Materials

11 pages, 2728 KB

Open AccessArticle

Giant In-Plane Shrinkage Induced by Structural Phase Transformation in TbCoSi₂

by Lulu Liu, Dinghui Wang and Shoutao Zhang

Materials 2025, 18(21), 5064; https://doi.org/10.3390/ma18215064 - 6 Nov 2025

Viewed by 786

Metal-based materials, pivotal for industrialization and technological progress, confront the long-standing issue of high thermal expansion, which limits their application in advanced scenarios. With a century-long research history, negative thermal expansion materials, particularly those in intermetallic compounds, offer promising solutions for regulating thermal [...] Read more.

Metal-based materials, pivotal for industrialization and technological progress, confront the long-standing issue of high thermal expansion, which limits their application in advanced scenarios. With a century-long research history, negative thermal expansion materials, particularly those in intermetallic compounds, offer promising solutions for regulating thermal expansion. Here, we investigate polycrystalline TbCoSi₂ ingots, revealing a notable 3% in-plane shrinkage from 223 K to 298 K induced by structural phase transitions. Temperature-dependent XRD and Rietveld refinement identify a low-temperature Pbcm space group structure, and the drastic a-axis shrinkage during the phase transition drives the in-plane contraction. Macroscopic magnetic measurements and first-principles calculations reveal an antiferromagnetic structure below 13.7 K, with magnetic and structural phase transitions being independent. These findings present a metal-based weakly magnetic material for precise thermal expansion control, particularly in the uniaxial direction. Full article

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32 pages, 5848 KB

Open AccessArticle

Porous Refractories Synthesized Using Rice Husk and Rice Husk Processing Products

by Svetlana Yefremova, Sergey Yermishin, Askhat Kablanbekov, Baimakhan Satbaev, Nurgali Shalabaev and Serik Satbaev

Materials 2025, 18(21), 5063; https://doi.org/10.3390/ma18215063 - 6 Nov 2025

Cited by 2 | Viewed by 1523

Abstract

In recent years, research in the field of the sustainable production of refractory ceramics has become topical. Significant attention has been paid to the use of secondary raw materials for obtaining high-quality materials. The purpose of the current study was to develop new [...] Read more.

In recent years, research in the field of the sustainable production of refractory ceramics has become topical. Significant attention has been paid to the use of secondary raw materials for obtaining high-quality materials. The purpose of the current study was to develop new high-temperature porous materials based on the magnesium sulfate-refractory clay–chamotte–aluminum system using environmentally friendly raw components. To synthesize porous refractories, rice husk and the by-products of its thermal processing were used as substitutes for ingredients usually introduced into the composition of high-temperature materials. Ground rice husk was used as both a burnout additive and a silica source. It was added to the mixture instead of chamotte. An organic condensate from rice husk pyrolysis was used as a binder. A sodium silicate solution, after activating pyrolyzed rice husk with alkali, was also tested as a binder. These liquid ingredients served as replacements for lignosulfonate and liquid glass. The new raw material components and the porous refractories obtained with their use were studied using methods of chemical analysis, XRD, GC-MS, TA, SEM, and EDS. Standard methods for studying the properties of refractories were used to evaluate the physicomechanical and thermal characteristics of the experimental materials. The sample with the maximum content of rice husk (14.4 wt.%) and organic condensate from its pyrolysis (10.5 wt.%) demonstrated promising properties as a light porous refractory: an apparent porosity of 44%, a volumetric weight of 1.1 g·cm⁻³, compressive strength of 2.1 MPa, tensile strength in bending of 4.5 MPa, bond strength of 0.01 MPa, thermal shock resistance of 155 thermal cycles, and thermal conductivity of 0.05 W (m·K)⁻¹. It can be used as a prospective thermal insulating material. Full article

(This article belongs to the Section Advanced and Functional Ceramics and Glasses)

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15 pages, 1270 KB

Open AccessArticle

Structural–Phase Transformations in Stainless Steel CF8 Under Ion Implantation and Thermal Treatment

by Irina Manakova, Mikhail Vereshchak, Gaukhar Yeshmanova and Zhandos Tleubergenov

Materials 2025, 18(21), 5062; https://doi.org/10.3390/ma18215062 - 6 Nov 2025

Cited by 1 | Viewed by 762

Abstract

The γ ⟶ α′-transformation under implantation of austenitic-ferritic steel CF8 with ⁵⁷Fe ions to fluences of 1 × 10¹⁶, 5 × 10¹⁶ and 1 × 10¹⁷ ion/cm², as well as the reverse α′ ⟶ γ–transformation under [...] Read more.

The γ ⟶ α′-transformation under implantation of austenitic-ferritic steel CF8 with ⁵⁷Fe ions to fluences of 1 × 10¹⁶, 5 × 10¹⁶ and 1 × 10¹⁷ ion/cm², as well as the reverse α′ ⟶ γ–transformation under thermal treatment, was studied using transmission Mössbauer spectroscopy (MS), conversion electron Mössbauer spectroscopy (CEMS), and X-ray diffraction (XRD) methods. It was found that implantation, which causes radiation damage with 36 dpa, results in the formation of α′-martensite. At higher fluences of implanted ions, the amount of α′-martensite increased, reaching 86 at.% within the irradiated layer. Annealing in the temperature range of 600–850 °C resulted in the observed reverse transformation of α′-martensite to γ-austenite. The dependence of the average effective magnetic field on the annealing temperature was established. Full article

(This article belongs to the Section Metals and Alloys)

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33 pages, 8769 KB

Open AccessArticle

Microstructure of Additively Manufactured SUS316L Stainless Steel with SrO Heterogeneous Nucleation Site Particles

by Yoshimi Watanabe, Shimon Sekiyama, Mami Mihara-Narita, Tomokazu Moritani, Hisashi Sato, Kaname Fujii, Ayahito Saikai and Masato Ono

Materials 2025, 18(21), 5061; https://doi.org/10.3390/ma18215061 - 6 Nov 2025

Cited by 1 | Viewed by 1017

Abstract

It is known that the addition of SrO heterogeneous nucleation site particles can refine the microstructure of SUS316L stainless steel additively manufactured (AMed) by powder bed fusion (PBF). In this study, this idea was confirmed by directed energy deposition (DED). However, there are [...] Read more.

It is known that the addition of SrO heterogeneous nucleation site particles can refine the microstructure of SUS316L stainless steel additively manufactured (AMed) by powder bed fusion (PBF). In this study, this idea was confirmed by directed energy deposition (DED). However, there are several types of DED machines, and the energy system and the material supply system of these machines are different depending on each machine. In this study, the grain refinement behavior and the formability of AMed SUS316L stainless steel with the addition of SrO heterogeneous nucleation site particles are evaluated using a single-beam type LAMDA 200 machine and a multi-beam type ALPION Series machine. The size of the melt pool made by the ALPION Series machine is smaller than that of the LAMDA 200 machine, which results in a shorter residence time in the liquid state of the melt pool for the ALPION Series machine. The grains formed in the inoculated sample manufactured by the ALPION Series machine under the unidirectional scanning strategy are found to be refined compared to those in the uninoculated sample. On the other hand, it is found that the formation of defects and the crystallographic texture observed in the samples manufactured by the LAMDA 200 machine is suppressed by the addition of SrO heterogeneous nucleation site particles. These differences between the ALPION Series and LAMDA 200 machines would come from the differences in the melting state, including temperature, cooling conditions, and re-heating. Full article

(This article belongs to the Section Metals and Alloys)

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25 pages, 7755 KB

Open AccessArticle

The Influence of Process Conditions and Reinforcement Characteristics on the Densification and Mechanical Properties of Powder Metallurgy SiC_p/Al Composites

by Liuxu Cao, Qingsong Dai, Qiwen Liang and Xiaoyong Zhang

Materials 2025, 18(21), 5060; https://doi.org/10.3390/ma18215060 - 6 Nov 2025

Cited by 1 | Viewed by 899

Abstract

Compared to pure aluminum powder, aluminum alloy powders exhibit higher strength and hardness, which leads to greater difficulty in plastic deformation during cold compaction, consequently impairing green compact formation and subsequent densification. This study introduces pure aluminum powder into the raw material system [...] Read more.

