Materials

19 pages, 1418 KiB

Open AccessArticle

Static and Vibration Analysis of Imperfect Thermoelastic Laminated Plates on a Winkler Foundation

by Jiahuan Liu, Yunying Zhou, Yipei Meng, Hong Mei, Zhijie Yue and Yan Liu

Materials 2025, 18(15), 3514; https://doi.org/10.3390/ma18153514 (registering DOI) - 26 Jul 2025

This study introduces an analytical framework that integrates the state-space method with generalized thermoelasticity theory to obtain exact solutions for the static and dynamic behaviors of laminated plates featuring imperfect interfaces and resting on a Winkler foundation. The model comprehensively accounts for the [...] Read more.

This study introduces an analytical framework that integrates the state-space method with generalized thermoelasticity theory to obtain exact solutions for the static and dynamic behaviors of laminated plates featuring imperfect interfaces and resting on a Winkler foundation. The model comprehensively accounts for the foundation-structure interaction, interfacial imperfection, and the coupling between the thermal and mechanical fields. A parametric analysis explores the impact of the dimensionless foundation coefficient, interface flexibility coefficient, and thermal conductivity on the static and dynamic behaviors of the laminated plates. The results indicate that a lower foundation stiffness results in higher sensitivity of structural deformation with respect to the foundation parameter. Furthermore, an increase in interfacial flexibility significantly reduces the global stiffness and induces discontinuities in the distribution of stress and temperature. Additionally, thermal conductivity governs the continuity of interfacial heat flux, while thermo-mechanical coupling amplifies the variations in specific field variables. The findings offer valuable insights into the design and reliability evaluation of composite structures operating in thermally coupled environments. Full article

(This article belongs to the Section Materials Simulation and Design)

18 pages, 2518 KiB

Open AccessArticle

NiO/TiO₂ p-n Heterojunction Induced by Radiolysis for Photocatalytic Hydrogen Evolution

by Ana Andrea Méndez-Medrano, Xiaojiao Yuan, Diana Dragoe, Christophe Colbeau-Justin, José Luis Rodríguez López and Hynd Remita

Materials 2025, 18(15), 3513; https://doi.org/10.3390/ma18153513 (registering DOI) - 26 Jul 2025

Abstract

Titanium dioxide (TiO₂), a widely used semiconductor in photocatalysis owing to its adequate potential for water hydrolysis, chemical stability, low toxicity, and low cost. However, its efficiency is limited by fast charge-carrier recombination and poor visible light absorption. Coupling TiO₂ [...] Read more.

Titanium dioxide (TiO₂), a widely used semiconductor in photocatalysis owing to its adequate potential for water hydrolysis, chemical stability, low toxicity, and low cost. However, its efficiency is limited by fast charge-carrier recombination and poor visible light absorption. Coupling TiO₂ with a p-type semiconductor, such as nickel oxide (NiO), forming a p-n heterojunction, decreases the recombination of charge carriers and increases photocatalytic activity. In this work, the surface of TiO₂ modified with NiO nanoparticles (NPs) induced by radiolysis for photocatalytic hydrogen production was studied. The photocatalytic activity of NiO/TiO₂ was evaluated using methanol as a hole scavenger under UV–visible light. All modified samples presented superior photocatalytic activity compared to bare TiO₂. The dynamics of the charge carriers, a key electronic phenomenon in photocatalysis, was investigated by time-resolved microwave conductivity (TRMC). The results highlight the crucial role of Ni-based NPs modification in enhancing the separation of the charge carrier and activity under UV–visible irradiation. Furthermore, the results revealed that under visible irradiation, NiO-NPs inject electrons into the conduction band of titanium dioxide. Full article

(This article belongs to the Section Advanced Nanomaterials and Nanotechnology)

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26 pages, 8400 KiB

Open AccessArticle

Conceptual Design of a Hybrid Composite to Metal Joint for Naval Vessels Applications

by Man Chi Cheung, Nenad Djordjevic, Chris Worrall, Rade Vignjevic, Mihalis Kazilas and Kevin Hughes

Materials 2025, 18(15), 3512; https://doi.org/10.3390/ma18153512 (registering DOI) - 26 Jul 2025

Abstract

This paper describes the development of a new hybrid composite for the metal joints of aluminium and glass fibre composite adherents. The aluminium adherend is manufactured using friction stir-formed studs that are inserted into the composite adherend in the through-thickness direction during the [...] Read more.

