Materials

15 pages, 4179 KB

Open AccessArticle

Effect of Ta Content on the Microstructure and Properties of NiTiTa Functional Coatings In Situ Synthesized by Directed Energy Deposition

by Sansan Ao, Yawei Xing, Shaozhu Liu, Xinde Zuo and Yang Li

Materials 2025, 18(22), 5255; https://doi.org/10.3390/ma18225255 - 20 Nov 2025

Viewed by 370

Abstract

In this study, surface alloying technology based on Gas Tungsten Arc Welding (GTAW) was used to synthesize in situ NiTiTa coatings on a NiTi substrate using commercially pure Ta foils. The influence of different Ta contents (0.91, 1.42, and 2.91 at.%) on the [...] Read more.

In this study, surface alloying technology based on Gas Tungsten Arc Welding (GTAW) was used to synthesize in situ NiTiTa coatings on a NiTi substrate using commercially pure Ta foils. The influence of different Ta contents (0.91, 1.42, and 2.91 at.%) on the microstructure, phase formation, hardness, corrosion resistance, and X-ray visibility of the prepared coatings were systematically studied. These results show that the NiTiTa coatings fabricated by GTAW were free of microcracks with good surface quality and superior adhesion to the NiTi substrate. The NiTiTa coatings are mainly composed of columnar austenitic NiTi (B2), and martensitic NiTi (B19’) with (Ti, Ta)2Ni precipitating at the grain boundaries. The proportion of B19’ martensite and the Ta content dissolved in the NiTi matrix increases with the increasing addition of Ta. In addition, β-Ta appeared in the coating formed with 1.42 at.% Ta and precipitated abundantly when the Ta amount was increased to 2.91 at.%. Changes in phase composition and secondary phases lead to a decrease in the material nanohardness. To simulate the body fluid environment, corrosion tests were conducted in Hank’s solution at a rate of 0.5 mV/s. Electrochemical tests show that the NiTiTa coatings exhibit superior corrosion resistance, where the corrosion potential, Ecorr, increased with increasing Ta content. The enhanced X-ray visibility of the newly formed coatings was also revealed. This work provides a cost-effective method for in situ synthesis of NiTiTa coatings on NiTi alloys, highlighting its potential for improving the corrosion resistance and X-ray visibility of NiTi shape memory alloys. Full article

(This article belongs to the Special Issue Advanced Welding in Alloys and Composites, Second Edition)

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15 pages, 621 KB

Open AccessCommunication

Samarium-Doped Lead Phosphate Glass: Optical Experiments and Calculations Using the Judd–Ofelt Theory

by Joanna Pisarska and Wojciech A. Pisarski

Materials 2025, 18(22), 5254; https://doi.org/10.3390/ma18225254 - 20 Nov 2025

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Abstract

In this work, Sm³⁺-activated lead phosphate glass has been studied using spectroscopic methods. Based on absorption spectrum measurements, the oscillator strengths for Sm³⁺ ions were determined and compared to those calculated from the Judd–Ofelt theory. This procedure was applied to [...] Read more.

In this work, Sm³⁺-activated lead phosphate glass has been studied using spectroscopic methods. Based on absorption spectrum measurements, the oscillator strengths for Sm³⁺ ions were determined and compared to those calculated from the Judd–Ofelt theory. This procedure was applied to evaluate some radiative parameters (radiative transition rates, emission branching ratios, radiative lifetime) of Sm³⁺ ions in lead phosphate glass. Further luminescent studies indicate that lead phosphate glass doped with Sm³⁺ emits intense reddish-orange light due to ⁴G_5/2 ⟶ ⁶H_7/2 transition, for which several important spectroscopic parameters like emission linewidth and lifetime, quantum efficiency, peak stimulated emission cross-section, and figure of merit for laser gain were determined. The factors for Sm³⁺ ions in lead phosphate glass are as follows: η = 53%, FWHM = 10.5 nm, τ_exp = 1.925 ms, σ_em = 7.6 × 10⁻²² cm², σ_em × τ_exp = 14.6 × 10⁻²⁵ cm²s. The experimental and theoretical results suggest that samarium-doped lead phosphate glass can be successfully used as a reddish-orange-emitting component in photonic devices. Full article

(This article belongs to the Special Issue Research Progress in the Structure and Properties of Novel Functional Glasses)

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24 pages, 13685 KB

Open AccessArticle

Study of Preparation and Performance Porous Thermal Insulation Refractory Materials from Aluminum Ash and Red Mud

by Jiayi Zhong, Zichao Li, Weiyuan Li, Hongzhi Yue, Laijun Ma, Haoyu Zhao, Wenjuan Jiao, Yan Wang and Zhiyang Chang

Materials 2025, 18(22), 5253; https://doi.org/10.3390/ma18225253 - 20 Nov 2025

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Abstract

The risk of environmental accumulation of aluminum ash and red mud is increasing, emphasizing the demand for high-value utilization. In this study, the conversion of aluminum ash and red mud into porous refractory materials with good thermal insulation performance is successfully demonstrated, demonstrating [...] Read more.

The risk of environmental accumulation of aluminum ash and red mud is increasing, emphasizing the demand for high-value utilization. In this study, the conversion of aluminum ash and red mud into porous refractory materials with good thermal insulation performance is successfully demonstrated, demonstrating that both residues can be recovered as a resource and their environmental impact can be reduced in a sustainable manner. The phase composition and microstructure of the waste are evaluated by XRD and SEM/EDS, respectively, while their high-temperature behavior and performance were assessed through visual high-temperature furnace testing. The influence of the aluminum ash-red mud ratio on the rheological behavior of slurries containing surfactants at a constant alkaline pH was highlighted. A slurry composition of 40% red mud and 30% aluminum ash exhibited the lowest shear stress and viscosity values, required to facilitate bubble growth. Building on this formulation, foaming with 2% (mass fraction) H₂O₂ at 80 °C and sintering at 1250 °C produces a material with the optimum performance: a compressive strength of 1.03 MPa, a porosity of 58.55%, and thermal conductivity of 0.19 W/(m·K). The material exhibits long-lasting stability at temperatures ≤ 1100 °C. Thus, complementary compositions of aluminum ash and red mud show potential for practical application and value addition in the preparation of porous refractory materials with thermal insulation properties. Full article

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

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23 pages, 7062 KB

Open AccessArticle

Experimental and Molecular Dynamics Investigation of the Rejuvenation Effect of Bio-Oils on Aged High-Penetration Asphalt

by Hongxia Xiong, Shichao Liang, Quantao Liu, Shisong Ren, Georgios Pipintakos, Shaopeng Wu, Muyu Liu and Shi Xu

Materials 2025, 18(22), 5252; https://doi.org/10.3390/ma18225252 - 20 Nov 2025

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Abstract

The deterioration of high-penetration asphalt pavements due to oxidative aging presents a significant challenge in highway maintenance. This study investigates the rejuvenation effect of three bio-oils, namely palm oil, soybean oil, and sunflower oil, on aged PEN 90 asphalt through an integrated approach [...] Read more.