Compared to pure aluminum powder, aluminum alloy powders exhibit higher strength and hardness, which leads to greater difficulty in plastic deformation during cold compaction, consequently impairing green compact formation and subsequent densification. This study introduces pure aluminum powder into the raw material system based on 2024 aluminum alloy powder and SiC powder, effectively improving the powder compaction characteristics. A systematic investigation was conducted to examine the effects of sintering temperature (460–640 °C) and holding time (5–120 min) during pressureless sintering on the sintering shrinkage, relative density, mechanical properties, and microstructure of SiC_p/Al composites reinforced with 35 wt.% of 31.9 μm SiC particles. The results indicate that sintering at 600 °C for 30 min constitutes the optimal process condition, achieving effective interparticle bonding while preventing coarsening of both precipitates and pores. Subsequent hot pressing effectively enhanced the relative density and mechanical properties of the sintered preforms, achieving a maximum tensile strength of 343 MPa, which represents an improvement of over 70% compared to the sintered-only state. For the hot-pressed state, elevated levels of SiC particle content and size compromised its mechanical performance. This work demonstrates a highly operable and industrially viable processing route for manufacturing aluminum matrix composites using alloy powders. Full article

(This article belongs to the Special Issue Study on Advanced Metal Matrix Composites (3rd Edition))

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13 pages, 2889 KB

Open AccessArticle

Analysis of Energy Consumption in the Cutting Zone During Turning Bearing Steel 16MnCr5

by Anna Mičietová, Mário Drbúl, Mária Čilliková and Miroslav Neslušan

Materials 2025, 18(21), 5059; https://doi.org/10.3390/ma18215059 - 6 Nov 2025

Cited by 2 | Viewed by 514

Abstract

This paper deals with the consumption of energy during the turning of low-alloyed steel 16MnCr5. The study employs the earlier reported methodology for the decomposition of energy in cutting during turning. The energy for chip formation, as well as the energy consumed in [...] Read more.

This paper deals with the consumption of energy during the turning of low-alloyed steel 16MnCr5. The study employs the earlier reported methodology for the decomposition of energy in cutting during turning. The energy for chip formation, as well as the energy consumed in the interface between the tool flank and produced surfaces, can be singled out. The paper investigates the turning process as a function of the cutting conditions as well as the variable cutting edge geometry. It was found that the integration of a chip former valuably contributes to the lower chip ratios, as well as the more favourable shape of chips. The lower energy consumed in the tool flank region for the tool with the integrated chip former results in lower normal and shear forces despite the higher cutting edge radius. However, the differences in the surface strain accumulation expressed in terms of the dislocation density and residual stress depth profiles are only subtle. Full article

(This article belongs to the Section Metals and Alloys)

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16 pages, 2519 KB

Open AccessReview

Glass Formation in the GeSe₂–As₂Se₃–MeCh Systems (Me = Cu, Ag, Zn, Cd, Sn, Pb; Ch = S, Se, Te)

by Lilia Aljihmani

Materials 2025, 18(21), 5058; https://doi.org/10.3390/ma18215058 - 6 Nov 2025

Viewed by 857

Abstract

The creation of novel, effective materials with specific properties is necessary to advance technology. To do this, objective regularities between the material’s composition, structure, and properties must be found. A comparative analysis of glass-forming regions, arranged according to the systematic substitution of one [...] Read more.

The creation of novel, effective materials with specific properties is necessary to advance technology. To do this, objective regularities between the material’s composition, structure, and properties must be found. A comparative analysis of glass-forming regions, arranged according to the systematic substitution of one element by its analog within a periodic system subgroup, provides a useful framework for discussing trends in glass formation in semiconductor alloys. In this review, the information on the glass formation in the chalcogenide systems GeSe₂–As₂Se₃–MeCh, where Me = Cu, Ag, Zn, Cd, Sn, Pb; Ch = Se, Te, was subjected to a thorough comparative analysis to establish objective patterns in the change in the glass-forming ability in these systems. The effect of MeCh on the formation of glass in the binary system GeSe₂–As₂Se₃ was traced. Full article

(This article belongs to the Section Advanced and Functional Ceramics and Glasses)

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13 pages, 1853 KB

Open AccessArticle

Non-Destructive Evaluation of Damage and Electricity Characteristics in 4H-SiC Induced by Ion Irradiation via Raman Spectroscopy

by Hui Dai, Zhiyan Hou, Xinqing Han, Jiacheng Liang, Anxin Jiao, Zhixian Wei, Chen Wu, Ke Sun, Yong Liu and Xuelin Wang

Materials 2025, 18(21), 5057; https://doi.org/10.3390/ma18215057 - 6 Nov 2025

Cited by 1 | Viewed by 966

Abstract

To optimize the design of silicon carbide (SiC) devices for applications in space and nuclear environments, this work introduces varying degrees of lattice damage into SiC through controlled irradiation conditions, with Raman spectroscopy revealing its damage evolution behavior and quantitatively characterizing the increasing [...] Read more.

To optimize the design of silicon carbide (SiC) devices for applications in space and nuclear environments, this work introduces varying degrees of lattice damage into SiC through controlled irradiation conditions, with Raman spectroscopy revealing its damage evolution behavior and quantitatively characterizing the increasing trend of disorder with irradiation fluences. Fine analysis of the A₁(LO) phonon mode demonstrates that proliferation of irradiation-induced acceptor centers and accumulation of scattering defects lead to significant attenuation of carrier concentration and mobility (cross-verified by Hall effect measurements), thereby causing degradation in electrical conductivity of SiC. Subsequent electrical testing confirms an orders-of-magnitude reduction in conductivity, establishing a quantitative correlation model with total disorder quantified by the DI/DS model. The non-destructive Raman technique enables simultaneous acquisition of material damage characteristics and quantitative electrical performance degradation, providing a predictive framework for the evolution of electrical behavior for SiC under irradiation damage, with significant implications for optimizing irradiation-hardened device designs. Full article

(This article belongs to the Section Advanced Materials Characterization)

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23 pages, 18157 KB

Open AccessArticle

Proportional Multiaxial Fatigue Behavior and Life Prediction of Laser Powder Bed Fusion Ti-6Al-4V with Critical Plane-Based Building Direction Variations

by Tian-Hao Ma, Yu-Xin Wang, Wei Zhang, Jian-Ping Zhao and Chang-Yu Zhou

Materials 2025, 18(21), 5056; https://doi.org/10.3390/ma18215056 - 6 Nov 2025

Cited by 2 | Viewed by 858

Abstract

Laser powder bed fusion (L-PBF) is an additive manufacturing technique that enables the fabrication of complex geometries through a layer-by-layer approach, overcoming limitations of conventional manufacturing. In this study, multiaxial low-cycle fatigue (MLCF) tests were conducted on L-PBF Ti-6Al-4V (Ti64) specimens built in [...] Read more.

