Advanced Engineering Materials最新文献

This study investigates the mechanical performance of three auxetic structures: re-entrant, re-entrant-star hybrid, and S-shape, to identify the most effective design for high-impact applications. Among these, the re-entrant-star hybrid structure demonstrates superior specific energy absorption (SEA), achieving 0.92 ± 0.12 J g⁻¹, attributed to its combination of re-entrant and star-shaped elements, which enhances both energy dissipation and structural integrity. In contrast, the re-entrant and S-shaped structures recorded SEAs of 0.80 ± 0.02 and 0.19 ± 0.05 J g⁻¹, respectively. The hybrid structure also exhibits the highest crush force efficiency (CFE) and equivalent plateau stress (EPS), highlighting its ability to maintain consistent load-bearing capacity and to sustain stress during compression. Flexural and impact tests further validate the hybrid structure's performance, with notable improvements in bending strength and impact resistance. To further enhance its performance, finite element analysis (FEA) simulations are conducted to optimize geometric parameters, specifically strut thickness and inclination angle, to maximize mechanical performance. Postoptimization, the SEA of the re-entrant-star structure increases by 449%, EPS by 3400%, and in-plane flexural modulus by 514%. These results demonstrate the effectiveness of optimizing geometric parameters to maximize the mechanical performance of auxetic structures for applications requiring high-energy absorption.

This article explores the tribological behaviors of Zr_46.5Cu₄₅Al₇Ti_1.5 bulk metallic glass (BMG) during linear reciprocating sliding against WC ball under different loads. The time-dependent coefficient of friction indicates the presence of a significant “Running-in” stage during wear tests, with the duration of this stage extending as the normal load increases. The structural characteristics of the samples are examined using X-ray diffraction, which confirmed their noncrystalline nature. The wear surfaces and debris of the BMG and WC ball are analyzed using scanning electron microscopy coupled with energy-dispersive spectroscopy. The results demonstrate that the predominant wear mechanisms at low loads are abrasive and adhesive wear, accompanied by minimal oxidative wear. Under high loads, adhesive and oxidative wear dominate. A high wear rate is associated with adhesive wear, whereas a low wear rate is linked to oxidative wear.

This study addresses the issues of coarse-grain size in the core and radial microstructural inhomogeneity of extruded magnesium alloy rods by proposing a rotational-bending coupled deformation process for regulation. Combining finite element simulations with experiments, the effects of bending angle (155°–175°), rotational cycle (1–120 r), and deformation temperature (200–350 °C) on the deformation behavior and microstructural properties of the rods are analyzed. Results demonstrate that the established finite element model accurately predicts stress/strain field distributions. The accumulated plastic strain in the bar exhibits a gradient distribution from surface to core, with both the gradient span and circumferential uniformity improving as the bending angle, rotation cycle, and temperature increase. Temperature significantly influences microstructural evolution. At 200 °C, twinning predominates. Upon further heating, dynamic recrystallization intensifies, resulting in pronounced equiaxed grains in the core. Under optimized conditions of θ = 155° and N = 120 revolutions, grain refinement achieves optimal results, reducing grain size by half compared to the initial state. This process enables continuous gradient control of microstructure, significantly enhances overall microhardness, and improves gradient continuity in hardness distribution, providing a novel approach for fabricating gradient-structured magnesium alloy rods.

The rapid advancement of microelectronic technologies and smart devices has intensified the need for electromagnetic interference (EMI) shielding materials that are not only efficient and multifunctional, but also sustainable and environmentally friendly. Biomass-based materials, with their unique hierarchical architectures, diverse chemical functionalities, and inherent renewability, have emerged as promising candidates in this domain. This review provides a systematic overview of the structural characteristics and functional advantages of biomass-derived EMI shielding composite materials, with an emphasis on shielding mechanisms and performance optimization strategies. Particular attention is given to the synergistic integration of various conductive components (e.g., MXene, carbon, metals, and conductive polymers) with rational structural designs (such as film, porous frameworks, and bicontinuous architectures), which enable the development of materials with enhanced shielding efficiency and structural stability. Finally, the outlook outlines key future directions, including sustainable filler development, intelligent shielding architectures, green scalable fabrication, and data-driven materials design. This work offers comprehensive insights to guide the innovation of next-generation high-performance, ecofriendly EMI shielding materials for advanced electronic and communication applications.

The development of magnesium-based metal matrix composites (MMCs) for biomedical implants is often hindered by the high cost and time associated with conventional trial-and-error optimization. In this study, we present an explainable ML framework to accelerate the design and prediction of mechanical performance in magnesium-based alloys reinforced with HAP and a hybrid system of HAP and GNP. An ensemble of regression models was evaluated, with XGBoost demonstrating superior generalization capability, achieving R² values of 0.955 for yield strength, 0.954 for ultimate tensile strength, and 0.939 for % elongation. To ensure model transparency, SHAP was integrated to interpret feature contributions at both global and local levels. The analysis revealed that ECAP and weight percentage of reinforcement are the most influential factors, with nonlinear optimal ranges identified for weight percentage of reinforcement, particle size, and reinforcement. Guided by these insights, a new AZ91-matrix composite incorporating a hybrid HAP and GNP reinforcement was designed and fabricated via stir casting. Experimental validation demonstrated excellent agreement between model predictions and measured mechanical responses, confirming the high-fidelity framework. Residual analysis confirmed model robustness and homoscedasticity. This work establishes a transparent, data-driven framework that bridges predictive modeling with physical interpretability, enabling the rational design of high-performance, biodegradable implants with reduced reliance on extensive experimentation.