This paper describes the development of a new hybrid composite for the metal joints of aluminium and glass fibre composite adherents. The aluminium adherend is manufactured using friction stir-formed studs that are inserted into the composite adherend in the through-thickness direction during the composite manufacturing process, where the dry fibres are displaced to accommodate the studs before the resin infusion process. The materials used were AA6082-T6 aluminium and plain-woven E-glass fabric reinforced epoxy, with primary applications in naval vessels. This joining approach offers a cost-effective solution that does not require complicated onsite welding. The joint design was developed based on a simulation test program with finite element analysis, followed by experimental characterisation and validation. The design solution was analysed in terms of the force displacement response, sequence of load transfer, and characterisation of the joint failure modes. Full article

(This article belongs to the Section Advanced Composites)

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5 pages, 330 KiB

Open AccessEditorial

Advanced Materials for Solar Energy Utilization

by Xingwang Zhu and Tongming Su

Materials 2025, 18(15), 3511; https://doi.org/10.3390/ma18153511 (registering DOI) - 26 Jul 2025

Abstract

In the context of sustainable societal development, exploring novel, environmentally sustainable energy sources has emerged as a pivotal global concern [...] Full article

(This article belongs to the Special Issue Advanced Materials for Solar Energy Utilization)

29 pages, 4258 KiB

Open AccessReview

Corrosion Performance of Atmospheric Corrosion Resistant Steel Bridges in the Current Climate: A Performance Review

by Nafiseh Ebrahimi, Melina Roshanfar, Mojtaba Momeni and Olga Naboka

Materials 2025, 18(15), 3510; https://doi.org/10.3390/ma18153510 (registering DOI) - 26 Jul 2025

Abstract

Weathering steel (WS) is widely used in bridge construction due to its high corrosion resistance, durability, and low maintenance requirements. This paper reviews the performance of WS bridges in Canadian climates, focusing on the formation of protective patina, influencing factors, and long-term maintenance [...] Read more.

Weathering steel (WS) is widely used in bridge construction due to its high corrosion resistance, durability, and low maintenance requirements. This paper reviews the performance of WS bridges in Canadian climates, focusing on the formation of protective patina, influencing factors, and long-term maintenance strategies. The protective patina, composed of stable iron oxyhydroxides, develops over time under favorable wet–dry cycles but can be disrupted by environmental aggressors such as chlorides, sulfur dioxide, and prolonged moisture exposure. Key alloying elements like Cu, Cr, Ni, and Nb enhance corrosion resistance, while design considerations—such as drainage optimization and avoidance of crevices—are critical for performance. The study highlights the vulnerability of WS bridges to microenvironments, including de-icing salt exposure, coastal humidity, and debris accumulation. Regular inspections and maintenance, such as debris removal, drainage system upkeep, and targeted cleaning, are essential to mitigate corrosion risks. Climate change exacerbates challenges, with rising temperatures, altered precipitation patterns, and ocean acidification accelerating corrosion in coastal regions. Future research directions include optimizing WS compositions with advanced alloys (e.g., rare earth elements) and integrating climate-resilient design practices. This review highlights the need for a holistic approach combining material science, proactive maintenance, and adaptive design to ensure the longevity of WS bridges in evolving environmental conditions. Full article

(This article belongs to the Special Issue Rapid Inspection, Evaluation, and Repair Materials on Transportation Infrastructures)

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28 pages, 4633 KiB

Open AccessReview

Innovative Strategies in Hernia Mesh Design: Materials, Mechanics, and Modeling

by Evangelia Antoniadi, Nuno Miguel Ferreira, Maria Francisca Vaz, Marco Parente, Maria Pia Ferraz and Elisabete Silva

Materials 2025, 18(15), 3509; https://doi.org/10.3390/ma18153509 (registering DOI) - 26 Jul 2025

Abstract

Hernia is a physiological condition that significantly impacts patients’ quality of life. Surgical treatment for hernias often involves the use of specialized meshes to support the abdominal wall. While this method is highly effective, it frequently leads to complications such as pain, infections, [...] Read more.

