Advanced Engineering Materials最新文献

Ultra-high molecular weight polyethylene (UHMWPE) possesses excellent wear resistance and low friction but suffers from poor metal adhesion due to its low surface energy and chemical inertness. Herein, a graphene-mediated electroplating strategy is developed to enable dense and adherent Ni coatings on UHMWPE. The graphene interlayer enhances interfacial conductivity, promotes uniform Ni nucleation, and suppresses oxidation. Systematic optimization of NaCl concentration, current density, and plating time identifies current density as the dominant factor. Under optimal conditions, a compact 224 μm Ni layer yields a 37.9% reduction in friction coefficient. This work demonstrates an effective graphene-assisted metallization route for inert polymers, offering a pathway toward robust, low-friction engineering interfaces.

This work presents the integrated application of topology optimization and additive manufacturing (AM) to develop lightweight structural components for space robotic systems, focusing on the deployment arm and rocker support of the Lunar Volatiles Mobile Instrumentation—Extended lunar rover. These components are subject to stringent performance requirements under reduced gravity, launch-induced vibrations, and terrain-induced loading. A level set-based (LSB) topology optimization approach is applied to minimize structural compliance while adhering to constraints on mass, stress, symmetry, and manufacturability. Six mission-specific load cases, including quasistatic surface operations and launch scenarios derived from Miles’ equation, are used to drive the design. The optimization achieves mass reductions of ≈50% for the deployment arm and the rocker support, while preserving mechanical integrity and functional interfaces. Post-optimization validation through finite element analysis confirms that the optimized designs meet all structural performance criteria. Prototypes are fabricated via fused deposition modeling to assess manufacturability and assembly integration, paving the way for future metal AM using aerospace-grade alloys. The results demonstrate a simulation-driven workflow that applies LSB topology optimization with additive manufacturing constraints to mission-specific load cases, integrating European Cooperation for Space Standardization compliant verification and manufacturability to develop structurally efficient rover suspension components.

Electrospinning is a versatile technique for producing polymer nanofibrous fabrics with enhanced functionalities, making it attractive for next-generation respiratory protection. A major limitation of electrospun filters designed for submicron aerosol capture at ≥99.99% efficiency is their comparatively high breathing resistance relative to conventional glass fiber and expanded polytetrafluoroethylene (ePTFE) media. To address this limitation, this study introduces micropleated filters made by multiple-jet needleless electrospinning, where nanofibers are deposited onto uniaxially prestretched textile substrates. Upon release, the substrates contracted to their original dimensions, forming densely packed micro-pleats that increased the effective surface area without altering the overall filter size. Prestretching the substrate to 225% prior to nanofiber deposition produced a twofold increase in quality factor compared with nanofiber mats deposited on unstretched substrates, driven by improved submicron aerosol filtration and reduced pressure drop. The micro-pleated filters achieved quality factors exceeding 0.26 Pa⁻¹, comparable to high-performance ePTFE-based military gas mask filters and more than three times higher than glass fiber filters. The micropleated filters also outperformed ePTFE filters in capturing and releasing aerosolized MS2 bacteriophage. These findings demonstrate that micropleated electrospun filters offer a promising pathway toward high-efficiency, multifunctional filtration systems applicable to defense, healthcare, and environmental protection.

This study examines the impact of ball milling control agents on the microstructure, tensile strength, and tribological properties of CoCrFeNi–Nb high-entropy alloys (HEAs) fabricated via spark plasma sintering. The incorporation of Nb facilitates the formation of a Laves hard phase within the CoCrFeNi HEA matrix. At the same time, the addition of 0.1%wt stearic acid significantly enhances the dispersion of the Laves phase and tensile strength. Friction and wear tests demonstrate a notable enhancement in the wear resistance of the material upon the addition of Nb. Specifically, the wear rate decreases progressively from 0.342 × 10⁻³ mm³ (N m⁻¹) in the absence of Nb doping to 0.213 × 10⁻³ mm³ (N m⁻¹) when doped with 7%wt Nb. For the CoCrFeNi alloy, significant fluctuations in the friction coefficient are observed at 200 r, with abrasive wear being the predominant wear mechanism. As the rotational speed and load increase, the friction coefficient stabilizes, and the wear mechanism transitions from abrasive wear to oxidative wear and adhesive wear. For the CoCrFeNiNbx HEA, the fluctuation amplitude of the friction coefficient increases with higher Nb content, whereas the wear rate decreases. The predominant wear mechanism in the CoCrFeNiNb HEA shifts from abrasive wear in the absence of Nb to adhesive wear.