Laser powder bed fusion (L-PBF) is an additive manufacturing technique that enables the fabrication of complex geometries through a layer-by-layer approach, overcoming limitations of conventional manufacturing. In this study, multiaxial low-cycle fatigue (MLCF) tests were conducted on L-PBF Ti-6Al-4V (Ti64) specimens built in four different orientations, selected based on critical plane orientations identified from rolled titanium. Under proportional strain-controlled loading, the cyclic softening behavior, mean stress response, and fracture mechanisms of the material were systematically investigated. The results show that L-PBF Ti64 exhibits a three-stage softening characteristic (continuous softening, stable, and rapid softening). Fatigue cracks primarily initiate from inner-surface lack-of-fusion defects. Crack propagation shows cleavage and quasi-cleavage characteristics with tearing ridges, river patterns, and multi-directional striations. Proposed KBMP life prediction model, incorporating λ and building direction parameters, was developed. The KBMP-λ model demonstrates optimal accuracy, providing a reliable tool for the design of L-PBF titanium components subjected to complex multiaxial fatigue loading with relative errors within 20%. Full article

(This article belongs to the Special Issue Mechanical Behavior and Multiscale Modeling of Advanced Structural Materials)

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11 pages, 648 KB

Open AccessArticle

Permeation of 2-Butoxyethanol Through Multiple Layers of a Disposable Nitrile Glove Material and a Single Layer of Microflex 93-260

by Eun Jin Song Kuramoto and Shane Que Hee

Materials 2025, 18(21), 5055; https://doi.org/10.3390/ma18215055 - 6 Nov 2025

Viewed by 915

Abstract

Double gloving of disposable gloves occurs in healthcare when extra protection is required against carcinogens, sensitizers, pathogens and sharps. Triple gloving is much rarer. The resistances of single, double and triple layers of disposable nitrile glove material against 2-butoxyethanol (2-BE) were compared with [...] Read more.

Double gloving of disposable gloves occurs in healthcare when extra protection is required against carcinogens, sensitizers, pathogens and sharps. Triple gloving is much rarer. The resistances of single, double and triple layers of disposable nitrile glove material against 2-butoxyethanol (2-BE) were compared with the resistance of a single layer of Microflex 93-260 (Microflex). Three 2.54 cm ASTM F739 permeation cells with closed-loop water collection without recirculation in a moving tray water bath at 35.0 ± 0.5 °C facilitated the permeation relative to a blank cell. Capillary gas chromatography/mass spectrometry allowed the determination of the standardized breakthrough time (SBT), steady state permeation rate (SSPR) and cumulated permeated mass/area (CPM/A) by 30 min. Two nitrile layers (267 ± 14 µm) were about the same thickness as the Microflex layer (249 ± 6 µm). Statistical analysis showed equivalence at p ≤ 0.05 of the multiple layers and the Microflex layer relative to average SBT and CPM/A by 30 min, all such comparisons with the single nitrile layer also being statistically different. The triple layer had an average SSPR or post-breakthrough permeation rate 8 times lower than its single layer, while that for the Microflex layer was 1.5 times lower. Thus, the Microflex layer in terms of CPM/A by 30 min at 210 ± 40 µg/cm² appeared closer to two nitrile layers (520 ± 560 µg/cm²) than three (93 ± 93 µg/cm²). Full article

(This article belongs to the Section Advanced Materials Characterization)

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22 pages, 10772 KB

Open AccessArticle

An Artificial Neural Network for Rapid Prediction of the 3D Transient Temperature Fields in Ship Hull Plate Line Heating Forming

by Zhe Yang, Hua Yuan, Zhenshuai Wei, Lichun Chang, Yao Zhao and Jiayi Liu

Materials 2025, 18(21), 5054; https://doi.org/10.3390/ma18215054 - 6 Nov 2025

Viewed by 969

Abstract

Line heating processes play a significant role in the fabrication of structural steel components, particularly in industries such as shipbuilding, aerospace, and automotive manufacturing, where dimensional accuracy and minimal defects are critical. Traditional methods, such as the finite element method (FEM) simulations, offer [...] Read more.

Line heating processes play a significant role in the fabrication of structural steel components, particularly in industries such as shipbuilding, aerospace, and automotive manufacturing, where dimensional accuracy and minimal defects are critical. Traditional methods, such as the finite element method (FEM) simulations, offer high-fidelity predictions but are hindered by prohibitive computational latency and the need for case-specific re-meshing. This study presents a physics-aware, data-driven neural network that delivers fast, high-fidelity temperature predictions across a broad operating envelope. Each spatiotemporal point is mapped to a one-dimensional feature vector. This vector encodes thermophysical properties, boundary influence factors, heatsource variables, and timing variables. All geometric features are expressed in a path-aligned local coordinate frame, and the inputs are appropriately normalized and nondimensionalized. A lightweight multilayer perceptron (MLP) is trained on FEM-generated induction heating data for steel plates with varying thickness and randomized paths. On a hold-out test set, the model achieves MAE = 0.60 °C, RMSE = 1.27 °C, and R2 = 0.995, with a narrow bootstrapped 99.7% error interval (−0.203 to −0.063 °C). Two independent experiments on an integrated heating and mechanical rolling forming (IHMRF) platform show strong agreement with thermocouple measurements and demonstrate generalization to a plate size not seen during training. Inference is approximately five orders of magnitude (~10⁵) faster than FEM, enabling near-real-time full-field reconstructions or targeted spatiotemporal queries. The approach supports rapid parameter optimization and advances intelligent line heating operations. Full article

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

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20 pages, 2126 KB

Open AccessArticle

Evaluation of Silkworm Cocoon-Derived Biochar as an Adsorbent for the Removal of Organic and Inorganic Contaminants from Rainwater

by Anna Marszałek, Ewa Puszczało, Mariusz Dudziak, Anna Pajdak and Jakub Frankowski

Materials 2025, 18(21), 5053; https://doi.org/10.3390/ma18215053 - 6 Nov 2025

Viewed by 930

Abstract

This study presents evaluation of biochar derived from silkworm cocoons for the adsorption of organic and inorganic contaminants from rainwater. The material was characterised using BET surface area analysis, scanning electron microscopy (SEM), and the point of zero charge (pH_PZC). The [...] Read more.