Hernia is a physiological condition that significantly impacts patients’ quality of life. Surgical treatment for hernias often involves the use of specialized meshes to support the abdominal wall. While this method is highly effective, it frequently leads to complications such as pain, infections, inflammation, adhesions, and even the need for revision surgeries. According to the Food and Drug Administration (FDA), hernia recurrence rates can reach up to 11%, surgical site infections occur in up to 21% of cases, and chronic pain incidence ranges from 0.3% to 68%. These statistics highlight the urgent need to improve mesh technologies to minimize such complications. The design and material composition of meshes are critical in reducing postoperative complications. Moreover, integrating drug-eluting properties into the meshes could address issues like infections and inflammation by enabling localized delivery of antibiotics and anti-inflammatory agents. Mesh design is equally important, with innovative structures like auxetic designs offering enhanced mechanical properties, flexibility, and tissue integration. These advanced designs can distribute stress more evenly, reduce fatigue, and improve performance in areas subjected to high pressures, such as during intense coughing, sneezing, or heavy lifting. Technological advancements, such as 3D printing, enable the precise fabrication of meshes with tailored designs and properties, providing new opportunities for innovation. By addressing these challenges, the development of next-generation mesh implants has the potential to reduce complications, improve patient outcomes, and significantly enhance quality of life for individuals undergoing hernia repair. Full article

(This article belongs to the Section Biomaterials)

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25 pages, 4401 KiB

Open AccessArticle

Impact of High Energy Milling and Mineral Additives on a Carbonate–Quartz–Apatite System for Ecological Applications

by Vilma Petkova, Katerina Mihaylova, Ekaterina Serafimova, Rositsa Titorenkova, Liliya Tsvetanova and Andres Trikkel

Materials 2025, 18(15), 3508; https://doi.org/10.3390/ma18153508 (registering DOI) - 26 Jul 2025

Abstract

In this study, high-energy milled (HEM) samples of natural phosphorites from Estonian deposits were investigated. The activation was performed via planetary mill with Cr-Ni grinders with a diameter of 20 mm. This method is an ecological alternative, since it eliminates the disadvantages of [...] Read more.

In this study, high-energy milled (HEM) samples of natural phosphorites from Estonian deposits were investigated. The activation was performed via planetary mill with Cr-Ni grinders with a diameter of 20 mm. This method is an ecological alternative, since it eliminates the disadvantages of conventional acid methods, namely the release of gaseous and solid technogenic products. The aim of the study is to determine the changes in the structure to follow the solid-state transitions and the isomorphic substitutions in the anionic sub-lattice in the structure of the main mineral apatite in the samples from Estonia, under the influence of HEM activation. It is also interesting to investigate the influence of HEM on structural-phase transformations on the structure of impurity minerals-free calcite/dolomite, pyrite, quartz, as well as to assess their influence on the thermal behavior of the main mineral apatite. The effect of HEM is monitored by using a complex of analytical methods, such as chemical analysis, powder X-ray diffraction (PXRD), wavelength-dispersive X-ray fluorescence (WD-XRF) analysis, and Fourier-transformed infrared (FTIR) analysis. The obtained results prove the correlation in the behavior of the studied samples with regard to their quartz content and bonded or non-bonded carbonate ions. After HEM activation of the raw samples, the following is established: (i) anionic isomorphism with formation of A and A-B type carbonate-apatites and hydroxyl-fluorapatite; (ii) solid-phase synthesis of calcium orthophosphate-CaHPO₄ (monetite) and dicalcium diphosphate-β-Ca₂P₂O₇; (iii) enhanced chemical reactivity by approximately three times by increasing the solubility via HEM activation. The dry milling method used is a suitable approach for solving technological projects to improve the composition and structure of soils, increasing soil fertility by introducing soluble forms of calcium phosphates. It provides a variety of application purposes depending on the composition, impurities, and processing as a soil improver, natural mineral fertilizer, or activator. Full article

(This article belongs to the Special Issue Advances in Rock and Mineral Materials—Second Edition)

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24 pages, 3361 KiB

Open AccessArticle

Elastic–Plastic Analysis of Asperity Based on Wave Function

by Zijian Xu, Min Zhu, Wenjuan Wang, Ming Guo, Shengao Wang, Xiaohan Lu and Ziwei Li

Materials 2025, 18(15), 3507; https://doi.org/10.3390/ma18153507 (registering DOI) - 26 Jul 2025

Abstract

This paper proposes an improved wave function asperity elastic–plastic model. A cosine function that could better fit the geometric morphology was selected to construct the asperity, the elastic phase was controlled by the Hertz contact theory, the elastoplastic transition phase was corrected by [...] Read more.