The deterioration of high-penetration asphalt pavements due to oxidative aging presents a significant challenge in highway maintenance. This study investigates the rejuvenation effect of three bio-oils, namely palm oil, soybean oil, and sunflower oil, on aged PEN 90 asphalt through an integrated approach combining experimental characterization and molecular dynamics (MD) simulations. Laboratory evaluations, including penetration, softening point, dynamic shear rheology (DSR), and Fourier Transform Infrared (FTIR) spectroscopy, were conducted to quantify the recovery of the physical, rheological, and chemical properties of aged high-penetration asphalt. MD simulations were conducted to provide insights into diffusion behavior and intermolecular interactions between bio-oil molecules and aged asphalt components. Experimental results show that bio-oils effectively restore the lost viscoelastic performance after long-term aging. An 8% dosage was determined as optimal, with rejuvenation efficiency decreasing in the order of SSO, SO, and PO. MD simulations clarify mechanisms by showing that soybean and palm oils have higher diffusion efficiency than sunflower oil, thus promoting the dispersion of asphaltene and resin. RDF shows that bio-oils enhance asphalt molecules’ short-range order via hydrogen bonds and van der Waals forces, which improves compatibility. Full article

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

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24 pages, 15566 KB

Open AccessArticle

Influence of Surface Roughness on the Mechanical Behavior of Granular Material Under Triaxial Shear: A DEM Study

by Yuqing Tang, Fengyin Liu, Meng Miao and Yu Yin

Materials 2025, 18(22), 5251; https://doi.org/10.3390/ma18225251 - 20 Nov 2025

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Abstract

This study investigates the mechanical behavior of glass bead specimens with different surface roughness under triaxial testing using the Discrete Element Method (DEM). The microscopic parameters for the DEM simulation were calibrated by referencing macroscopic triaxial test data, specifically stress–strain relationships and volumetric [...] Read more.

This study investigates the mechanical behavior of glass bead specimens with different surface roughness under triaxial testing using the Discrete Element Method (DEM). The microscopic parameters for the DEM simulation were calibrated by referencing macroscopic triaxial test data, specifically stress–strain relationships and volumetric changes. We examined the evolution of the contact force network by analyzing the contact forces and the coordination numbers. Our findings indicate that a higher coefficient of interparticle friction results in stronger contact forces, but with a reduced coordination number. A detailed analysis reveals that the strong force network with higher friction, characterized by higher contact forces and a greater density of contacts, becomes more predominant in specimens. Quantitative measures of anisotropy further show that the contact orientations, normal forces, and tangential forces become increasingly anisotropic during shear. These micromechanical findings directly link the enhancement of macroscopic shear strength to the underlying evolution of anisotropic force chains, offering microscopic evidence into the behavior of rough granular materials. Full article

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2 pages, 137 KB

Open AccessEditorial

Advanced Multifunctional Coatings for New Applications: A New, Open Special Issue of Materials

by Tao Wang and Stephan Handschuh-Wang

Materials 2025, 18(22), 5250; https://doi.org/10.3390/ma18225250 - 20 Nov 2025

Viewed by 277

Abstract

From information technology, life, and healthcare to the energy revolution and sustainable development, a series of major technological breakthroughs depend on the substantial improvement of material properties [...] Full article

(This article belongs to the Special Issue Advanced Multifunctional Coatings for New Applications)

20 pages, 12144 KB

Open AccessReview

Research Progress on LDH Corrosion-Resistant Films on Magnesium Alloy: A Review

by Huan Li, Xue Bai and Wenjin Chen

Materials 2025, 18(22), 5249; https://doi.org/10.3390/ma18225249 - 20 Nov 2025

Viewed by 613

Abstract

As the lightest structural materials among practical metals, magnesium (Mg) alloys have broad application prospects in various fields, including automobiles, electronics, communications, aerospace and biomaterials. However, the main problem currently limiting their industrial application is poor corrosion resistance. Therefore, improving the corrosion resistance [...] Read more.

As the lightest structural materials among practical metals, magnesium (Mg) alloys have broad application prospects in various fields, including automobiles, electronics, communications, aerospace and biomaterials. However, the main problem currently limiting their industrial application is poor corrosion resistance. Therefore, improving the corrosion resistance of Mg alloys has important practical value and significance. As a type of two-dimensional nanomaterial, layered double hydroxide (LDH) can serve as a micro/nanocarrier for corrosion inhibitors. Through applying LDH to constructing an in situ intelligent protective film on the surface of Mg alloy, the poor corrosion resistance of Mg alloy surfaces can be effectively improved. This paper aims to introduce the structure and properties of LDH films and provide a detailed analysis of the preparation methods and characteristics of LDH films on Mg alloy. Based on summarizing the research progress in the functional modification of LDH films for self-healing, superhydrophobic, slippery liquid-infused porous surfaces (SLIPSs) and wear-resistant coatings, the future development directions and existing challenges are discussed. Full article

(This article belongs to the Section Metals and Alloys)

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19 pages, 9088 KB

Open AccessArticle

Application of Response Surface Methodology for Modeling and Optimization of the Top Surface Ironing Process in Parts Produced by MEX 3D Printing

by Andrzej Matras

Materials 2025, 18(22), 5248; https://doi.org/10.3390/ma18225248 - 20 Nov 2025

Viewed by 404

Abstract

This study analyzes the influence of material extrusion (MEX) 3D printing and ironing parameters on parts made of polylactic acid (PLA), such as top surface roughness and flatness. Surface ironing is one of the post-processing methods. It is an interesting alternative to the [...] Read more.

This study analyzes the influence of material extrusion (MEX) 3D printing and ironing parameters on parts made of polylactic acid (PLA), such as top surface roughness and flatness. Surface ironing is one of the post-processing methods. It is an interesting alternative to the most commonly used mechanical or chemical treatments. It does not require the use of any additional devices or substances; however, it can only be used on flat surfaces, requires additional time for application, and a flush may form at the edges of the ironed surface. The Response Surface Methodology (RSM) was used for modeling the analyzed processes. The presented methodology assumes a two-stage approach. First, the printing process of the top surface is optimized. Then, the ironing of the top surface is optimized. Improvement of surface roughness and flatness was adopted as the optimization criterion. The influence of extruder temperature, printing speed, and filament flow used during printing of the top surface, as well as extruder temperature, ironing speed, and distance between passes used during ironing, was examined. The significance of the influence of the analyzed parameters was determined using ANOVA and Pareto diagrams. The use of the applied research methodology and created mathematical models allows for determining the relationship between the optimal extruder temperature, extrusion flow, speed, and distance between passes during ironing while ensuring high process efficiency. The ironing resulted in a fivefold reduction in the Ra and an eightfold reduction in the FLTq parameters. A surface with Ra = 1.09 μm and FLTq = 3.4 μm was obtained. Full article

(This article belongs to the Special Issue Advances in Computer Numerical Control Machining and Precision Machining of Advanced Materials)

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22 pages, 2267 KB

Open AccessArticle

Quantitative Depth Estimation in Lock-In Thermography: Modeling and Correction of Lateral Heat Conduction Effects

by Botao Ma, Shupeng Sun and Lin Zhang

Materials 2025, 18(22), 5247; https://doi.org/10.3390/ma18225247 - 20 Nov 2025

Viewed by 433

Abstract

Lock-in thermography is a widely used nondestructive testing technique for detecting subsurface defects in solid materials. In this study, one-dimensional analytical modeling and three-dimensional finite element simulations were combined to elucidate how lateral heat conduction influences quantitative depth estimation in titanium alloy material [...] Read more.