This study presents evaluation of biochar derived from silkworm cocoons for the adsorption of organic and inorganic contaminants from rainwater. The material was characterised using BET surface area analysis, scanning electron microscopy (SEM), and the point of zero charge (pH_PZC). The prepared biochar exhibited a well-developed surface area and demonstrated adsorption capacity toward both heavy metals and benzotriazole. The model rainwater was prepared by spiking real rainwater samples with Cu(II), Ni(II), Zn(II) ions, and benzotriazole (BT). Adsorption experiments were carried out under laboratory conditions to evaluate the effects of contact time, pH, and sorbent dosage. The experimental data were fitted to pseudo-first-order and pseudo-second-order kinetic models, as well as Langmuir/and Freundlich isotherms. The results showed that the adsorption of Cu(II) followed the Langmuir/Freundlich model, while the adsorption of Ni(II) benzotriazole was more consistent with the Freundlich model. Adsorption kinetics were best described by the pseudo-second-order model. The highest removal efficiencies were observed for Cu(II) (96%) and Ni(II) (88.8%), while Zn(II) removal was limited. Benzotriazole was also effectively adsorbed (97%), rapid adsorption occurred mainly within the first minute. Overall, the study highlights the selective adsorption behaviour of silkworm cocoon biochar and provides a comparative insight into the removal of organic and inorganic pollutants using a waste-derived adsorbent with surface properties comparable to those of activated carbon. Full article

(This article belongs to the Special Issue An Overview of Highly Porous Adsorbent Materials: Synthesis, Properties and Applications)

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24 pages, 3586 KB

Open AccessArticle

Valorization of Brewer’s Yeast Waste as a Low-Cost Biofiller for Polylactide: Analysis of Processing, Mechanical, and Thermal Properties

by Krzysztof Moraczewski, Małgorzata Łazarska, Magdalena Stepczyńska, Bartłomiej Jagodziński, Tomasz Karasiewicz and Cezary Gozdecki

Materials 2025, 18(21), 5052; https://doi.org/10.3390/ma18215052 - 6 Nov 2025

Viewed by 924

Abstract

The aim of this study was the valorization of brewer’s yeast waste as a low-cost, biodegradable filler for polylactide (PLA) and the evaluation of the effect of yeast biomass on the processing, mechanical, thermal properties, and biodegradation of the resulting composites. The materials [...] Read more.

The aim of this study was the valorization of brewer’s yeast waste as a low-cost, biodegradable filler for polylactide (PLA) and the evaluation of the effect of yeast biomass on the processing, mechanical, thermal properties, and biodegradation of the resulting composites. The materials were prepared using extrusion and injection molding techniques, with the addition of brewer’s yeast (Saccharomyces cerevisiae) in amounts ranging from 5 to 30 wt%. Fourier-transform infrared spectroscopy (FTIR) analysis revealed the absence of strong interfacial chemical interactions, indicating physical dispersion of the filler within the matrix. The addition of biomass significantly modified the properties of PLA. The results demonstrated increased melt flowability (melt flow rate increased from 18.8 to 39.8 g/10 min) and stiffness (a 13% increase in Young’s modulus for 20 wt%), accompanied by a considerable reduction in tensile strength (from 63.2 to 20.2 MPa) and impact strength (from 22.8 to 6.2 kJ/m²). Thermal analyses showed a systematic decrease in the glass transition temperature by approximately 5 °C and a dual effect of the filler on crystallization behavior. At low concentrations, the waste acted as a nucleating agent, while at higher loadings it limited crystallinity, leading to an amorphous structure. Thermal stability decreased with increasing biomass content (from 329.3 °C to 266.8 °C). Industrial composting tests indicated that at a 30 wt% yeast content, the mass loss (27.5%) was higher than that of neat PLA (25.5%), suggesting accelerated biodegradation. Despite the deterioration of mechanical performance, the developed biocomposites represent a promising material for single-use applications, combining low cost, easy processability, and an environmentally favorable profile consistent with the principles of the circular economy. Full article

(This article belongs to the Section Polymeric Materials)

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33 pages, 9908 KB

Open AccessArticle

Integrated Performance and Capability Analysis of Anticorrosive Cathodic Electrodeposition Coatings: Effect of Polymerization Variables

by Damián Peti, Gabriel Stolárik, Radoslav Vandžura, Miroslav Gombár and Michal Hatala

Materials 2025, 18(21), 5051; https://doi.org/10.3390/ma18215051 - 6 Nov 2025

Cited by 1 | Viewed by 1003

Abstract

The presented research delivers a comprehensive evaluation of anticorrosive cathodic electrodeposition (CED) coatings through an integrated performance and process capability analysis—an approach that remains extremely limited in the literature, particularly in the context of statistically designed experiments (DoEs) applied to CED systems. This [...] Read more.

The presented research delivers a comprehensive evaluation of anticorrosive cathodic electrodeposition (CED) coatings through an integrated performance and process capability analysis—an approach that remains extremely limited in the literature, particularly in the context of statistically designed experiments (DoEs) applied to CED systems. This study therefore addresses a notable gap by focusing on the role of polymerization variables in determining coating quality through DoE to quantify the influence on coating thickness uniformity, adhesion integrity and impact resistance, while all other deposition parameters were rigorously controlled. Prior to coating application, all specimens were prepared and conditioned in accordance with ISO 1513:2010. Coating thickness was determined in compliance with ISO 2808:2019, adhesion was characterized by cross-cut methodology according to ISO 2409:2020 and dynamic mechanical resistance was evaluated using a falling-weight apparatus in accordance with ISO 6272-1:2011. The obtained datasets were subjected to statistical capability analysis within the PalstatCAQ environment, providing Cp, Cpk, Pp and Ppk indices in line with ISO 22514-7:2021 and IATF 16949:2016 requirements. Results evidenced non-linear dependencies of thickness formation on curing parameters, with potential capability indices (Cp > 1.8; Pp ≈ 1.4) indicating favorable process dispersion, while performance indices (Cpk < 0.5; Ppk < 0.4) revealed systematic mean shifts and deviations from normality confirmed by Shapiro–Wilk and Anderson–Darling tests. Adhesion testing demonstrated a direct correlation between curing conditions and interfacial bonding, reaching ISO Grade 0 classification. Complementary impact resistance assessments corroborated these findings, showing that insufficient curing induced extensive cracking and delamination. Furthermore, SEM–EDX analysis performed on Sample n.3 of X₂ variable confirmed the chemical integrity and multilayered structure of the CED coating. Full article

(This article belongs to the Special Issue Enhanced Properties of Advanced Materials via Surface Modification and Composite Coatings)

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12 pages, 2975 KB

Open AccessArticle

Quantitative Measurement of the Tack for Carbon Fiber Reinforced Epoxy Prepreg by Using a Compression-to-Tension Method

by Xueming Wang, Guoli Li, Xiu Liu, Xiaofeng Lin and Baolin Pang

Materials 2025, 18(21), 5050; https://doi.org/10.3390/ma18215050 - 6 Nov 2025

Viewed by 833

Abstract

Prepreg tack is an important process quality parameter for prepregs during laying. Aiming at the current lack of standardized testing for prepreg tack, this paper established a quantitative testing method for prepreg tack—a compression-to-tension method—and proposed a parameter of Compression Tack Index as [...] Read more.

Prepreg tack is an important process quality parameter for prepregs during laying. Aiming at the current lack of standardized testing for prepreg tack, this paper established a quantitative testing method for prepreg tack—a compression-to-tension method—and proposed a parameter of Compression Tack Index as a quantitative evaluation index for prepreg tack. The prepreg/prepreg tack and prepreg/metal tack of carbon fiber reinforced epoxy prepregs were evaluated and the applicability of this compression-to-tension method was verified, comparing it with the qualitative testing method by vertical metal plates. The results show that the compression-to-tension method is suitable for quantitative testing of the tack for unidirectional prepregs and fabric prepregs, with good repeatability and stability of test results, and is not affected by personnel changes. Considering that tack characterization based only on the separation process cannot accurately evaluate the tack of different materials, Compression Tack Index is an accurate parameter that characterizes the prepreg tack because it can reflect the process of tack formation and tack separation. Compared with the vertical metal plate method, the discrimination of the test results by the compression-to-tension method is significant. The tack of the slitting prepreg without polyethylene film coating is lower than that of the mother prepreg (one-meter-width prepreg) with polyethylene film. Full article

(This article belongs to the Section Advanced Composites)

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19 pages, 3967 KB

Open AccessArticle

Innovative Seismic Solutions for Precast Structures: Experimental and Numerical Studies on Beam–Column Joints

by Roberto Nascimbene and Davide Bellotti

Materials 2025, 18(21), 5049; https://doi.org/10.3390/ma18215049 - 6 Nov 2025

Cited by 2 | Viewed by 1157

Abstract

This study presents a novel structural framing solution designed to improve seismic energy dissipation and limit displacements, aiming to serve as an effective alternative to traditional precast systems employing pendulum-based isolation. While pendulum mechanisms mitigate seismic forces by decoupling the superstructure from ground [...] Read more.