Indium nitride (InN) has garnered significant attention for high-speed semiconductor devices. However, its inherently nonlayered crystal structure poses a significant challenge for the integration into emerging 2D material systems. Here, the article reports the synthesis of ultrathin polycrystalline InN film and its potential applications in light sensing. The synthesis involves the ammonolysis of indium oxide layers that were squeeze-printed from liquid indium. The intermediate bromination facilitates the transformation into crystalline InN nanosheets characterized by a thickness of ≈47 nm and an optical bandgap around 1.35 eV. The photodetectors designed on ultrathin InN films exhibit a responsivity (R_λ) of 2.11 A·W⁻¹, an external quantum efficiency (EQE) of 4.39 × 10²%, and a detectivity (D*) of 6.5 × 10¹¹ Jones under 365 nm (≈1.0 mW cm⁻², bias = 1 V), comparable to that of other InN materials prepared by MBE, MOCVD, or RF sputtering. In addition, the image reproduction capability of ultrathin InN photodetectors is showcased on a single-pixel imaging platform (excited by a 360 nm laser, 1 V), highlighting the potential for high-precision optical imaging applications. This cost-effective method using liquid metal for the synthesis of ultrathin/polycrystalline InN films offers a promising strategy for integrating industrially important III nitride semiconductors into the future atomically thin systems.

To investigate the effect of cell orientations on the compressive properties of Kelvin foams and compare them with Weaire–Phelan (W-P) foams, a semi-closed-cell Kelvin foam with a relative density (ρ_r) of 20% is 3D printed, followed by a quasi-static compression experiment to validate the ABAQUS model. Subsequently, ABAQUS is performed to analyze the compression behaviors of Kelvin foams with different cell orientations and ρ_r, and W-P foams with various ρ_r. The results indicate that compressive strength (σ_pk) of Kelvin/W-P foams is primarily governed by the number of vertical faces in unit cells, as these faces bear the primary load during service. Energy absorption (EA) is influenced not only by vertical faces but also by the cells′ deformation modes and stacking configuration. At low ρ_r, the W-P foams exhibit the highest EA due to the complex spatial distribution of cell faces and densely packed stacking of unit cells. With increasing ρ_r, Kelvin foams with various cell orientations gradually exhibit more EA than those of W-P foams, attributed to transitions in cell deformation mechanisms and stacking patterns. This article not only advances the modeling and fabrication of Kelvin/W-P lattice structures but also provides mechanical insights into the evolutionary advantages of foam self-organization.

This study introduces a novel auxetic metamaterial structure specifically engineered for protective sports equipment through a parametric design and additive manufacturing approach. Drawing inspiration from the intricate patterns of traditional Persian Lori rugs, a reentrant tubular lattice is conceived as a three-dimensional metamaterial capable of exhibiting a tunable negative Poisson's ratio. The structure is fabricated using high-resolution digital light processing (DLP) 3D printing with an ABS-like photopolymer, enabling precise reproduction of the complex geometry. Systematic variation of two key geometric parameters, wall thickness (0.8, 1.0, 1.2 mm) and cell width (2.75, 4.0, 5.25 mm), allowed rigorous parametric control of mechanical behavior. Combined finite-element analysis and experimental compression testing verified exceptional tunability in stiffness, energy absorption, and Poisson's ratio, which ranged from −1.09 to −2.3. The configuration with 1.2 mm thickness and 5.25 mm width demonstrated the highest stiffness and impact-energy absorption, highlighting its potential for helmets, elbow pads, and similar high-impact gear. The integration of culturally inspired geometry, metamaterial design principles, and precision DLP 3D printing establishes a unique pathway for next-generation protective equipment, showcasing how parametric control of auxetic metamaterials can simultaneously achieve lightweight construction, superior energy dissipation, and enhanced user comfort.