This paper proposes an improved wave function asperity elastic–plastic model. A cosine function that could better fit the geometric morphology was selected to construct the asperity, the elastic phase was controlled by the Hertz contact theory, the elastoplastic transition phase was corrected by the hyperbolic tangent function, and the fully plastic phase was improved by the projected area theory. The model broke through the limitations of the spherical assumption and was able to capture the stress concentration and plastic flow phenomena. The results show that the contact pressure in the elastic phase was 22% higher than that of the spherical shape, the plastic strain in the elastoplastic phase was 52% lower than that of the spherical shape, and the fully plastic phase reduced the contact area error by 20%. The improved hyperbolic tangent function eliminated the unphysical oscillation phenomenon in the elastoplastic phase and ensured the continuity and monotonicity of the contact variables, with an error of <5% from the finite element analysis. Meanwhile, extending the proposed model, we developed a rough surface contact model, and it was verified that the wavy asperity could better match the mechanical properties of the real rough surface and exhibited progressive stiffness reduction during the plastic flow process. The model in this paper can provide a theoretical basis for predicting stress distribution, plastic evolution, and multi-scale mechanical behavior in the connection interface. Full article

(This article belongs to the Section Materials Simulation and Design)

21 pages, 690 KiB

Open AccessArticle

Analysis of the Differences Resulting from the Determination of Langmuir Isotherm Coefficients from Linear and Non-Linear Forms—A Case Study

by Joanna Lach

Materials 2025, 18(15), 3506; https://doi.org/10.3390/ma18153506 (registering DOI) - 26 Jul 2025

Abstract

The sorption process is most commonly described by Langmuir isotherms, which can be calculated from either a non-linear form or various linear forms. Despite the fact that the non-linear model is now preferred, articles using linear models continue to be submitted to journals. [...] Read more.

The sorption process is most commonly described by Langmuir isotherms, which can be calculated from either a non-linear form or various linear forms. Despite the fact that the non-linear model is now preferred, articles using linear models continue to be submitted to journals. On the basis of 68 isotherms, it was found that the linear Hanes–Woolf model (the most commonly used) gives the most similar q_m and K_L values to the non-linear model. The largest differences were obtained by determining the isotherm from the non-linear and linear forms of the Lineweaver–Burk model (this is the model often used by researchers). The evaluation of isotherms should not be performed solely on the basis of the coefficient of determination R², which was intended for linear equations. Statistical measures such as the mean relative error, sum of squares of errors, chi-square statistic, sum of absolute errors, hybrid fractional error function, mean squared error were analysed. On the basis of the coefficient of determination, the Hanes–Woolf linear model was found to best describe the actual results, and on the basis of the other statistical measures, the isotherm determined from the non-linear form was found to be the best fit for the study. Full article

(This article belongs to the Special Issue Adsorption Materials and Their Applications (2nd Edition))

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14 pages, 2733 KiB

Open AccessArticle

Study on Microstructure and Wear Resistance of Multi-Layer Laser Cladding Fe901 Coating on 65 Mn Steel

by Yuzhen Yu, Weikang Ding, Xi Wang, Donglu Mo and Fan Chen

Materials 2025, 18(15), 3505; https://doi.org/10.3390/ma18153505 (registering DOI) - 26 Jul 2025

Abstract

65 Mn is a high-quality carbon structural steel that exhibits excellent mechanical properties and machinability. It finds broad applications in machinery manufacturing, agricultural tools, and mining equipment, and is commonly used for producing mechanical parts, springs, and cutting tools. Fe901 is an iron-based [...] Read more.

65 Mn is a high-quality carbon structural steel that exhibits excellent mechanical properties and machinability. It finds broad applications in machinery manufacturing, agricultural tools, and mining equipment, and is commonly used for producing mechanical parts, springs, and cutting tools. Fe901 is an iron-based alloy that exhibits excellent hardness, structural stability, and wear resistance. It is widely used in surface engineering applications, especially laser cladding, due to its ability to form dense and crack-free metallurgical coatings. To enhance the surface hardness and wear resistance of 65 Mn steel, this study employs a laser melting process to deposit a multi-layer Fe901 alloy coating. The phase composition, microstructure, microhardness, and wear resistance of the coatings are investigated using X-ray diffraction (XRD), optical microscopy, scanning electron microscopy (SEM), Vickers hardness testing, and friction-wear testing. The results show that the coatings are dense and uniform, without visible defects. The main phases in the coating include solid solution, carbides, and α-phase. The microstructure comprises dendritic, columnar, and equiaxed crystals. The microhardness of the cladding layer increases significantly, with the multilayer coating reaching 3.59 times the hardness of the 65 Mn substrate. The coatings exhibit stable and relatively low friction coefficients ranging from 0.38 to 0.58. Under identical testing conditions, the wear resistance of the coating surpasses that of the substrate, and the multilayer coating shows better wear performance than the single-layer one. Full article

