrMo_x (x = 0.2, 0.5) were fabricated on 4Cr5MoSiV1 tool steel substrates. A comprehensive comparative study was conducted focusing on the macrostructure, micro texture, phase evolution, mechanical property, and corrosion-related performance of the layers. Furthermore, the effect of varying Mo levels on the co-regulation mechanism between Mo and WC during the microstructural evolution and performance optimization of the HEA cladding layers was systematically analyzed. The results reveal that both HEA layers exhibit dense metallurgical bonding with the substrate, free of flaws like pores or cracks. Increasing the Mo molar ratio from 0.2 to 0.5 leads to a significant phase transformation within the cladding layer, evolving from an FCC matrix with WC, W₂C, and Cr₇C₃ phases to the additional formation of σ and Co₄W₂C phases. This indicates that higher Mo content promotes σ phase precipitation, intensifies WC decomposition, and facilitates Co₄W₂C formation. Moreover, elevated Mo content enhances the nucleation of WC, leads to a smaller and more homogeneous grain structure within the 15%WC + 85%FeCoNiCrMo_0.5 layer, which achieves an average microhardness of 414.3 HV_0.2, an increase of 18.1% compared to the Mo_0.2 layer. Benefiting from the combined benefits of solid solution hardening, grain refinement, and secondary phase strengthening contributed by Mo and WC, the 15%WC + 85%FeCoNiCrMo_0.5 layer demonstrates the lowest wear loss and friction coefficient, with a wear rate as small as 6.85 × 10^–4 mm³/(N·mm), reflecting superior wear resistance. Electrochemical tests further confirmed that the 15%WC + 85%FeCoNiCrMo_0.5 coating exhibited the smallest corrosion current, higher corrosion potential and the largest impedance modulus (|Z|), indicating optimal corrosion resistance. This work elucidates the co-interaction mechanisms driven by the molar ratio differences of WC and Mo, providing theoretical guidance and method basis for the surface performance enhancement of HEA-based cladding systems.

An efficient Ag₂WO₄/BiFeO₃ heterojunction was successfully synthesized using a facile hydrothermal and in situ precipitation method. A comprehensive investigation was conducted into the morphological, structural, and optical properties of the Ag₂WO₄/BiFeO₃ heterojunction. The optimally synthesized Ag₂WO₄/BiFeO₃ heterojunction demonstrated an impressive removal efficiency toward Lanasol Red 5B (95.62%) within 100 min under simulated solar irradiation, which was 5.18-fold higher than pristine BiFeO₃. The engineered heterojunction effectively optimized the electron transfer pathway, significantly enhancing the separation efficiency of photogenerated electrons and holes. A notable selectivity of the Ag₂WO₄/BiFeO₃ heterostructure was observed in the photocatalytic degradation of organic dyes under simulated solar irradiation. The removal efficiencies followed the order: Lanasol Red 5B (95.62%) > Congo red (50.47%) > Methyl red (47.16%) > Safranin T (22.22%) > Rhodamine B (8.07%) > Methyl orange (3.04%). Furthermore, active species trapping experiments confirmed that holes and superoxide radicals were the predominant reactive species driving the photocatalytic process. This simple synthesis method opens up new possibilities for developing efficient BiFeO₃-based photocatalysts for environmental remediation purposes.

Our daily life is deeply intertwined with portable electronic devices, which become essential for communication and entertainment, such as laptops and mobile phones. To facilitate their operation, in this work, we focus on two-dimensional monolayer SnN₃ as an anode component for metal-ion battery applications using density functional theory (DFT). Computational simulations can provide insights into crucial parameters like adsorption energy, storage capacities, electronic conductivity, voltage profile, and energy barriers for ion diffusion. The SnN₃ monolayer reveals excellent dynamic, thermal, and mechanical stability, as a potential anode material for sodium-ion batteries (SIBs) with a high theoretical storage capacity of 333.47 mA hg⁻¹, a low average open-circuit voltage of 0.31 V, and a low diffusion barrier of 0.035 eV. Notably, at a maximum concentration of Na⁺, the in-plane lattice parameter changes by only 1.3%, indicating minimal structural deformation and suggesting excellent stability during charge/discharge cycles. These findings indicate that the SnN₃ monolayer is a potential Na host material for rechargeable SIBs and provides a valuable pathway to experimentalists investigating SnN₃-based anode materials designed for SIBs applications.