Lock-in thermography is a widely used nondestructive testing technique for detecting subsurface defects in solid materials. In this study, one-dimensional analytical modeling and three-dimensional finite element simulations were combined to elucidate how lateral heat conduction influences quantitative depth estimation in titanium alloy material using two inversion strategies: the blind frequency method and the phase difference method. Parametric analyses were conducted for defect radius-to-depth ratios ranging from 0.5 to 8 under various excitation frequencies. Results show that the blind frequency method can significantly underestimate defect depth with errors of up to 20.7% when the radius-to-depth ratio is as small as 0.5. To mitigate this bias, an exponential correction model was developed to compensate for lateral conduction effects, reducing the error to within ±5%. The accuracy of the phase difference method is found to depend jointly on defect depth, excitation frequency, and the ratio of defect radius to thermal diffusion length; estimation errors become negligible when this ratio exceeds 3. The novelty of this work lies in identifying lateral conduction as a key bias source and establishing a quantitative correction framework for the depth inversion based on the blind frequency method. The proposed approach is expected to enhance the accuracy of quantitative thermography for engineering applications. Full article

(This article belongs to the Special Issue Multiscale Simulation and Properties of Advanced Materials: Microstructure Evolution and Mechanical Analysis)

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25 pages, 5741 KB

Open AccessArticle

Stabilizing the Localized Surface Plasmon Resonance (LSPR) of Citrate-Synthesized Metal Nanoparticles in Organic Solvents

by Jacob P. Magdon, Matthew J. Jasienski, Madison R. Waltz, Gabrielle A. Grzymski, Calvin Chen, Arion M. Solomon, Minh Dang Nguyen, Jong Moon Lee, John C. Deàk, T. Randall Lee and Riddhiman Medhi

Materials 2025, 18(22), 5246; https://doi.org/10.3390/ma18225246 - 20 Nov 2025

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Abstract

Gold–silver nanoshells (GS-NSs) are hollow spherical nanoparticles with an alloyed Ag-Au shell. GS-NSs exhibit a tunable localized surface plasmon resonance (LSPR) in the visible to near-IR wavelengths as a function of composition and shell thickness and offer greater stability across pH ranges compared [...] Read more.

Gold–silver nanoshells (GS-NSs) are hollow spherical nanoparticles with an alloyed Ag-Au shell. GS-NSs exhibit a tunable localized surface plasmon resonance (LSPR) in the visible to near-IR wavelengths as a function of composition and shell thickness and offer greater stability across pH ranges compared to other metal nanoparticles. These properties make GS-NSs promising materials for diagnostics, photothermal therapy, and photocatalysis. However, current research has explored GS-NSs only in aqueous systems, since they immediately aggregate in other solvents, limiting their utility. This paper provides an in-depth study of the choice and effect of non-thiol ligands on the stability and phase-transfer of GS-NSs from aqueous to non-aqueous solvents, such as ethylene glycol, tetrahydrofuran, dichloromethane, and toluene. Ligand exchange for functionalization of GS-NSs was performed with Triton X-100 (TX100), sodium stearate (NaSt), polyvinylpyrrolidone (PVP), and hydroxypropyl cellulose (HPC), prior to phase-transfer. The nanoparticles were phase-transferred to the non-aqueous solvents, and the stability of the colloids in the various solvents before and after functionalization was recorded with UV–visible spectroscopy, dynamic light scattering (DLS), zeta potential (ζ), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The study was also extended to include silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) to evaluate broad-range applicability. Among the ligands studied, HPC functionalization demonstrated the widest range of phase-transfer stability across 21 days for all three particle systems studied. UV–vis spectroscopy demonstrated sustained LSPR integrity after HPC functionalization in EG, THF, and DCM. SEM, TEM, and hydrodynamic size measurements by DLS further confirmed no aggregation in EG, THF, and DCM but suggested possible twinning or clustering in the solution. Overall, this work successfully identified non-toxic alternatives to expand the LSPR stability of citrate-synthesized metal nanoparticles in organic solvents. Full article

(This article belongs to the Special Issue Nanowires and Nanoparticles: Synthesis, Characterization and Applications)

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20 pages, 4047 KB

Open AccessArticle

Research on Mixing Uniformity Evaluation and Molding Method for Crumb Rubber Asphalt Mixtures

by Wenhua Wang, Yi Lu, Lingdi Kong, Wenke Yan, Yilong Li, Mulian Zheng, Chuan Lu and Guanglei Qu

Materials 2025, 18(22), 5245; https://doi.org/10.3390/ma18225245 - 20 Nov 2025

Viewed by 357

Abstract

The broader adoption of crumb rubber asphalt mixtures (CRAM) as sustainable pavement materials is currently limited by two key technical barriers. Firstly, there is a lack of standardized methods to evaluate mixing uniformity. Secondly, the material’s tendency for elastic recovery after compaction remains [...] Read more.

The broader adoption of crumb rubber asphalt mixtures (CRAM) as sustainable pavement materials is currently limited by two key technical barriers. Firstly, there is a lack of standardized methods to evaluate mixing uniformity. Secondly, the material’s tendency for elastic recovery after compaction remains problematic. These barriers ultimately hinder the realization of CRAM’s full potential in vibration reduction, noise abatement, and resource recycling. To improve the performance evaluation system of CRAM and promote its development in engineering applications. Based on the distribution characteristics of crumb rubber in asphalt mixtures, this study established a crumb rubber distribution area moment model. It proposed a coefficient of area–distance variation to evaluate the mixing uniformity of CRAM. Through compaction tests and orthogonal tests, the effects of mixing process, mixing time, mixing temperature, compaction temperature, compaction times, and compaction method on the mixing uniformity and performance of CRAM are systematically investigated. The results show that, compared with specimens prepared by single compaction and compaction after high-temperature curing, CRAM specimens prepared by secondary compaction exhibit superior mechanical performance. The 24 h elastic recovery rate of these specimens is reduced to 24% of that in single-compacted specimens. The mixing process and mixing time have a significant impact on the mixing uniformity of CRAM. Pre-mixing crumb rubber with aggregates or extending the mixing time can improve the CRAM mixing uniformity by 45% and 18%, respectively. The mixing and compaction temperatures primarily affect the bulk density and Marshall stability of the specimens. When the mixing and compaction temperatures are 180 °C and 170 °C, respectively, the bulk density and Marshall stability of the molded specimens reach their maximum values. Through orthogonal analysis, the optimal mixing method for CRAM is determined as follows: mix aggregates and crumb rubber at 180 °C for 40 s, then add asphalt and continue mixing for another 80 s. The optimal process for secondary compaction is as follows: the first compaction at 170 °C, compacting each side 47 times, and the second compaction at 80 °C, compacting each side 23 times. 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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17 pages, 6200 KB

Open AccessArticle

Effect of Solution Temperature on the Microstructure and Properties of AlSi37Cu0.7Mg0.9Ni0.2 Alloy Prepared by Rapid Solidification and Hot Extrusion

by Xiaodong Mao, Zhenning Chen, Ningjie Gu, Dongnan Huang and Linzhong Zhuang

Materials 2025, 18(22), 5244; https://doi.org/10.3390/ma18225244 - 20 Nov 2025

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Abstract

This study systematically investigated the effects of solution temperature (460–560 °C) on the microstructure, mechanical properties, and corrosion behavior of AlSi37Cu0.7Mg0.9Ni0.2 alloy rods prepared by rapid solidification and hot-extrusion. The results demonstrated that the solution temperature critically governed the alloy’s recrystallization behavior, precipitation [...] Read more.