Developing brake pad friction materials is critical to enhancing the automotive brake system's performance. Solid lubricants play a crucial role in reducing wear and maintaining friction under demanding conditions. While molybdenum disulfide (MoS₂) remains widely used, recent progress in 2D materials has opened new possibilities. Among these, titanium-based MXenes (Ti₃C₂T_x) have emerged as promising candidates due to their mechanical strength, thermal resilience, and inherent self-lubricating properties. This study presents the first comprehensive evaluation of Ti₃C₂T_x and MoS₂ as a solid lubricant in automotive brake pad composites. A fixed matrix composition of steel fibers, barium sulfate, phenol-formaldehyde resin, and iron oxide is maintained across three formulations: a MoS₂-based, a Ti₃C₂T_x-based, and a hybrid combining both additives. The samples are fabricated adopting powder metallurgical techniques. Samples evaluation is conducted to analyze their thermal, mechanical, physical, and tribological properties. Microstructural analyses are performed using scanning electron microscopy and energy-dispersive X-ray spectroscopy. Tribological performance is assessed through pin-on-disk against a gray cast iron disk. Results show that Ti₃C₂T_x-containing composites excel in all aspects compared to MoS₂. The hybrid formulation composite reduces specific wear rate by 16.5%, while the Ti₃C₂T_x-only composite achieves a 48.5% reduction relative to the MoS₂ composite.

Solar-driven photocatalytic CO₂ conversion is a promising method for tackling the energy crisis and reducing CO₂ emissions. In this work, a GaN/ZnIn₂S₄ (ZIS) heterojunction photoanode is constructed to elucidate how the ZIS morphology and the concentration used during spin-coating influence photocatalytic CO₂ reduction performance. The results show that the nanoflower-like ZIS (ZIS-NF) significantly enhances light-harvesting capability and charge-separation efficiency due to its high specific surface area of 218.401 m² g⁻¹ and its mesoporous structure. As a result, the GaN/ZIS-NF heterojunction delivers a photocurrent density of 0.32 mA cm⁻², while the CO and H₂ production rates increase by 2.6-fold and 3.25-fold, respectively, compared with bare GaN. Further optimization of the ZIS-NF spin-coating concentration reveals that a 1:10 ratio yields the highest photocurrent density of 0.37 mA cm⁻², with CO and H₂ production enhanced by 5.28-fold and 4.62-fold, respectively, over bare GaN. This study provides meaningful guidance for designing high-performance GaN-based photoanodes to improve photocatalytic CO₂ reduction efficiency.

Lattice materials exhibit excellent impact-resistance properties, which are advanced multifunctional materials with great design potential. In this study, by introducing the two-phase strengthening mechanism of composite materials, the biphasic stretching-bending synergistic lattices (BSBSLs), which contain matrix phase cells and enhanced phase backbone cells, are constructed, and their dynamic compression response and energy absorption characteristics are investigated by numerical simulation. Additionally, the effect of the height and density distribution of cells on energy absorption (EA) is analyzed. Finally, to further improve the performance of specific energy absorption (SEA), optimization models of uniform and hierarchical BSBSLs are established. The results indicate that, at the same relative density, compared with stretching-bending synergistic lattices (SBSLs), the specific strength and SEA of BSBSLs have increased by 49.7% and 57.59% respectively. Compared with the initial structure, for uniform BSBSLs, when the overall relative density remains unchanged and varies from 10% to 70%, the SEA of the optimal structure has increased by 288% and 373% respectively; for hierarchical BSBSLs, when the relative density varies from 10% to 70%, the SEA of the optimal structure has increased by 404%. This research provides a reference for the design of dynamic compression response and optimization design of multilayer lattice structures.