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This research seeks to improve high-temperature wear performance of magnesium-based alloys by examining the tribological behavior of in situ Aluminum Oxide (Al₂O₂) reinforced Magnesium–Lanthanum (Mg-La) composites. This research addresses the deficiencies of conventional magnesium alloys which exhibit low abrasion resistance when under thermal stress, although they possess an exemplary strength-to-weight ratio, to develop a lightweight, high strength material system for aviation uses. Al₂O₂-reinforced Mg-La composite is produced and compared to the unreinforced Mg-La alloys AZ91, ZE41, and Mg-6Gd-Zr-Ag. All alloys undergo wear testing at different loads and temperatures. Subsurface microstructural evaluation is conducted to clarify thermal stability, work hardening behavior, and grain recrystallization. Wear mechanism maps are created statistically to illustrate operational parameter impact on deformation and wear mechanism. AZ91 exhibited the highest wear resistance (0.25 mm³/Nm), followed by ZE41 (0.22 mm³/Nm), Mg-6Gd-Zr-Ag (0.17 mm³/Nm), and the Al₂O₂-reinforced Mg-La composite (0.12 mm³/Nm). Although wear resistance is lower than that of traditional alloys, the reinforced composite benefits from exceptional thermal stability, improved work hardening, and a higher resistance to grain recrystallization. The wear mechanism maps also illustrate how load and temperature significantly affect the deformation and wear processes, highlighting the advantages of the in situ Al₂O₂-reinforced Mg-La composite. In situ Al₂O₂-reinforced Mg-La composite effectively improves the high-temperature wear performance of Mg-based alloys, offering a promising approach for designing lightweight, thermally stable materials suitable for extreme service environments, particularly in the aerospace sector.

This study employs a machine learning (ML) approach to investigate the impact of composition and deformation parameters on the yield stress (YS) and ultimate tensile strength (UTS) for austenitic stainless steels at high temperatures. The input variables for the 10 ML models, used in the present investigation, are chemical composition (wt%), initial grain size (μm), strain rate (1/s), and temperature (°C). The dataset consists of 568 data points and 24 variables. The gradient boosting regressor (GBR) has emerged as the best model for predicting YS and UTS, with R-squared scores of 0.95 and 0.96, respectively. The SHAP plot revealed that the five variables delivering maximum impact for YS were temperature, strain rate, iron, initial grain size, and molybdenum, respectively. In contrast, temperature, strain rate, iron, nitrogen, and molybdenum were the first five features for UTS. The SHAP plot, which indicates the effect of each parameter on YS and UTS, has been constructed. According to the SHAP, strain rates increase is accompanied by an increase in Ni, N, and Mo percent for both YS and UTS. Conversely, higher temperatures, coarser grains, and a high value of Fe lead to a decrease in them. The experimental results also corroborated the GBR model and established its acceptability for predicting YS and UTS in austenitic stainless steels at high temperature.

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In this work, we report the microstructure and mechanical properties of Al-8.7Zn-2.1Mg-0.15Zr alloy curved profile with irregular cross-section based on self-bending extrusion, the extrusion was performed at temperatures of 410 °C, 440 °C, 470 °C, 500 °C, 530 °C, respectively. It is found the non-uniform flow of metal in the die could induce self-bending effect and, at the same time, led to microstructural heterogeneity on the profile cross-section. Moreover, low-temperature extrusion (< 440 °C) leads to surface cracking, while overburning at high temperatures (> 500 °C) degrades mechanical properties. As a result, a strength–ductility synergy is achieved for samples extruded at 470 °C, in this way, the tensile strength for long-edge and short-edge of the L cross section profile after aging were examined as 458 MPa and ≥ 469 MPa, and the elongations were tested as 12.3% and 11%, respectively. The grain boundary misorientation, recrystallization fraction, and substructure during deformation was found responsible for the differences in mechanical properties. Further, multiscale characterization on microstructures reveals a coordinated strengthening mechanism between intragranular η′ phases (< 6 nm) and Al₃Zr particles (~ 26 nm). The obtained results provide theoretical support for self-bending extrusion of high-strength aluminum alloy curved profiles.