This study systematically investigated the effects of solution temperature (460–560 °C) on the microstructure, mechanical properties, and corrosion behavior of AlSi37Cu0.7Mg0.9Ni0.2 alloy rods prepared by rapid solidification and hot-extrusion. The results demonstrated that the solution temperature critically governed the alloy’s recrystallization behavior, precipitation kinetics, and phase distribution. With the increase in solution temperature, the alloy exhibited progressive grain coarsening (from 4.51 μm at 460 °C to 13.25 μm at 560 °C) and enhanced precipitation hardening, leading to a 108.8% increase in hardness (198.4 HV at 560 °C) but a concurrent reduction in ductility (from 2.5% to 1.0%). Electrical conductivity initially improved by 3.4% at 460 °C (27.44% IACS) compared with the extruded state, but deteriorated at higher temperatures due to increased electron scattering. Anodic oxidation tests revealed a non-monotonic corrosion trend, with maximum weight loss (57.50 mg·g⁻¹) occurring at 480 °C due to microstructural inhomogeneity, while higher temperatures (560 °C) partially restored corrosion resistance. Electrochemical analysis corroborated these findings, showing the 480-treated sample exhibited the lowest corrosion potential (−1.0159 V). Microstructural characterization confirmed that optimal mechanical properties were achieved through a combination of fine β″-Mg₂Si (<20 nm), θ′-Al₂Cu precipitates, and thermally stable Al₃Ni phase. These results established a comprehensive process-structure-property relationship, which provided critical guidance for tailoring the alloy’s performance in structural–functional applications. Full article

(This article belongs to the Section Metals and Alloys)

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18 pages, 4565 KB

Open AccessArticle

Effect of Temperature on Corrosion of HSLA Steels with Different Cr Contents in a Water-Saturated Supercritical CO₂ Environment

by Qilin Ma, Shilin Liu, Yi Ren, Leng Peng, Ba Li, Chengjia Shang and Shujun Jia

Materials 2025, 18(22), 5243; https://doi.org/10.3390/ma18225243 - 20 Nov 2025

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Abstract

This study investigates the effects of chromium (0.4~1.2) Cr content and temperature (35–80 °C) on the corrosion behavior and mechanisms of steels in a water-saturated supercritical CO₂ (S-CO₂) environment, aiming to provide theoretical foundations for material selection and corrosion management [...] Read more.

This study investigates the effects of chromium (0.4~1.2) Cr content and temperature (35–80 °C) on the corrosion behavior and mechanisms of steels in a water-saturated supercritical CO₂ (S-CO₂) environment, aiming to provide theoretical foundations for material selection and corrosion management in S-CO₂ pipeline systems. Results indicate that increasing Cr content promotes the formation of granular bainite as the dominant microstructure, accompanied by refined martensite–austenite (MA) constituents with increased population and reduced dimensions, leading to enhanced strength at the expense of toughness. In the S-CO₂/H₂O environment, Cr reacts with CO₂ to form a dense Cr₂O₃ layer, significantly suppressing the corrosion rate. Temperature critically governs corrosion kinetics: at 35 °C, where S-CO₂ exhibits maximum density and CO₂ solubility in water peaks, electrochemical corrosion dominates, resulting in the highest corrosion rate. As temperature rises, the corrosion mechanism transitions to chemical corrosion, while accelerated formation of protective corrosion product films further reduces corrosion rates. Mechanistic analysis reveals that uniform corrosion arises from carbonic acid generated by water dissolution in S-CO₂, whereas localized corrosion intensifies upon direct contact between precipitated aqueous phases and the steel surface. These findings offer critical theoretical foundations for optimizing material design, operational parameters, and corrosion mitigation strategies in S-CO₂ transportation infrastructure. Full article

(This article belongs to the Special Issue Corrosion Behavior and Mechanical Properties of Metallic Materials (Second Edition))

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25 pages, 7269 KB

Open AccessArticle

Development of an Ergonomic Additively Manufactured Modular Saddle for Rehabilitation Cycling

by Alberto Iglesias Calcedo, Chiara Bregoli, Valentina Abbate, Marta Mondellini, Jacopo Fiocchi, Gennaro Rollo, Cristina De Capitani, Marino Lavorgna, Marco Sacco, Andrea Sorrentino, Ausonio Tuissi, Carlo Alberto Biffi and Alfredo Ronca

Materials 2025, 18(22), 5242; https://doi.org/10.3390/ma18225242 - 19 Nov 2025

Viewed by 354

Abstract

This work reports the design, fabrication, and validation of a modular ergonomic saddle for rehabilitation cycling, developed through a combined additive manufacturing approach. The saddle consists of a metallic support produced by Laser Powder Bed Fusion (LPBF) in AISI 316L stainless steel and [...] Read more.

This work reports the design, fabrication, and validation of a modular ergonomic saddle for rehabilitation cycling, developed through a combined additive manufacturing approach. The saddle consists of a metallic support produced by Laser Powder Bed Fusion (LPBF) in AISI 316L stainless steel and a polymeric ergonomic covering fabricated via Selective Laser Sintering (SLS) using thermoplastic polyurethane (TPU). A preliminary material screening between TPU and polypropylene (PP) was conducted, with TPU selected for its superior elastic response, energy dissipation, and more favourable SLS processability, as confirmed by thermal analyses. A series of gyroid lattice configurations with varying cell sizes and wall thicknesses were designed and mechanically tested. Cyclic testing under both stress- and displacement-controlled conditions demonstrated that the configuration with 8 mm cell size and 0.3 mm wall thickness provided the best balance between compliance and stability, showing minimal permanent deformation after 10,000 cycles and stable force response under repeated displacements. Finite Element Method (FEM) simulations, parameterized using experimentally derived elastic and density data, correlated well with the mechanical results, correlated with the mechanical results, supporting comparative stiffness evaluation. Moreover, a cost model focused on the customizable TPU component confirmed the economic viability of the modular approach, where the metallic base remains a reusable standard. Finally, the modular saddle was fabricated and successfully mounted on a cycle ergometer, demonstrating functional feasibility. Full article

(This article belongs to the Special Issue Additive Manufacturing and Forming Technologies of Alloy: Mechanical Properties and Microstructure Evaluation)

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15 pages, 1941 KB

Open AccessArticle

Influence of Fused Filament Fabrication Strategy on Polyamide Properties

by Marta Beata Krawczyk, Marcin Andrzej Królikowski and Kamil Urbanowicz

Materials 2025, 18(22), 5241; https://doi.org/10.3390/ma18225241 - 19 Nov 2025

Viewed by 434

Abstract

This study investigates the influence of Fused Filament Fabrication (FFF) parameters on the properties of polyamide (PA, Nylon™) parts, which are valued for their excellent mechanical properties in additive manufacturing. The parameters examined include infill structure (diagonal and honeycomb), infill density (60%, 80%, [...] Read more.