This study presents a novel structural framing solution designed to improve seismic energy dissipation and limit displacements, aiming to serve as an effective alternative to traditional precast systems employing pendulum-based isolation. While pendulum mechanisms mitigate seismic forces by decoupling the superstructure from ground motion, they are typically characterized by high implementation costs, mechanical complexity, and post-event maintenance challenges. In contrast, the proposed approach integrates seismic performance enhancements within the structural frame itself, removing the dependency on external isolation components. The system leverages a combination of pinned and semi-rigid beam-to-column joints that are tailored for use within dry precast construction technologies. These connection types not only support rapid and labor-efficient assembly but also, when properly detailed, offer robust hysteretic behavior and deformation control under dynamic loading. The research includes both experimental testing and numerical simulations focused on the cyclic response of these connections, enabling a comprehensive understanding of their role in dissipating energy and delaying damage progression. Recognizing the industry’s frequent emphasis on construction speed and upfront cost-efficiency, often at the cost of long-term reparability, this work introduces an alternative framework that emphasizes resilience without compromising construction practicality. The resulting system demonstrates improved post-earthquake functionality and reduced downtime, making it a promising and economically viable option for seismic applications in precast construction. This advancement supports current trends toward performance-based design and enhances the structural reliability of dry-assembled systems in seismic regions. Full article

(This article belongs to the Special Issue Study on Mechanical Properties of Concrete Structures and RC Beams)

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23 pages, 9151 KB

Open AccessArticle

Durability Considerations in Replacing Blast Furnace Slag with Low-Grade Calcined Clay and Natural Pozzolan in Quaternary Cements

by Juan Manuel Etcheverry, Laurent Detemmerman, Krist Degezelle, Vadim Grigorjev, Laurena De Brabandere and Nele De Belie

Materials 2025, 18(21), 5048; https://doi.org/10.3390/ma18215048 - 5 Nov 2025

Viewed by 1051

Abstract

Belgium and the EU-27 face a shortage of suitable supplementary cementitious materials (SCMs) capable of supporting high levels of Portland cement substitution. To reduce CO₂ emissions from the cement industry, blended cements incorporating low-grade calcined clay, limestone, and lava (a natural pozzolan) [...] Read more.

Belgium and the EU-27 face a shortage of suitable supplementary cementitious materials (SCMs) capable of supporting high levels of Portland cement substitution. To reduce CO₂ emissions from the cement industry, blended cements incorporating low-grade calcined clay, limestone, and lava (a natural pozzolan) are investigated. Calcined clay is combined with limestone to produce a limestone–calcined clay cement (LC3). The reactivity of these new blends is assessed using isothermal calorimetry and compared to a reference blend with ground-granulated blast-furnace slag (GGBFS). Results show that mixtures with calcined clay develop slightly lower 28-day strength than those with GGBFS, while blends with lava exhibit strength gains only at later ages due to delayed pozzolanic activity. Overall, concrete made with low-grade calcined clay and lava achieves comparable compressive strength to the reference (CEM III/A), but with higher capillary porosity, leading to increased water absorption, drying shrinkage, and reduced freeze–thaw resistance. Despite these durability limitations, the sustainability assessment reveals that the LC3 mix with low-grade clay and lava has a lower global warming potential per unit strength at 28 days than CEM III/A and is competitive with CEM III/B. Full article

(This article belongs to the Special Issue Advances in Waste Materials’ Valorization)

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16 pages, 9679 KB

Open AccessArticle

Effects of Surface Rearrangement on H and O Adsorption on Cu and Pd Nanoparticles

by Nadezhda Vladimirovna Dokhlikova, Andrey Konstantinovich Gatin, Sergey Yurievich Sarvadiy, Ekaterina Igorevna Rudenko, Dinara Tastaibek, Polina Konstantinovna Ignat’eva and Maxim Vyacheslavovich Grishin

Materials 2025, 18(21), 5047; https://doi.org/10.3390/ma18215047 - 5 Nov 2025

Viewed by 896

Abstract

Atomic effects determining the adsorption of hydrogen and oxygen atoms on (111), (100), (110), and (211) surfaces of Cu and Pd have been studied using quantum chemical simulations. The deformation of the (111) and (100) surfaces during adatom bonding enhances the bond strength [...] Read more.

Atomic effects determining the adsorption of hydrogen and oxygen atoms on (111), (100), (110), and (211) surfaces of Cu and Pd have been studied using quantum chemical simulations. The deformation of the (111) and (100) surfaces during adatom bonding enhances the bond strength at active sites with high coordination numbers. In contrast, the deformation of the (110) and (211) surfaces does not exhibit a strong tendency. The atomic contribution of the nearest-neighbor environment depends on the square magnitude of the interaction matrix element,

V_{a d}^{2}

. A high

V_{a d}^{2}

value increases the proportion of repulsive interactions within the metal adsorption complexes, leading to a decrease in the coordination number of the most stable adsorption site. Full article

(This article belongs to the Special Issue Materials Science Advancements Through Density Functional Theory)

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18 pages, 6420 KB

Open AccessArticle

Development of Composite Thermocouple Materials Using PEDOT:PSS and Bi₂Te₃ for Wearables Thermopiles

by Olga Rac-Rumijowska, Piotr Markowski, Karol Rauch, Patrycja Suchorska-Woźniak and Andrzej Dziedzic

Materials 2025, 18(21), 5046; https://doi.org/10.3390/ma18215046 - 5 Nov 2025

Viewed by 2920

Abstract

This paper presents results on the preparation of thermoelectric composite materials for flexible and wearable electronics applications. Composite materials in the form of pastes for screen printing or stencil printing were made from a mixture of PEDOT:PSS paste and Bi₂Te₃ [...] Read more.