(This article belongs to the Section Advanced Composites)

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32 pages, 4418 KiB

Open AccessArticle

The Use of Chitosan/Perlite Material for Microbial Support in Anaerobic Digestion of Food Waste

by Agnieszka A. Pilarska, Anna Marzec-Grządziel, Małgorzata Makowska, Alicja Kolasa-Więcek, Ranjitha Jambulingam, Tomasz Kałuża and Krzysztof Pilarski

Materials 2025, 18(15), 3504; https://doi.org/10.3390/ma18153504 (registering DOI) - 26 Jul 2025

Abstract

This study aims to evaluate the effect of adding a chitosan/perlite (Ch/P) carrier to anaerobic digestion (AD) on the efficiency and kinetics of the process, as well as the directional changes in the bacterial microbiome. A carrier with this composition was applied in [...] Read more.

This study aims to evaluate the effect of adding a chitosan/perlite (Ch/P) carrier to anaerobic digestion (AD) on the efficiency and kinetics of the process, as well as the directional changes in the bacterial microbiome. A carrier with this composition was applied in the AD process for the first time. A laboratory experiment using wafer waste (WF) and cheese (CE) waste was conducted under mesophilic conditions. The analysis of physico-chemical properties confirmed the suitability of the tested carrier material for anaerobic digestion. Both components influenced the microstructural characteristics of the carrier: perlite contributed to the development of specific surface area, while chitosan determined the porosity of the system. Using next-generation sequencing (NGS), the study examined how the additive affected the genetic diversity of bacterial communities. Fourier-transform infrared spectroscopy (FTIR) revealed that the degradation rate depended on both the carrier and the substrate type. Consequently, the presence of the carrier led to an increase in the volume of biogas and methane produced. The volume of methane for the wafer waste (WF–control) increased from 351.72 m³ Mg⁻¹ (VS) to 410.74 m³ Mg⁻¹ (VS), while for the cosubstrate sample (wafer and cheese, WFC–control), it increased from 476.84 m³ Mg⁻¹ (VS) to 588.55 m³ Mg⁻¹ (VS). Full article

(This article belongs to the Section Advanced Composites)

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11 pages, 1902 KiB

Open AccessCommunication

Visualization of Light-Impinging Geometry in Nonlinear Photocurrents of Vertical Optoelectronic Devices

by Hacer Koc, Jianbin Chen, Dawei Gu and Mustafa Eginligil

Materials 2025, 18(15), 3503; https://doi.org/10.3390/ma18153503 - 25 Jul 2025

Abstract

Nonlinear photocurrents (NPs) are electrical currents expected to be measured at the electrodes of a device consisting of an active area, sensitive to light, with a higher-order in-electric field where light-impinging geometry (LIG) is the determining factor in the experimental observation. Although the [...] Read more.

Nonlinear photocurrents (NPs) are electrical currents expected to be measured at the electrodes of a device consisting of an active area, sensitive to light, with a higher-order in-electric field where light-impinging geometry (LIG) is the determining factor in the experimental observation. Although the phenomenology of this light–matter interaction is clear for light directed on a lateral device plane with well-defined azimuthal and incidence angles, as well as light polarization angle, it can be quite complicated for a vertical device structure and reconsideration of the expected NP contributions is necessary in the latter case. In this study, we used a visual approach to describe the LIG for vertical device structures using a specific example of a photodiode, and showed that these angles must be redefined, namely, the interchangeability of azimuthal and incidence angles. The influence of device geometry-dependent optical illumination is reflected on the behavior of NP; therefore, the NPs that are known to be forbidden in certain LIGs can be allowed and vice versa. These results pave the way for the utilization of NPs in flexible optoelectronic applications. Full article

(This article belongs to the Special Issue Low-Dimensional Materials for Optoelectronic and Photovoltaic Fundamentals and Applications)