This study investigates the influence of Fused Filament Fabrication (FFF) parameters on the properties of polyamide (PA, Nylon™) parts, which are valued for their excellent mechanical properties in additive manufacturing. The parameters examined include infill structure (diagonal and honeycomb), infill density (60%, 80%, and 100%), and sample orientation (0°, 45°, and 90°) relative to the build plate. Filaments from five manufacturers were tested, with injection-molded samples serving as references. Standard tensile strength tests were performed. The results indicate that the 0° orientation yielded the highest tensile strength, while the 45° and 90° orientations exhibited distinct behaviors associated with the geometry of additive manufacturing. The highest Young’s modulus was obtained for solid infill at 0° orientation. Although infill structure had a smaller effect, the honeycomb pattern provided more stable and superior mechanical properties at higher infill densities. The study compared filaments from different manufacturers, identifying two that met the tensile strength requirements for telerehabilitation device case prototypes. Full article

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

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24 pages, 6607 KB

Open AccessArticle

Synergistic Gypsum–Carbonation Strategy and Non-Contact ITZ Quantification for CFBFA Artificial Aggregate Concrete

by Nuo Xu, Mingyi Guo, Yiheng Chen, Rentuoya Sa, Mao Huo and Suxia Ma

Materials 2025, 18(22), 5240; https://doi.org/10.3390/ma18225240 - 19 Nov 2025

Viewed by 436

Abstract

This study explores an integrated strategy combining gypsum activation and pressurized flue gas heat curing (FHC) to enhance the interfacial transition zone (ITZ) in concrete incorporating over 80% circulating fluidized bed fly ash (CFBFA)-based artificial coarse aggregates. The inherently weak ITZ, characterized by [...] Read more.

This study explores an integrated strategy combining gypsum activation and pressurized flue gas heat curing (FHC) to enhance the interfacial transition zone (ITZ) in concrete incorporating over 80% circulating fluidized bed fly ash (CFBFA)-based artificial coarse aggregates. The inherently weak ITZ, characterized by low bonding strength and high porosity, remains a major limitation to the mechanical performance of CFBFA-based concrete. Gypsum promotes the formation of ettringite (AFt) and facilitates the development of a dense CaCO₃ shell through enhanced carbonation. Their synergistic effect improves microstructural homogeneity and reduces crack connectivity at the interface. A novel grayscale image-based double-peak gradient method is developed for non-contact, quantitative measurement of ITZ thickness, revealing a strong inverse correlation (R² = 0.87) between ITZ thickness and compressive strength. Microstructural analyses confirm that the dual treatment significantly refines the ITZ, resulting in denser aggregate interiors, improved matrix continuity, and more structurally integrated interfaces. The failure mode correspondingly shifts from interface-dominated fracture to composite-controlled behavior. These findings demonstrate the effectiveness of the FHC–gypsum approach in tailoring ITZ morphology and enhancing mechanical integrity, offering a viable pathway for high-performance, low-carbon cementitious composites utilizing industrial by-products. Full article

(This article belongs to the Section Mechanics of Materials)

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14 pages, 5203 KB

Open AccessArticle

Synthesis, Structure and Dielectric Characteristics of Tellurovanadate Glasses Containing Bismuth Oxide

by Tina Tasheva and Stanislav Slavov

Materials 2025, 18(22), 5239; https://doi.org/10.3390/ma18225239 - 19 Nov 2025

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Abstract

Two series of glasses with compositions (90 − x)TeO₂-xV₂O₅-10Bi₂O₃ and (80 − x)TeO₂-xV₂O₅-20Bi₂O₃, where x = 20, 30, 40 mol %, were synthesized. Glasses [...] Read more.

Two series of glasses with compositions (90 − x)TeO₂-xV₂O₅-10Bi₂O₃ and (80 − x)TeO₂-xV₂O₅-20Bi₂O₃, where x = 20, 30, 40 mol %, were synthesized. Glasses were obtained by the melt-quenching technique. The molar volume (33.48–48.37 cm³/mol) and oxygen packing density (71.69–77.64 mol/cm³) were calculated based on experimental density measurements. Both parameters increase with the increase in V₂O₅ and the decrease in TeO₂ content. Infrared spectra were recorded in the range of 2000–400 cm⁻¹ and Raman spectra in the 90–1280 cm⁻¹ range. The C1s, O1s, Te3d, V2p and Bi4f photoelectron lines were recorded. The dielectric characteristics of the glasses were measured by impedance spectroscopy at room temperature in the frequency range from 100 Hz to 1 MHz. The glasses in the studied system demonstrate a strong dependence on the composition, with the occasional addition of high contents of TeO₂ and V₂O₅ leading to a significant change in the dielectric properties of the samples. Full article

(This article belongs to the Section Electronic Materials)

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25 pages, 2871 KB

Open AccessArticle

Numerical and Experimental Correlation Between Half-Cell Potential and Steel Mass Loss in Corroded Reinforced Concrete

by Max Lawrence L. Li, Seong-Hoon Kee, Cris Edward F. Monjardin and Kevin Paolo V. Robles

Materials 2025, 18(22), 5238; https://doi.org/10.3390/ma18225238 - 19 Nov 2025

Viewed by 491

Abstract

Half-cell potential (HCP) measurement is widely applied as a non-destructive technique for assessing corrosion probability, yet its diagnostic capacity remains limited to probabilistic interpretations rather than quantifying the extent of steel mass loss. Conventional HCP measurements can indicate corrosion probability, but not the [...] Read more.