This paper presents results on the preparation of thermoelectric composite materials for flexible and wearable electronics applications. Composite materials in the form of pastes for screen printing or stencil printing were made from a mixture of PEDOT:PSS paste and Bi₂Te₃ powder. The pastes showed good adhesion both to polyimide foil (Kapton) and polyester fabric substrates. Depending on the composition and the substrate used, the pastes had a sheet resistance of 26–264 Ω/sq, a Seebeck coefficient of 14–45 μV/K and a power factor of 0.05–0.8 μW/mK². The obtained pastes enabled the fabrication of textile thermopiles using Ag and PEDOT:PSS/Bi₂Te₃ materials for both arms. The output voltage of the obtained thermopiles on textile and foil substrates was 6–8 mV at a temperature gradient of 100 °C, and the output power was 0.01–0.12 μW. Energy harvesting from the human–ambient temperature gradient using the developed generators yielded promising results, with output voltages around 0.3 mV. Full article

(This article belongs to the Section Smart Materials)

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18 pages, 3004 KB

Open AccessArticle

A New Penetration Depth Method Using Proctor Compaction Test for Determining the Optimal Starting Time of Hardening Topping in Concrete Flooring

by Agnieszka Michalik and Jacek Zychowicz

Materials 2025, 18(21), 5045; https://doi.org/10.3390/ma18215045 - 5 Nov 2025

Viewed by 790

Abstract

This article presents a development and validation of a method to determine the starting time for hardening concrete flooring mechanically floated using the Dry Shake Topping technique. Until now, an informal method based on shoeprint penetration depth of 3–4 mm into the hardening [...] Read more.

This article presents a development and validation of a method to determine the starting time for hardening concrete flooring mechanically floated using the Dry Shake Topping technique. Until now, an informal method based on shoeprint penetration depth of 3–4 mm into the hardening concrete floor has been used in practice, but it is prone to significant errors. The probe time method described in the literature also has multiple limitations and drawbacks. Currently, there is no scientifically verified method for accurately determining the setting time of concrete mix and its early compressive strength. This gap poses a research problem because incorrect early timing of topping floating leads to further defects in concrete flooring. Through various laboratory, pilot, and technical-scale tests, a new method was developed. According to this method, floating should begin when the penetration depth of the Proctor Compaction Test Apparatus in the concrete mix reaches 4–7 mm. This penetration depth corresponds to the point at which the hardening concrete mix achieves sufficient strength to support the floating equipment while remaining plastic enough to ensure a strong bond between the topping and concrete layers. The article presents correlations between the Proctor Compaction Test results and the early strength of young concrete. It also explains practical on-site application of the method, providing immediate results without the need for interpolation. This method can be applied to any concrete mix intended for use in concrete flooring. Full article

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

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20 pages, 6012 KB

Open AccessArticle

Feasibility of Employing Semi-Hard Magnetic Materials for Hysteresis Magnetic Clutches in Railway Systems

by Paweł Pistelok and Marcin Adamiak

Materials 2025, 18(21), 5044; https://doi.org/10.3390/ma18215044 - 5 Nov 2025

Viewed by 843

Abstract

This paper introduces innovative approaches to the design of railway point machines, with particular emphasis on the implementation of multi-component AlNiCoFe alloys, classified as semi-hard magnetic materials. A comprehensive review of existing mechanisms for mechanical force transmission—from the electric motor to the throwing [...] Read more.

This paper introduces innovative approaches to the design of railway point machines, with particular emphasis on the implementation of multi-component AlNiCoFe alloys, classified as semi-hard magnetic materials. A comprehensive review of existing mechanisms for mechanical force transmission—from the electric motor to the throwing bar—was conducted. The inherent limitations of conventional dry friction clutches, commonly used in current point machine designs, are critically analyzed. Furthermore, the feasibility of employing multi-component AlNiCoFe alloys as functional materials in hysteresis magnetic clutches is examined, with a view toward enhancing the reliability and performance of railway point actuation systems. A review of diagnostic methods for railway point machines was conducted to evaluate the potential application of a novel magnetic torque limiter as a means to eliminate maintenance activities typically required for systems utilizing dry friction clutches. Experimental research was performed on AlNiCoFe alloys employed as the hysteresis layer in the proposed torque limiter. Microstructural and compositional analyses were carried out using scanning electron microscopy (SEM), Energy Dispersive Spectroscopy (EDS), and X-ray Diffraction (XRD) to determine the crystallographic structure, chemical composition, and selected physical properties of the tested materials. The hysteresis loops of the tested materials were measured using a Vibrating Sample Magnetometer (VSM) over a wide temperature range. A prototype magnetic clutch, functioning as a torque limiter in a railway point machine, was developed and presented. The operational characteristics—specifically the throwing force as a function of time—were recorded for a railway point machine equipped with an electromechanical module incorporating the new magnetic torque limiter. The advantages of the proposed solution in terms of force transmission and overall system performance in railway point machine design were analyzed and discussed. Full article

(This article belongs to the Section Metals and Alloys)

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30 pages, 13805 KB

Open AccessArticle

Structure–Property Relationships of Polymer-Modified Cement Concrete (PCC) Under Service Temperature Conditions

by Alexander Flohr, Savitha Devarajamohalla Narayana, Luise Göbel and Andrea Osburg

Materials 2025, 18(21), 5043; https://doi.org/10.3390/ma18215043 - 5 Nov 2025

Cited by 1 | Viewed by 1120

Abstract

Polymer modification is a widely employed technique for optimizing specific properties of mortars and concretes. This process entails the precise tailoring of the binder phase to the requirements of the given application. The polymer addition exerts a significant influence on both the fresh [...] Read more.

Polymer modification is a widely employed technique for optimizing specific properties of mortars and concretes. This process entails the precise tailoring of the binder phase to the requirements of the given application. The polymer addition exerts a significant influence on both the fresh and hardened states of mortar or concrete. In this study, a systematic, stepwise experimental campaign was carried out to investigate the effects of three different polymer dispersions on the time-dependent properties of cement pastes, mortars, and concretes at different temperatures in the service temperature range. The experimental findings demonstrate that polymer modifications significantly influence the behavior of hardened cement-based materials. In general, the strength and deformation resistance decreased with increasing temperature, with this effect being more pronounced in polymer-modified materials. This is indicative of the intrinsic temperature-dependent behavior of the polymers. Temperatures of −20 °C induced specific alterations in the mechanical behavior, particularly evident in the flexural strength and in the early age stiffness development of the pastes, mortars, and concretes. This phenomenon is attributed to the freezing of pore water, which results in the stiffening of the binder structure. In summary, the findings offer significant insights into the structure–property relationships of polymer-modified cement-based materials in relation to temperature. Full article

(This article belongs to the Special Issue Effect of Additives/Admixtures on the Properties of Concretes and Cementitious Composites—Second Edition)

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16 pages, 2645 KB

Open AccessEditor’s ChoiceArticle

Enhanced Superconductivity near the Pressure-Tuned Quantum Critical Point of Charge-Density-Wave Order in Cu_1-δTe (δ = 0.016)

by Kwang-Tak Kim, Yeahan Sur, Ingyu Choi, Zifan Wang, Sangjin Kim, Dilip Bhoi, Duck Young Kim and Kee Hoon Kim

Materials 2025, 18(21), 5042; https://doi.org/10.3390/ma18215042 - 5 Nov 2025

Viewed by 971

Abstract

We have investigated the evolution of CDW states and structural phases in a Cu-deficient Cu_1-δTe (δ = 0.016) by employing high-pressure experiments and first-principles calculations. Raman scattering results reveal that the vulcanite structure at ambient pressure starts to change into the [...] Read more.