24 pages, 7026 KiB

Open AccessArticle

VAM-Based Equivalent Cauchy Model for Accordion Honeycomb Structures with Zero Poisson’s Ratio

by Yuxuan Lin, Mingfang Chen, Zhenxuan Cai, Zhitong Liu, Yifeng Zhong and Rong Liu

Materials 2025, 18(15), 3502; https://doi.org/10.3390/ma18153502 - 25 Jul 2025

Abstract

The accordion honeycomb has unique deformation characteristics in cellular materials. This study develops a three-dimensional equivalent Cauchy continuum model (3D-ECM) based on the variational asymptotic method (VAM) to efficiently predict the mechanical response of the accordion honeycomb. The accuracy of the 3D-ECM is [...] Read more.

The accordion honeycomb has unique deformation characteristics in cellular materials. This study develops a three-dimensional equivalent Cauchy continuum model (3D-ECM) based on the variational asymptotic method (VAM) to efficiently predict the mechanical response of the accordion honeycomb. The accuracy of the 3D-ECM is validated via quasi-static compression experiments on 3D-printed specimens and detailed 3D finite element simulations (3D-FEM), showing a strong correlation between simulation and experimental data. Parametric analyses reveal that the re-entrant angle, ligament-to-strut length ratio, and thickness ratios significantly affect the equivalent elastic moduli, providing insights into geometric optimization strategies for targeted mechanical performance. Comparative experiments among honeycomb structures with positive, negative, and zero Poisson’s ratios show that the accordion honeycomb achieves superior dimensional stability and tunable stiffness but exhibits lower energy-absorption efficiency due to discontinuous buckling and recovery processes. Further comparison among different ZPR honeycombs confirms that the accordion design offers the highest equivalent modulus in the re-entrant direction. The findings underscore the accordion honeycomb’s promise in scenarios demanding structural reliability, tunable stiffness, and moderate energy absorption. Full article

(This article belongs to the Special Issue Lightweight and High-Strength Sandwich Panel (2nd Edition))

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19 pages, 4710 KiB

Open AccessArticle

A Non-Contact Method of Measuring Capillary Rise Based on the Hygroscopic Expansion of the Material

by Andrzej Kucharczyk, Kamil Pawlik and Mariusz Czabak

Materials 2025, 18(15), 3501; https://doi.org/10.3390/ma18153501 - 25 Jul 2025

Abstract

This paper presents a novel, non-contact method for measuring capillary water uptake in porous materials based on the phenomenon of moisture-induced expansion. The proposed approach establishes a quantitative relationship between the amount of water absorbed by the material and the deformations measured on [...] Read more.

This paper presents a novel, non-contact method for measuring capillary water uptake in porous materials based on the phenomenon of moisture-induced expansion. The proposed approach establishes a quantitative relationship between the amount of water absorbed by the material and the deformations measured on its surface. Digital Image Correlation (DIC) was used to track the displacements of reference points on gypsum specimens during capillary rise. The absorbed water mass was determined from the recorded displacements using a mechanical model that incorporates the moisture expansion coefficient. The method was validated by comparison with conventional continuous gravimetric measurements. The results demonstrate that the displacement-based approach accurately captures the capillary rise process, particularly in the initial phase, where the gravimetric method suffers from significant measurement errors due to surface tension effects. The proposed method eliminates these limitations, providing higher accuracy and temporal resolution. In addition, it enables the testing of larger samples and offers the potential for spatially resolved moisture analysis. The findings confirm that the method is suitable for studying moisture transport in porous materials and may serve as a valuable alternative to traditional gravimetric techniques. Full article

(This article belongs to the Section Construction and Building Materials)

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22 pages, 5507 KiB

Open AccessArticle

Experimental Study on the Pore Structure Evolution of Sandstone Under Brine Erosion

by Kang Peng, Tao Wu, Kun Luo, Song Luo, Jiaqi Zhou and Yuanmin Wang

Materials 2025, 18(15), 3500; https://doi.org/10.3390/ma18153500 - 25 Jul 2025

Abstract

The mechanical properties of sandstone, a common building material, are influenced by a variety of factors. In the coastal areas of China, groundwater has gradually become salinized into brine, which inevitably alters the original microstructure of rocks and affects the stability of underground [...] Read more.