Half-cell potential (HCP) measurement is widely applied as a non-destructive technique for assessing corrosion probability, yet its diagnostic capacity remains limited to probabilistic interpretations rather than quantifying the extent of steel mass loss. Conventional HCP measurements can indicate corrosion probability, but not the actual extent of deterioration. The objective of this study is to examine the potential of HCP measurements to indicate actual corrosion severity by numerically simulating HCP values and correlating them with steel mass loss data. Using published experimental datasets, relationships among corrosion current density (J₍corr₎), electrical resistivity (ER), HCP, and steel mass loss (m_L) were established through regression analysis, while COMSOL Multiphysics v6.2 was employed to simulate HCP responses. The simulations revealed increasingly negative HCP values with higher J₍corr₎ and conductivity. A second-order polynomial correlation (R² = 0.9999) was obtained between simulated HCP and measured mass loss (0–20%), enabling quantitative interpretation of corrosion severity, demonstrating that HCP can serve as a predictive indicator of corrosion severity. It is demonstrated that the interpretative value of HCP has potential for quantifying corrosion severity to improve monitoring and maintenance strategies. Full article

(This article belongs to the Special Issue Advanced Cement and Concrete Composite Materials)

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39 pages, 2270 KB

Open AccessReview

Laser Technologies of Welding, Surfacing and Regeneration of Metals with HCP Structure (Mg, Ti, Zr): State of the Art, Challenges and Prospects

by Adam Zwoliński, Sylwester Samborski and Jakub Rzeczkowski

Materials 2025, 18(22), 5237; https://doi.org/10.3390/ma18225237 - 19 Nov 2025

Viewed by 556

Abstract

Metals with a hexagonal close-packed (HCP) structure such as magnesium, titanium and zirconium constitute key structural materials in the aerospace, automotive, biomedical and nuclear energy industries. Their welding and regeneration by conventional methods is hindered due to the limited number of slip systems, [...] Read more.

Metals with a hexagonal close-packed (HCP) structure such as magnesium, titanium and zirconium constitute key structural materials in the aerospace, automotive, biomedical and nuclear energy industries. Their welding and regeneration by conventional methods is hindered due to the limited number of slip systems, high reactivity and susceptibility to the formation of defects. Laser technologies offer precise energy control, minimization of the heat-affected zone and the possibility of producing joints and coatings of high quality. This article constitutes a comprehensive review of the state of knowledge concerning laser welding, cladding and regeneration of HCP metals. The physical mechanisms of laser beam interactions are discussed including the dynamics of the keyhole channel, Marangoni flows and the formation of gas defects. The characteristics of the microstructure of joints are presented including the formation of α′ martensite in titanium, phase segregation in magnesium and hydride formation in zirconium. Particular attention is devoted to residual stresses, techniques of cladding protective coatings for nuclear energy with Accident Tolerant Fuel (ATF) and advanced numerical modeling using artificial intelligence. The perspectives for the development of technology are indicated including the concept of the digital twin and intelligent real-time process control systems. Full article

(This article belongs to the Special Issue Microstructural and Mechanical Properties of Metal Alloys)

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14 pages, 1639 KB

Open AccessReview

Review of Radiation Embrittlement of Aluminum Alloys Used in Research Reactors

by Ferenc Gillemot, Murthy Kolluri, Ildiko Szenthe, Frideriki Naziris and Lajos Berzy

Materials 2025, 18(22), 5236; https://doi.org/10.3390/ma18225236 - 19 Nov 2025

Viewed by 428

Abstract

Research reactors are generally built from aluminum alloys during the last century. Most of the operation times of them already exceed the design lifetime. The original mechanical properties change during service. The radiation embrittlement affects them through three mechanisms: the transmutation of aluminum [...] Read more.

Research reactors are generally built from aluminum alloys during the last century. Most of the operation times of them already exceed the design lifetime. The original mechanical properties change during service. The radiation embrittlement affects them through three mechanisms: the transmutation of aluminum to silicon caused by thermal neutrons, gases (hydrogen, helium) occur by fast neutron transmutation, causing swelling, and matrix defects (dislocations, voids) occur by fast neutron irradiation. This paper summarizes the existing knowledge of the radiation degradation of aluminum alloys. Full article

(This article belongs to the Special Issue Advances in Irradiation Effects of Materials for Current and Future Reactors)

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13 pages, 2838 KB

Open AccessArticle

Laser-Based Crystallization of Chemical Solution Deposited Proton-Conducting Thin Films

by Jonas Frühling, Samuel Fink, Theodor Schneller and Christian Vedder

Materials 2025, 18(22), 5235; https://doi.org/10.3390/ma18225235 - 19 Nov 2025

Viewed by 364

Abstract

This work investigates the laser-based solid-phase crystallization of wet-chemically deposited BZY (yttrium doped barium zirconate) thin films on metallic substrates. For this purpose, amorphous BZY thin films are deposited on nickel-based alloy substrates using spin coating and are then annealed using laser radiation. [...] Read more.

This work investigates the laser-based solid-phase crystallization of wet-chemically deposited BZY (yttrium doped barium zirconate) thin films on metallic substrates. For this purpose, amorphous BZY thin films are deposited on nickel-based alloy substrates using spin coating and are then annealed using laser radiation. Different laser intensities and scanning velocities are investigated. X-ray diffraction analysis of the processed thin films shows an initial increase in crystallinity with increasing laser intensity. A further increase in laser intensity leads to the formation of secondary phases and ultimately to the melting of the substrate material. Complete crystallization of the thin films without the formation of secondary phases is achieved by applying scanning velocities of

v_{S}

≥ 500 mm/s. Scanning electron microscopy images of selected samples show that, especially at higher scanning velocities, crack formation can occur as a result of the annealing. In summary, laser annealing is a promising approach for the thermal post-treatment of BZY thin films in applications in metal-supported solid oxide fuel cells. Full article

(This article belongs to the Special Issue Advances in Laser Processing Technology of Materials—Second Edition)

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16 pages, 5496 KB

Open AccessArticle

Dynamic Compressive Mechanical Behavior of a Novel Three-Dimensional Re-Entrant Honeycomb (3D-RH) Structure

by Xiyan Du, Lun Qi, Yulong Shi, Lei Xing, Gang Wang, Haibo Zhang, Wenting Bai, Xiaofei Cao and Chunwang He

Materials 2025, 18(22), 5234; https://doi.org/10.3390/ma18225234 - 19 Nov 2025

Viewed by 311

Abstract

Negative Poisson’s ratio structural materials have unique deformation characteristics and excellent mechanical properties, and are widely used in multiple key fields, such as aerospace, nuclear safety, rail transit, and so on. However, most of them are two-dimensional negative Poisson’s ratio structural materials, and [...] Read more.

Negative Poisson’s ratio structural materials have unique deformation characteristics and excellent mechanical properties, and are widely used in multiple key fields, such as aerospace, nuclear safety, rail transit, and so on. However, most of them are two-dimensional negative Poisson’s ratio structural materials, and the mechanical design and performance evaluation of dynamic behavior of three-dimensional novel negative Poisson’s ratio structural materials deserve more attention. Inspired by the deformation mechanism of the traditional two-dimensional re-entrant honeycomb (2D-RH) structure, this study extends the planar structural characteristics to the spatial dimension and proposes a novel three-dimensional re-entrant honeycomb (3D-RH) structure. Experimental testing, theoretical analysis, and numerical simulation are all utilized to study its quasi-static and dynamic compressive mechanical properties and deformation processes. The novelty of this paper lies in the novel 3D-RH structure and the investigation of the static and dynamic mechanical behavior. The testing results indicate that the quasi-static compressive performance curve of the 3D-RH pattern is a typical bending-dominated deformation behavior, and the dynamic mechanical properties of the 3D-RH structural pattern exhibit an apparent strain rate effect. In addition, Ashby maps are also plotted to demonstrate its acceptable performance characteristics, indicating its potential attractive application prospects in innovative development of lightweight, high-specific-stiffness, and high-specific-strength structural materials. Full article

(This article belongs to the Special Issue Modeling and Simulations of the Dynamic Mechanical Performance of Materials and Structures)

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25 pages, 5434 KB

Open AccessArticle

Application of an Improved Dual-Branch Model Based on Multi-Scale Feature Fusion in Fracture Surface Image Recognition

by Fei Gao, Denghui Wang, Fulai Yang, Mingping Zhou, Yuan Li, Zhen Zheng, Jianpeng Shi and Zheng Zhang

Materials 2025, 18(22), 5233; https://doi.org/10.3390/ma18225233 - 19 Nov 2025

Viewed by 424

Abstract

In order to improve the recognition accuracy and model interpretability of metal fracture scanning electron microscope (SEM) images, this research presents an improved dual-branch model (IDBM) based on multi-scale feature fusion. This model employs VGG19 and Inception V3 as parallel branches to separately [...] Read more.