We have investigated the evolution of CDW states and structural phases in a Cu-deficient Cu_1-δTe (δ = 0.016) by employing high-pressure experiments and first-principles calculations. Raman scattering results reveal that the vulcanite structure at ambient pressure starts to change into the Cu-deficient rickardite (r-CuTe) structure from 6.7 GPa, which then becomes fully stabilized above 8.3 GPa. Resistivity data show that T_CDW1 (≈333 K) is systematically suppressed under high pressure, reaching zero at 5.9 GPa. In the pressure range of 5.2–8.2 GPa, a sharp resistivity drop due to superconductivity occurs at the onset temperature T_C = ~2.0–3.2 K. The maximum T_C = 3.2 K achieved at 5.6 GPa is clearly higher than that of CuTe (2.3 K), suggesting the importance of charge fluctuation in the vicinity of CDW suppression. At 7.5 GPa, another resistivity anomaly appears due to the emergence of a second CDW (CDW2) ordering at T_CDW2 = ~176 K, which exhibits a gradual increase to ~203 K with pressure increase up to 11.3 GPa. First-principles calculations on the Cu-deficient Cu₁₁Te₁₂ with the r-CuTe structure show that including on-site Coulomb repulsion is essential for incurring an unstable phonon mode relevant for stabilizing the CDW2 order. These results point out the important role of charge fluctuation in optimizing the pressure-induced superconductivity and that of Coulomb interaction in creating the competing CDW order in the Cu-deficient CuTe system. Full article

(This article belongs to the Section Materials Physics)

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30 pages, 978 KB

Open AccessArticle

Computational Strategy for Analyzing Effective Properties of Random Composites—Part II: Elasticity

by Roman Czapla, Piotr Drygaś, Simon Gluzman, Tomasz Ligocki and Vladimir Mityushev

Materials 2025, 18(21), 5041; https://doi.org/10.3390/ma18215041 - 5 Nov 2025

Cited by 4 | Viewed by 1004

Abstract

We suggest a novel strategy in the theory of elastic plane composites. The macroscopic properties are quantified, and an analytical–numerical algorithm to derive expressions for the effective constants is designed. The effective elastic constants of dispersed random composites are given by new analytical [...] Read more.

We suggest a novel strategy in the theory of elastic plane composites. The macroscopic properties are quantified, and an analytical–numerical algorithm to derive expressions for the effective constants is designed. The effective elastic constants of dispersed random composites are given by new analytical and approximate formulas where the dependence on the location of inclusions is explicitly shown in symbolic form. This essentially extends the results of previous numerical simulations for a fixed set of material constants and fixed locations of inclusions. This paper extends the analysis from Part I, which addressed dispersed random conducting composites, to the two-dimensional elastic composites. Hill’s concept of Representative Volume Element (RVE), traditionally used in elastic composites, is revised. It is rigorously demonstrated that the RVE must be a fundamental domain of the plane torus, for instance, a periodicity parallelogram, since other shapes of RVE may lead to incorrect values of the effective constants. The effective tensors of the elasticity theory are decomposed into geometrical and physical parts, represented by structural sums and material constants of the components. Novel computational methodology based on such decomposition is applied to a two-phase isotropic composite with non-overlapping circular inclusions embedded in an elastic matrix. For the first time, it is demonstrated explicitly how the effective tensors depend on the geometric probabilistic distributions of inclusions and the computational protocols involved. Analytical polynomial formulas for the effective shear modulus for the moderate concentration of inclusions are transformed using the resummation methods into practical expressions valid for all concentrations of inclusions. The critical index for the effective shear modulus is calculated from the polynomials derived for the modulus. Full article

(This article belongs to the Special Issue Computational and Experimental Modeling of Interfaces and Joints in Advanced Materials)

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Graphical abstract

9 pages, 2220 KB

Open AccessCommunication

Stabilizing Zinc Anodes with Water-Soluble Polymers as an Electrolyte Additive

by Xueyan Li, Xiaojiang Chen, Senlong Zhang, Jinrong Wang, Zhuo Chen and Yuexian Song

Materials 2025, 18(21), 5040; https://doi.org/10.3390/ma18215040 - 5 Nov 2025

Cited by 1 | Viewed by 1169

Abstract

Water-induced corrosion and zinc dendrite formation seriously disrupt the Zn plating/stripping process at the anode/electrolyte interface, which results in the instability of the Zn metal anode in aqueous zinc-ion batteries. To address the issues of the zinc metal anode, three water-soluble polymers with [...] Read more.

Water-induced corrosion and zinc dendrite formation seriously disrupt the Zn plating/stripping process at the anode/electrolyte interface, which results in the instability of the Zn metal anode in aqueous zinc-ion batteries. To address the issues of the zinc metal anode, three water-soluble polymers with different hydrophilic groups—polyacrylic acid (PAA), polyacrylamide (PAM), and polyethylene glycol (PEG)—were designed as electrolyte additives in ZnSO₄ electrolytes. Among them, the PAA-based system exhibited an optimal electrochemical performance, achieving a stable cycling for more than 360 h at a current density of 5 mA cm⁻² with an areal capacity of 2 mA h cm⁻². This improvement could be attributed to its carboxyl groups, which effectively suppresses zinc dendrite growth, electrode corrosion, and side reactions, thereby enhancing the cycling performance of zinc-ion batteries. This work provides a reference for the optimization of zinc anodes in aqueous zinc-ion batteries. Full article

(This article belongs to the Topic Advanced Energy Storage in Aqueous Zinc Batteries)

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24 pages, 6443 KB

Open AccessArticle

Application of the Avrami Equation to the Dilatometric Analysis of ADI Austempering Kinetics

by Tomasz Wiktor, Andriy Burbelko and Artur Zaczyński

Materials 2025, 18(21), 5039; https://doi.org/10.3390/ma18215039 - 5 Nov 2025

Cited by 3 | Viewed by 986

Abstract

The method and results of evaluating the kinetics of austenite isothermal decomposition in austempered ductile iron (ADI) samples are presented based on the dimensional changes in austenitized and isothermally hardened cast iron samples. Experimental measurements were carried out on samples intended for the [...] Read more.

The method and results of evaluating the kinetics of austenite isothermal decomposition in austempered ductile iron (ADI) samples are presented based on the dimensional changes in austenitized and isothermally hardened cast iron samples. Experimental measurements were carried out on samples intended for the production of ADI castings under industrial conditions of ODLEWNIE POLSKIE S.A. A partial solution of the Kolmogorov–Johnson–Mehl–Avrami statistical theory of phase transformations as proposed by Avrami was applied to analyze the experimental results of dilatometric measurements. It is shown that Avrami diagrams can be used to evaluate changes in the kinetics of phase transformations occurring in ADI samples during the first stage of isothermal austenite decomposition. The application of the proposed method has made it possible to identify three steps of ausferrite growth during the first stage, with two statistically significant slowdowns. Using quantitative metallography methods, it is demonstrated that the slowdown in the rate of austenite decomposition during the transition from the first to the second step is related to the development of the microstructure of the metallic matrix of cast iron. Full article

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

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15 pages, 1867 KB

Open AccessArticle

Simplified Fracture Mechanics Analysis at the Zinc–Adhesive Interface in Galvanized Steel–CFRP Single-Lap Joints

by Maciej Adam Dybizbański and Katarzyna Rzeszut

Materials 2025, 18(21), 5038; https://doi.org/10.3390/ma18215038 - 5 Nov 2025

Viewed by 786

Abstract

Adhesively bonded joints between galvanized steel and carbon fiber-reinforced polymers (CFRPs) are critical in modern lightweight structures, but their performance is often limited by failure at the zinc–adhesive interface. This study presents a parametric analysis to investigate the influence of key geometric parameters [...] Read more.