The mechanical properties of sandstone, a common building material, are influenced by a variety of factors. In the coastal areas of China, groundwater has gradually become salinized into brine, which inevitably alters the original microstructure of rocks and affects the stability of underground structures. To clarify the evolution of the rock microstructure under brine erosion, this study used NMR technology to investigate the pore evolution characteristics of red sandstone under brine erosion. The experimental results show that the water absorption capacity of sandstone is influenced by the solution environment, with the lowest absorption rate occurring in regard to brine. The pores in red sandstone undergo significant changes after brine erosion. Factors such as the composition of the brine and soaking time affect sandstone porosity, with transformations of mini-pores and meso-pores leading to changes in porosity. In addition, XRD tests were carried out on the soaked red sandstone samples to analyze the changes in the main mineral components of the sandstone after brine erosion. Full article

(This article belongs to the Special Issue Cement-Based/Non-Cement-Based Constructional Materials: Multiscale Mechanics under Diverse Loadings)

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29 pages, 2021 KiB

Open AccessArticle

Research on the Macroscopic Mechanical Property Continuum of Square Lattices Composed of Piezoelectric Laminated Zigzag Beams

by Zengshuo Zhang and Jinxing Liu

Materials 2025, 18(15), 3499; https://doi.org/10.3390/ma18153499 - 25 Jul 2025

Abstract

A novel square lattice composed of piezoelectric laminated zigzag beams positioned between each pair of adjacent nodes is proposed. Each zigzag beam is made of four piezoelectric laminated straight beams, formed by laminating a piezoelectric layer and a base layer. The effective moduli [...] Read more.

A novel square lattice composed of piezoelectric laminated zigzag beams positioned between each pair of adjacent nodes is proposed. Each zigzag beam is made of four piezoelectric laminated straight beams, formed by laminating a piezoelectric layer and a base layer. The effective moduli are derived by analyzing the unit cell subjected to a stress field. Voltages applied to the piezoelectric layers can be adjusted to tailor the effective moduli of the lattice without altering the microstructure. Theoretical predictions were verified by finite element simulations. Parametric analyses were conducted to examine the effects of voltage on the tailoring of effective moduli in the piezoelectric laminated zigzag beam-based square lattices. Full article

(This article belongs to the Section Mechanics of Materials)

27 pages, 2990 KiB

Open AccessReview

Progress in the Circular Arc Source Structure and Magnetic Field Arc Control Technology for Arc Ion Plating

by Hao Du, Ke Zhang, Debin Liu and Wenchang Lang

Materials 2025, 18(15), 3498; https://doi.org/10.3390/ma18153498 - 25 Jul 2025

Abstract

Aiming at the goal of preparing high-quality coatings, this paper reviews the progress on circular arc source structure and magnetic field arc controlling technology in arc ion plating (AIP), with a focus on design characteristics of the different structures and configuration optimization of [...] Read more.

Aiming at the goal of preparing high-quality coatings, this paper reviews the progress on circular arc source structure and magnetic field arc controlling technology in arc ion plating (AIP), with a focus on design characteristics of the different structures and configuration optimization of the corresponding magnetic fields. The circular arc source, due to its simple structure, convenient installation, flexible target combination, high cooling efficiency, and high ionization rate and deposition rate, has shown significant application potential in AIP technology. In terms of magnetic field arc controlling technology, this paper delves into the design progress of various magnetic field configurations, including fixed magnetic fields generated by permanent magnets, dynamic rotating magnetic fields, axially symmetric magnetic fields, rotating transverse magnetic fields, and multi-mode alternating electromagnetic coupling fields. By designing the magnetic field distribution reasonably, the trajectory and velocity of the arc spot can be controlled precisely, thus reducing the generation of macroparticles, improving target utilization, and enhancing coating uniformity. In particular, the introduction of multi-mode magnetic field coupling technology has broken through the limitations of traditional single magnetic field structures, achieving comprehensive optimization of arc spot motion and plasma transport. Hopefully, these research advances provide an important theoretical basis and technical support for the application of AIP technology in the preparation for high-quality decorative and functional coatings. Full article

(This article belongs to the Section Materials Physics)

29 pages, 7153 KiB

Open AccessArticle

Study on the Damage Mechanisms in the Forming Process of High-Strength Steel Laser Tailor Welded Blanks Based on the Johnson–Cook Damage Model

by Xianping Sun, Huaqiang Li, Song Gao and Qihan Li

Materials 2025, 18(15), 3497; https://doi.org/10.3390/ma18153497 - 25 Jul 2025

Abstract

This paper, based on the Johnson–Cook damage model, investigates the damage mechanism of high-strength steel tailor welded blanks (TWBs) (Usibor1500P and Ductibor500) during the forming process. Initially, specimens with varying notch sizes were designed and fabricated to perform uniaxial tensile tests to determine [...] Read more.