In order to improve the recognition accuracy and model interpretability of metal fracture scanning electron microscope (SEM) images, this research presents an improved dual-branch model (IDBM) based on multi-scale feature fusion. This model employs VGG19 and Inception V3 as parallel branches to separately extract local texture features and global semantic features. Furthermore, it integrates channel and spatial attention mechanisms to enhance the responsiveness of discriminative regions. By integrating dual-branch features using a fixed fusion ratio of 0.8:0.2, the model was trained and validated on an image dataset comprising 800 representative fracture surface images across four categories: cleavage, dimple, fatigue, and intergranular fracture. The results indicate that under small-sample data conditions, the IDBM achieves a Validation Accuracy (Val ACC) of 99.50%, a Recall rate of 99.51%, and an Area Under The Curve (AUC) value of 0.9998, significantly outperforming single models and other fusion strategies. Through integration with class activation mapping (CAM) and feature space visualization analysis, the model exhibits strong interpretability. Furthermore, scale adaptability tests reveal that IDBM maintains stable recognition performance across a magnification range of 100 to 10,000 times, and identifies the optimal observation magnification ranges for the four types of fractures. Full article

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

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18 pages, 9834 KB

Open AccessArticle

Numerical Analysis of Cross-Laminated Timber Panels Under Three-Point Bending Using Laminate Theory

by Michal Bošanský and Miroslav Trcala

Materials 2025, 18(22), 5232; https://doi.org/10.3390/ma18225232 - 19 Nov 2025

Viewed by 286

Abstract

Cross-laminated timber (CLT) panels, composed of orthogonally bonded layers, are often used in civil engineering and tall constructions owing to their sustainability, prefabrication advantages and favourable mechanical performance. However, their multilayered, anisotropic and shear-compliant nature presents significant challenges for accurate structural modelling and [...] Read more.

Cross-laminated timber (CLT) panels, composed of orthogonally bonded layers, are often used in civil engineering and tall constructions owing to their sustainability, prefabrication advantages and favourable mechanical performance. However, their multilayered, anisotropic and shear-compliant nature presents significant challenges for accurate structural modelling and performance prediction. This study presents an advanced numerical approach to analysing the bending behaviour of CLT panels using the finite element method (FEM) in combination with the classical laminate theory. The proposed plate model was implemented in FlexPDE and validated through a series of three-point bending experiments on three-layer spruce panels. Further verification was conducted using commercial FEM software—Dlubal, incorporating both linear elastic and non-linear damage models, and Abaqus, where a three-dimensional solid model with a cohesive zone formulation captured progressive delamination and local failure in the glued layers. Comparison of the experimental data and numerical simulations revealed strong agreement in load–deflection behaviour, stiffness evolution and damage localisation. The framework we developed accurately reproduces both the global and the local mechanical responses of CLT panels while maintaining computational efficiency. Our results confirm the reliability of laminate theory-based FEM formulations in the design, optimisation and safety assessment of cross-laminated timber structures in building applications. Full article

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

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4 pages, 149 KB

Open AccessEditorial

Fabrication and Properties of Functional Coatings Under Extreme Conditions

by Chaoyang Chen, Lingjie Chen and Guoqin Cao

Materials 2025, 18(22), 5231; https://doi.org/10.3390/ma18225231 - 19 Nov 2025

Viewed by 324

Abstract

The advancement of aerospace, marine engineering, and advanced energy systems hinges on material performance under extreme service conditions (intense thermal exposure, severe corrosion, high mechanical stress) [...] Full article

(This article belongs to the Special Issue Fabrication and Properties of Functional Coatings Under Extreme Conditions)

16 pages, 3649 KB

Open AccessArticle

Ultra-Strong Transparent ZnAl₂O₄ Glass-Ceramics via Controlled Crystallization and Ion Exchange

by Ivan Veselov, Georgiy Shakhgildyan, Vitaliy Savinkov, Nikita Golubev, Kirill Tregubov, Daniil Vinogradov, Leon Avakyan, Michael Ojovan, Manasi Ghosh and Vladimir Sigaev

Materials 2025, 18(22), 5230; https://doi.org/10.3390/ma18225230 - 19 Nov 2025

Viewed by 525

Abstract

Enhancing the mechanical strength of transparent glass-ceramics (TGCs) without compromising their optical performance remains a key challenge for advanced optical and photonic materials. Among aluminosilicate systems, ZnO–MgO–Al₂O₃–SiO₂ (ZMAS) glasses are particularly attractive due to their ability to form [...] Read more.

Enhancing the mechanical strength of transparent glass-ceramics (TGCs) without compromising their optical performance remains a key challenge for advanced optical and photonic materials. Among aluminosilicate systems, ZnO–MgO–Al₂O₃–SiO₂ (ZMAS) glasses are particularly attractive due to their ability to form ZnAl₂O₄-based nanostructures; however, their ion-exchange (IE) strengthening has not been systematically explored due to the absence of single-charged cations in their composition. In this study, a sodium-modified ZMAS glass was developed to enable efficient chemical strengthening while preserving glass-forming ability and optical clarity. Controlled two-stage heat treatment produced TGCs containing 5 mol% Na₂O, composed solely of ZnAl₂O₄ (gahnite) nanocrystals with an average size of 4–5 nm. The obtained TGCs showed a Vickers hardness of ~8.5 GPa, increasing to ~10–10.5 GPa after ion exchange in molten KNO₃ at 450 °C, without changes in phase composition or optical transmittance. Compared with literature data on alkali-containing TGCs, the developed material demonstrates a higher hardness level while maintaining full transparency. The results reveal a practical route toward chemically strengthened ZnAl₂O₄-based glass-ceramics combining optical clarity, high hardness, and damage tolerance for optical, photonic, and protective applications. Full article

(This article belongs to the Special Issue Synergy in Polyphase Materials: Harnessing the Power of Glass and Ceramics)

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20 pages, 3615 KB

Open AccessArticle

OVI-Guided Tuning of Oxygen Vacancies in Fly Ash Denitrification Catalysts

by Zhanfeng Qi, Shuyang Wang, Xiuli Guo, Guancheng Li and Jingliang Li

Materials 2025, 18(22), 5229; https://doi.org/10.3390/ma18225229 - 19 Nov 2025

Viewed by 321

Abstract

Denitrification catalysts are essential for reducing NO_x emissions from combustion and protecting air quality. This study introduces and validates an Oxygen Vacancy Index (OVI) that quantifies redox-active vacancies and guides defect engineering in fly ash-derived catalysts. We apply a simple [...] Read more.