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The microstructures of both the as-cast and solution-treated Mg–30Sc alloy were systematically characterized. The tensile properties of the as-cast and solution-treated Mg–30Sc alloy were evaluated at ambient temperature. For the solution-treated alloy, deformation twins were suppressed, and dislocation slip was the dominant plastic deformation mechanism during tensile test. Pyramidal < c + a > dislocations with a large scale Burgers vector (b = 2 < (overline{2})205 >) were detected in the alloy. The formation of these pyramidal < c + a > dislocations involves atomic shear displacement in both the < 01(overline{1})0 > and < 0001 > directions. Compared with other Mg–RE alloys under the same condition, the Mg–30Sc alloy achieves a combination of high strength and good ductility due to the activation of large-scale pyramidal < c + a > dislocations.

In the framework of integrated computational materials engineering (ICME), combined with high-throughput thermodynamic and kinetic calculations, the composition and intercritical annealing temperature were designed for a 1180 MPa grade low-carbon and low-alloy transformation-induced plasticity (TRIP) steel. The steel with a composition of Fe–0.26C–2.19Mn–0.91Si–0.76Al (wt%) had a good TRIP effect resulting from the retained austenite (RA) with higher stability. After intercritical annealing at 780 ℃ for 240 s, followed by over-aging at 370 ℃ for 300 s, the steel had an ultimate tensile strength (UTS) of 1261 MPa, a total elongation (TE) of 21.2%, and a product of strength and elongation (PSE) of 26.77 GPa%, exhibiting excellent mechanical properties. Moreover, due to the importance of bainite in balancing strength and plasticity, a kinetic model based on shear transformation was optimized by combining thermal expansion analysis with in situ analysis of the microstructural transformation in steels. The bainitic transformation in steels with annealed microstructures consisting of ferrite and austenite could be accurately predicted by the kinetic model, enabling the optimization of the over-aging temperature accordingly. This provided a theoretical basis for predicting the microstructure of TRIP steel and improving the integrated computational materials design method for advanced high-strength steels (AHSS).

Carbon dots (CDs) are nearly zero-dimensional fluorescent carbon nanomaterials, featuring excellent fluorescence (FL) properties, tunable optical characteristics, and good biocompatibility. These advantages make them uniquely advantageous in non-invasive tumor treatment. This review first introduces the principles of photodynamic therapy (PDT), photothermal therapy (PTT), sonodynamic therapy (SDT), and chemodynamic therapy (CDT). Secondly, it systematically elaborates on the application progress of PDT, PTT, SDT, and CDT in tumor treatment, among which the application of PDT in anti-tumor and antibacterial aspects is classified and elaborated. The unique feature of this review lies in its systematic classification of various treatment strategies, and it particularly emphasizes the synergistic effects of carbon dots in different therapies, highlighting the advantages of the multi-functional integrated platform in overcoming the limitations of single therapies.

Aluminum alloy has attracted wide attention due to its light weight and excellent specific strength. However, its low hardness and wear resistance limit its application in high-stress friction environments. In-situ reinforced particles exhibit clean interfaces, strong matrix bonding, and uniform dispersion, significantly enhancing the matrix’s hardness and wear resistance. In this study, (ZrB₂ + Al₂O₃) binary ceramic particles reinforced 6016Al composites were in-situ synthesized using an Al-Al(OH)₃-K₂ZrF₆-KBF₄ in-situ reaction system, which greatly improved the hardness, friction, and wear properties of the 6016Al alloy. The wear surface was characterized by SEM and XPS analysis, and the mechanism of reinforcing particles to improve the friction and wear properties of composites was studied. The influence and contribution of tribological parameters (time, load, speed) on the composite’s wear performance were systematically evaluated using gray relational analysis, Taguchi method, and analysis of variance (ANOVA). The results show that after adding the binary ceramic particles, the Vickers hardness of the composite is 63% higher than that of the 6016 Al alloy, reaching 99.48 HV. The friction coefficient of the composites is lower than that of 6016 Al alloy, and the wear rate is 38.5% lower than that of 6016 Al alloy. The results of the strengthening mechanism show that the composites are mainly abrasive wear and oxidation wear. The (ZrB₂ + Al₂O₃) binary ceramic particles reduce the adhesive wear in the initial friction stage, enhance the oxidation wear in the steady-state friction stage, and avoid the delamination wear in the terminal friction stage. The results of statistical analysis show that the order of the influence of friction parameters on the wear performance of composites is rotational friction velocity > time > load, and the contribution rates are 80.95%, 11.78%, and 3.04%, respectively.