This paper, based on the Johnson–Cook damage model, investigates the damage mechanism of high-strength steel tailor welded blanks (TWBs) (Usibor1500P and Ductibor500) during the forming process. Initially, specimens with varying notch sizes were designed and fabricated to perform uniaxial tensile tests to determine their mechanical properties. Then, the deformation process of the notched specimens was simulated using finite element software, revealing the distribution and variation of stress triaxiality at the fracture surface. By combining both experimental and simulation data, the parameters of the Johnson–Cook (J–C) damage model were calibrated, and the effects of temperature, strain rate, and stress triaxiality on material fracture behavior were further analyzed. Based on finite element analysis, the relevant coefficients for stress triaxiality, strain rate, and temperature were systematically calibrated, successfully establishing a J–C fracture criterion for TWB welds, Usibor1500P, and Ductibor500 high-strength steels. Finally, the calibrated damage model was further validated through the Nakajima-type bulge test, and the simulated Forming Limit Diagram (FLD) closely matched the experimental data. The results show that the analysis based on the J–C damage model can effectively predict the fracture behavior of tailor welded blanks (TWB) during the forming process. This study provides reliable numerical predictions for the damage behavior of high-strength steel laser-customized welded sheets and offers a theoretical basis for engineering design and material performance optimization. Full article

(This article belongs to the Section Manufacturing Processes and Systems)

20 pages, 7113 KiB

Open AccessArticle

Effect of Cu Content on Corrosion Resistance of 3.5%Ni Weathering Steel in Marine Atmosphere of South China Sea

by Yuanzheng Li, Ziyu Guo, Tianle Fu, Sha Sha, Bing Wang, Xiaoping Chen, Shujun Jia and Qingyou Liu

Materials 2025, 18(15), 3496; https://doi.org/10.3390/ma18153496 - 25 Jul 2025

Abstract

The influence of the copper (Cu) content on the corrosion resistance of 3.5%Ni low-carbon weathering steel was investigated using periodic dry–wet cycle accelerated corrosion tests. The mechanical properties of the steels were assessed via tensile and low-temperature impact tests, while corrosion resistance was [...] Read more.

The influence of the copper (Cu) content on the corrosion resistance of 3.5%Ni low-carbon weathering steel was investigated using periodic dry–wet cycle accelerated corrosion tests. The mechanical properties of the steels were assessed via tensile and low-temperature impact tests, while corrosion resistance was evaluated based on weight loss measurements. Surface oxide layers were characterized using three-dimensional laser confocal microscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and electrochemical methods. Electron probe microanalysis (EPMA) was employed to examine the cross-sectional morphology of the oxide layer after 72 h of accelerated corrosion tests. The results indicate that the solution state of Cu increased the strength of 3.5%Ni steels but significantly damaged the low-temperature toughness. As the Cu content increased from 0.75% to 1.25%, the corrosion rate decreased from 4.65 to 3.74 g/m² h. However, when there was a further increase in the Cu content to 2.15%, there was little decrease in the corrosion rate. With the increase in the Cu content from 0.75% to 2.15%, the surface roughness of 3.5%Ni weathering steel after corrosion decreased from 5.543 to 5.019 μm, and the corrosion behavior was more uniform. Additionally, the α/γ protective factor of the oxide layer of the surface layer increased from 2.58 to 2.84 with an increase in the Cu content from 0.75% to 1.25%, resulting in the oxide layer of the surface layer being more protective. For 1.25%Cu steel, the corrosion current density of rusted samples is lower (ranging from 1.2609 × 10⁻⁴ A/cm² to 3.7376 × 10⁻⁴ A/cm²), and the corrosion potential is higher (ranging from −0.85544 V to −0.40243 V). Therefore, the rusted samples are more corrosion resistant. The Cu in the oxide layer of the surface layer forms CuO and CuFeO₂, which are helpful for increasing corrosion resistance, which inhibits the penetration of Cl⁻. Full article

(This article belongs to the Special Issue Advances in Corrosion and Protection of Metallic Materials)

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