Adhesively bonded joints between galvanized steel and carbon fiber-reinforced polymers (CFRPs) are critical in modern lightweight structures, but their performance is often limited by failure at the zinc–adhesive interface. This study presents a parametric analysis to investigate the influence of key geometric parameters on interfacial cracking in a single-lap joint (SLJ) configuration, employing a simplified analytical methodology based on Interface Fracture Mechanics (IFM). The model combines the Goland–Reissner approach for estimating crack-tip loads with highly simplified, constant shape functions to calculate the energy release rate (

G_{i n t}

) and phase angle (

ψ

). To provide a practical reference, experimental data from shear tests on S350 GD galvanized steel bonded to CFRP were used to estimate the range of interfacial fracture toughness for this material system. The parametric results demonstrate that, for a constant load, increasing the overlap length reduces the crack driving force (

G_{i n t}

), while increasing the adhesive thickness raises it. Crucially, the model indicates that a thicker adhesive layer shifts the fracture mode from shear- to opening-dominated, a trend consistent with the established mechanics of SLJs, where increased joint rotation amplifies peel stresses. The study concludes that while the use of constant shape functions limits the model’s quantitative accuracy, this simplified analytical framework effectively captures the qualitative influence of key geometric parameters on the joint’s fracture behavior. It serves as a valuable and resource-efficient tool for preliminary design explorations and for interpreting experimentally observed failure trends in galvanized steel–CFRP joints. Full article

(This article belongs to the Special Issue Advances in Experimental Investigation and Computational Modeling of Fiber-Reinforced Polymers and Composites—Second Edition)

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15 pages, 4087 KB

Open AccessArticle

Influence of Laser Processing Parameters on Surface Roughness and Color Formation in the Marked Zone

by Lyubomir Lazov, Nikolay Angelov, Emil Yankov, Tsanko Karadzhov, Dimcho Pulov and Dimitar Dichev

Materials 2025, 18(21), 5037; https://doi.org/10.3390/ma18215037 - 5 Nov 2025

Cited by 1 | Viewed by 975

Abstract

This study investigates the influence of laser processing parameters on the surface roughness and color formation of AISI 304 stainless steel. Experiments were conducted to explore how raster step, scanning speed, frequency, linear energy density, and overlap coefficient affect the surface characteristics of [...] Read more.

This study investigates the influence of laser processing parameters on the surface roughness and color formation of AISI 304 stainless steel. Experiments were conducted to explore how raster step, scanning speed, frequency, linear energy density, and overlap coefficient affect the surface characteristics of laser-marked zones. It was found that increasing the raster step from 20 µm to 80 µm led to a consistent increase in surface roughness (from 1.23 µm to 1.47 µm at 20 kHz and 25 mm/s), accompanied by a shift in color from dark brown to lighter yellow hues. In contrast, increasing scanning speed (from 25 mm/s to 125 mm/s) caused a nonlinear reduction in roughness (e.g., from 1.23 µm to 0.76 µm at 20 kHz and Δx = 20 µm), resulting in a lighter surface color. Frequency was identified as a critical factor; increasing it from 20 kHz to 100 kHz resulted in a threefold decrease in roughness (from 1.23 µm to 0.25 µm at 20 µm raster step and 125 mm/s), which correlated with a shift to brighter yellow tones. Higher linear energy density values (1.60–8.00 J/cm) increased roughness and darkened the surface color, while higher overlap coefficients produced the opposite trend. The study highlights the relationship between surface nanostructuring and the formation of stable interference colors, providing quantitative parameters for achieving desired chromatic effects. These findings establish a basis for the industrial application of laser color marking, where both aesthetic differentiation and functional enhancements—such as corrosion resistance, hydrophobicity, and antibacterial properties—are essential. Future research will focus on quantitatively evaluating the functional properties, including corrosion resistance, hydrophobicity, and durability, of the colored surfaces produced under optimized parameters. This research aims to further develop laser marking as a foundational tool for both aesthetic and functional surface engineering. Full article

(This article belongs to the Section Thin Films and Interfaces)

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22 pages, 2277 KB

Open AccessReview

Interfacial Rheology of Surfactant–Asphaltene Systems: State of the Art and Implications for Enhanced Oil Recovery

by Maria Isabel Sandoval Martinez, Ronald Mercado, Arlex Chaves-Guerrero and Hassan Hassanzadeh

Materials 2025, 18(21), 5036; https://doi.org/10.3390/ma18215036 - 5 Nov 2025

Cited by 5 | Viewed by 1301

Abstract

The study of the viscoelastic properties of surfactants in Enhanced Oil Recovery (EOR) has gained significant attention due to the role of interface elasticity in improving oil recovery. Interfacial rheology has been demonstrated to be a valuable tool for designing more efficient surfactant [...] Read more.

The study of the viscoelastic properties of surfactants in Enhanced Oil Recovery (EOR) has gained significant attention due to the role of interface elasticity in improving oil recovery. Interfacial rheology has been demonstrated to be a valuable tool for designing more efficient surfactant formulations in different industries. This review summarizes the principles and methods used to understand interfacial rheology and its impact on oil recovery. The paper explores key processes, interactions, and parameters that influence the formation of viscous or elastic films in the presence of active components in petroleum systems. The main findings highlight the importance of achieving optimal rigidity and viscoelastic properties at the interface, which promotes the formation of continuous phase threads that can be more easily swept. The review emphasizes the significance of understanding intermolecular interactions between surfactants and asphaltenes, as well as the impact of surfactant concentration on the formation of more viscous or elastic interfaces. Despite the valuable insights provided by interfacial rheology, further research is required to refine surfactant-based EOR strategies to enhance petroleum processing and recovery. Full article

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

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24 pages, 5716 KB

Open AccessArticle

Degradation Characteristics and Service Life Prediction of Desert Sand Concrete Under Load and Freeze–Thaw Conditions

by Zhengyang Xia, Yongjun Qin and Ling Luo

Materials 2025, 18(21), 5035; https://doi.org/10.3390/ma18215035 - 5 Nov 2025

Cited by 1 | Viewed by 917

Abstract

Concrete structures in western China often endure severe freeze–thaw cycles under sustained loading. However, the combined effects of desert sand admixtures and long-term stress on freeze–thaw durability are insufficiently investigated. The existing research has focused on the material modification of desert sand concrete [...] Read more.

Concrete structures in western China often endure severe freeze–thaw cycles under sustained loading. However, the combined effects of desert sand admixtures and long-term stress on freeze–thaw durability are insufficiently investigated. The existing research has focused on the material modification of desert sand concrete (DSC) or on the mechanical-environment coupling of ordinary concrete. This leaves a knowledge gap about how sustained compressive stress influences the macro- and mesoscale freeze–thaw behaviour of DSC. This study systematically investigated the freeze–thaw resistance of DSC under varying sustained compressive stresses. Testing methods and conditions were tailored to the climatic characteristics of China’s high-altitude cold regions. Freeze–thaw degradation was assessed using mass loss, relative dynamic modulus of elasticity, and compressive strength. Controlled loading effectively mitigated freeze damage. After cyclic freeze–thaw, the 0.3 and 0.5 stress groups retained 89.36% and 77.92% of their original compressive strength, respectively. Scanning electron microscopy, mercury porosimetry, and CT scanning revealed mesoscale damage mechanisms. Sustained loading optimized pore structure and enhanced compactness. A two-parameter Weibull probability model was then established to describe damage evolution patterns and assess the service life of desert sand concrete under regional climatic conditions. Full article

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

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