Herein, the chemical coprecipitation process is used to synthesize M-type strontium hexaferrite (SrFe₁₂O₁₉, SrM) and manganese-substituted strontium hexaferrite (SrFe_12−xMn_xO₁₉, SrMnM), with x = 0.36, 0.60, and 0.84. The primary crystal phase is hexagonal with space group P6₃/mmc, and small traces of secondary phases, identified as hematite (α-Fe₂O₃) and halite (NaCl), are detected by X-ray diffraction analysis. Also, Rietveld refinement methods are used to extract information on the phase composition and the average bond lengths and angles from the refined crystal structure parameters. Fourier transform infrared analysis indicates the presence of distinctive absorption bands related to the vibration FeO and FeOFe. A Thermogravimetric analysis determines the optimal temperature for developing the M-type hexaferrite phase. Magnetic hysteresis loops show that magnetic parameters increases with increasing manganese substitution. Also, the single-domain behavior of the synthesized material is confirmed by the M_r/M_s ratios. The enhanced magnetic properties of the synthesized materials offer promising potential for use in permanent magnets and magnetic recording applications.

Zr₅₅Cu₃₀Al₁₀Ni₅ amorphous coatings were deposited onto AISI 1010 carbon steel substrates via high-energy ball milling of as-spun metallic glass ribbons. Their tribological performance under dry sliding was evaluated using a reciprocating pin-on-plate setup and compared with both the crystalline alloy and the bare carbon steel. The crystalline Zr₅₅Cu₃₀Al₁₀Ni₅ (430 HV_0.3) alloy exhibited the lowest coefficient of friction (COF ≈ 0.28), whereas the amorphous coating achieved superior hardness (550 HV_0.3), three times higher than the substrate (162 HV_0.3), with a COF of ≈0.39. The amorphous coating showed a specific wear rate (≈10⁻⁴ mm³ N⁻¹ m⁻¹), an order of magnitude lower than the carbon steel (≈10⁻³ mm³ N⁻¹ m⁻¹). Wear mechanisms differed: the amorphous coating underwent mainly adhesive and delamination wear with minor abrasive and oxidative contributions, while the crystalline alloy experienced mixed abrasive-adhesive wear with mild oxidation. These results highlight the promise of mechanically deposited Zr-based amorphous coatings as effective wear-resistant surfaces for steel substrates.

A suitable combination of mechanical, topographical, and biological responses enhances implant-bone interaction and ensures successful patient outcomes. In this regard, body-centered-cubic (BCC) and cubic lattices are designed and fabricated with porosity ranging between 50% and 80%. Finite element analysis and uniaxial tensile tests are conducted to evaluate the mechanical properties of the lattices. Roughness and wettability are studied to evaluate the topographical properties. The biological behavior is studied through in vitro response of MG-63 cells on scaffolds after 1, 4, and 7 d. Two types of surfaces, as-fabricated and heat-treated, are prepared for roughness, wettability measurements, and in vitro experiments. The mechanical tests reveal that BCC and cubic lattices can mimic femoral bone properties at 60% and 65% porosity, respectively. The R_a values are found to be ≈12 μm for the as-produced and 1.2 to 3 μm for the heat-treated lattices. Hydrophobic and super-hydrophilic natures have been observed with as-fabricated and heat-treated scaffolds during the wettability experiment, respectively. The in vitro response shows the most favorable cell proliferations in heat-treated cubic lattices compared to other scaffolds. Based on these observations, a novel porous short hip stem featuring a cubic porous structure has been designed and successfully fabricated using selective laser melting.

Accurate and decoupled detection of normal and shear forces is essential for next-generation tactile systems but remains challenging due to structural limitations and material constraints in existing flexible sensors. To address this, a biomimetic trilayer flexible sensor that integrates a rigid microcolumn and dual piezoresistive layers of liquid metal is designed, enabling simultaneous detection of pressure and shear strain. A scalable spray-coating process is developed using ethanol- and iron-modified liquid metal ink, which improves adhesion to PDMS and prevents nozzle corrosion. Guided by finite element simulations (ABAQUS controlled via Python), the sensor geometry is optimized for enhanced directional decoupling. Experimental results demonstrate excellent linearity (R² > 0.996) across a wide pressure range (70.77–533.61 kPa), rapid response, and strong durability under repeated loading. This work provides a robust and scalable approach for fabricating high-performance, multimodal flexible sensors with broad potential in robotic e-skins, industrial inspection, and interactive electronics.

The aim of this study is to explore the internal damage mechanisms of AlSi12 metal matrix syntactic foam (MMSF) with embedded ceramic hollow spheres (CHSs) to understand the damage behavior during compressive loading. To achieve this goal, in situ synchrotron X-ray tomography is used. A qualitative and quantitative assessment of the initiation and gradual collapse of matrix, filler material, and pores is presented. The imaging-based investigation provided detailed visualization and tracking of failure mechanisms of the MMSF, with emphasis on the collapse of hollow spheres at the microstructural level. The structural parameters describing performance limits are experimentally determined and correlated with internal mechanisms. It is concluded that a homogeneous distribution of the second-phase filler material results in a sequential collapse in a localized region; this leads to controlled and predictable energy absorption. The CHSs rupture is found to be location dependent within the localized shear band region, with spheres of all diameters failing to a similar extent. The results from this work can be used to train or validate predictive models of MMSFs deformed under compressive loading conditions by correlating the 3D damage progression with the overall mechanical response.