Denitrification catalysts are essential for reducing NO_x emissions from combustion and protecting air quality. This study introduces and validates an Oxygen Vacancy Index (OVI) that quantifies redox-active vacancies and guides defect engineering in fly ash-derived catalysts. We apply a simple cascade strategy to tune defect types; procedural details are reported in Methods rather than in the abstract. The optimized catalyst shows an over-twofold increase in OVI compared with raw fly ash. Surface-related changes and point/line defects contribute comparably (≈one-third each) to the explained variance. OVI positively correlates with NO conversion, and the optimized material delivers high NO conversion at 400 °C. These results establish a quantitative process–structure–performance link. Looking ahead, the OVI framework can guide defect design in other waste-derived catalysts and support scale-up to monolith coatings and pilot-scale units. This OVI-guided route provides a simple, low-cost path to robust fly ash catalysts for industrial NO_x control. Full article

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

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15 pages, 5585 KB

Open AccessArticle

Structure and Energetics of Chemically Functionalized Silicene: Combined Density Functional Theory and Machine Learning Approach

by Paweł Wojciechowski, Andrzej Bobyk and Mariusz Krawiec

Materials 2025, 18(22), 5228; https://doi.org/10.3390/ma18225228 - 19 Nov 2025

Viewed by 452

Abstract

It is crucial to control and comprehend the interaction between elemental adsorbates and two-dimensional materials to drive future generations of electronic, sensing, and energy applications. One such material, particularly interesting from the perspective of tunability, is silicene—the silicon-based cousin of graphene. In this [...] Read more.

It is crucial to control and comprehend the interaction between elemental adsorbates and two-dimensional materials to drive future generations of electronic, sensing, and energy applications. One such material, particularly interesting from the perspective of tunability, is silicene—the silicon-based cousin of graphene. In this work, we investigate nearly 2000 atomic adsorption models on silicene via a combination of density functional theory (DFT) and machine learning (ML). Different systems with varied adsorption geometries, element identities, and surface coverages were optimized using spin-polarized DFT, and the most stable configurations were selected based on adsorption energy. This information was used to train various ML models, including tree-based models and artificial neural networks, to predict adsorption geometry (classification) and adsorption energy (regression). The current hybrid DFT + ML approach provides a transferable framework for high-throughput screening of element-functionalized silicene and other 2D surfaces, which is of immense importance in directing surface modification strategies in electronic and catalytic device engineering. Full article

(This article belongs to the Special Issue Advances in Two-Dimensional Materials: Design, Properties, and Applications)

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30 pages, 2649 KB

Open AccessSystematic Review

Evaluating the Clinical Efficacy of Membrane-Assisted Regenerative Therapy in Peri-Implantitis Management: A Comprehensive Review Incorporating Systematic Review Evidence

by Young Joon Cho, Yong Tak Jeong, Hyun Nyun Woo, Hyun Woo Cho, Min Gu Kang, Sung-Min Hwang and Jae-Mok Lee

Materials 2025, 18(22), 5227; https://doi.org/10.3390/ma18225227 - 18 Nov 2025

Viewed by 480

Abstract

Peri-implantitis (PI) is characterized by inflammatory tissue destruction and alveolar bone loss surrounding dental implants, posing clinical challenges. To promote bone regeneration, clinicians often use resorbable or non-resorbable membranes in combination with bone grafts or biologic agents. Despite their widespread application in PI [...] Read more.

Peri-implantitis (PI) is characterized by inflammatory tissue destruction and alveolar bone loss surrounding dental implants, posing clinical challenges. To promote bone regeneration, clinicians often use resorbable or non-resorbable membranes in combination with bone grafts or biologic agents. Despite their widespread application in PI management, the clinical efficacy of these approaches remains uncertain. Therefore, this study aims to evaluate the role of membrane-assisted regenerative therapy in the management of PI. A systematic literature search was conducted in PubMed, Scopus, Cochrane Library, and Google Scholar following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA 2020) guidelines, with the protocol registered in PROSPERO (CRD420251089276). Sixty-nine studies met the inclusion criteria. The primary outcomes assessed were bone-fill gain and reduction in probing pocket depth (PPD). Although some studies reported improved bone-fill and PPD reduction with membrane-assisted regenerative therapy, the findings were not consistently significant. Future research should validate the clinical efficacy of membranes through well-designed randomized trials and develop advanced decontamination techniques and implant surface modifications that could enhance treatment predictability and patient outcomes. Overall, while membranes show potential clinical value in regenerative therapy, their necessity remains uncertain owing to variability in the current evidence. Full article

(This article belongs to the Special Issue Advanced Materials for Oral Application (3rd Edition))

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20 pages, 3051 KB

Open AccessArticle

Flexural Behavior of Steel-FRP Composite Bars (SFCB)-Reinforced Concrete Beams: FEA Incorporating Bond-Slip Effects

by Chaohao Bi, Shuo Xu, Yu Ling, Yicong Zhong, Linbo Hong and Yongjian Cai

Materials 2025, 18(22), 5226; https://doi.org/10.3390/ma18225226 - 18 Nov 2025

Viewed by 281

Abstract

To overcome the corrosion issues of conventional steel reinforcement and the brittleness of fiber-reinforced polymer (FRP) materials, steel-FRP composite bars (SFCBs) offer an innovative solution by combining the ductility of steel with the high strength and corrosion resistance of FRP. However, existing research [...] Read more.

To overcome the corrosion issues of conventional steel reinforcement and the brittleness of fiber-reinforced polymer (FRP) materials, steel-FRP composite bars (SFCBs) offer an innovative solution by combining the ductility of steel with the high strength and corrosion resistance of FRP. However, existing research primarily focuses on experimental investigations, with insufficient numerical simulations of SFCB-reinforced concrete beams, particularly regarding bond-slip effects at the SFCB-concrete interface—a critical mechanism governing composite action and structural performance. This study develops a finite element (FE) model incorporating SFCB-concrete bond-slip effects to analyze the influence of outer FRP layer thickness (0, 3, 5, and 7 mm) on the flexural performance of concrete beams. The FE model demonstrates good predictive accuracy, with errors in ultimate capacity and mid-span displacement within 7% and 8%, respectively. Both cracking and yield loads increase with FRP thickness, while the ultimate load peaks at 5 mm. At 7 mm, concrete crushing occurs before the SFCB reaches its ultimate strength. The ductility index decreases with greater FRP thickness due to increased elastic energy without enhanced plastic energy (fixed steel core area), thereby reducing overall ductility. These findings provide a theoretical basis for optimizing SFCB-reinforced concrete structural design. Full article

(This article belongs to the Special Issue Towards Sustainable Low-Carbon Concrete—Second Edition)

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