Materials

13 pages, 1891 KiB

Open AccessArticle

Microstructure-Based Magneto-Mechanical Modeling of Magnetorheological Elastomer Composites: A Comparable Analysis of Dipole and Maxwell Methods

by Shengwei Feng and Lizhi Sun

Materials 2025, 18(5), 1187; https://doi.org/10.3390/ma18051187 - 6 Mar 2025

Viewed by 546

Abstract

Magnetorheological elastomers (MREs) are smart composite materials with tunable mechanical properties by ferromagnetic particle interactions. This study applied the microstructure-based dipole and Maxwell methods to evaluate the magneto-mechanical coupling and magnetostrictive responses of MREs, focusing on various particle distributions. The finite element modeling [...] Read more.

Magnetorheological elastomers (MREs) are smart composite materials with tunable mechanical properties by ferromagnetic particle interactions. This study applied the microstructure-based dipole and Maxwell methods to evaluate the magneto-mechanical coupling and magnetostrictive responses of MREs, focusing on various particle distributions. The finite element modeling of representative volume elements with fixed volume fractions revealed that the straight chain microstructure exhibits the most significant magnetostrictive effect due to its low initial shear stiffness and significant magnetic force contributions. For particle separations exceeding three radii, the dipole and Maxwell methods yield consistent results for vertically or horizontally aligned particles. For particle separations greater than three radii, the dipole and Maxwell methods produce consistent results for vertically and horizontally aligned particles. However, discrepancies emerge for angled configurations and complex microstructures, with the largest deviation observed in the hexagonal particle distribution, where the two methods differ by approximately 27%. These findings highlight the importance of selecting appropriate modeling methods for optimizing MRE performance. Since anisotropic MREs with straight-chain alignments are the most widely used, our results confirm that the dipole method offers an efficient alternative to the Maxwell method for simulating these structures. Full article

(This article belongs to the Special Issue Smart Soft Materials: From Design to Applications)

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19 pages, 2536 KiB

Open AccessArticle

Anaerobic Biodegradation of Polylactic Acid-Based Items: A Specific Focus on Disposable Tableware Products

by Marica Falzarano, Alessandra Polettini, Raffaella Pomi, Andreina Rossi, Tatiana Zonfa, Maria Paola Bracciale, Serena Gabrielli, Fabrizio Sarasini and Jacopo Tirillò

Materials 2025, 18(5), 1186; https://doi.org/10.3390/ma18051186 - 6 Mar 2025

Viewed by 671

Abstract

The viability of anaerobic degradation treatment as an end-of-life option for commercial disposable bioplastic tableware, typically certified as compostable, was assessed. Two types of polylactic acid-based items were selected and tested under mesophilic conditions (38 °C) for 155 days, until reaching a plateau. [...] Read more.

The viability of anaerobic degradation treatment as an end-of-life option for commercial disposable bioplastic tableware, typically certified as compostable, was assessed. Two types of polylactic acid-based items were selected and tested under mesophilic conditions (38 °C) for 155 days, until reaching a plateau. Advanced chemical characterization of the products was performed with a combination of analytical techniques, i.e., microscopy, spectroscopy, and thermogravimetry. Two methods for calculating the biodegradation degree of the products were discussed and compared, using the biogas generated in the test and the total organic carbon (TOC) removal, respectively. The method based on TOC removal, resulting in a biodegradation degree ranging from 80.5% to 88.9%, was considered to more accurately describe the process. Given the complexity of assessing the biodegradation of a bioplastic product, an effort was made to derive correlations among the chemical–physical composition of the product, the biodegradation conditions, and the biodegradation yields/kinetics, with an aim to describe the process comprehensively. Statistical tools were also applied to derive additional considerations regarding the influence of the polymeric blend and digestion parameters on the biodegradation of bioplastic products. The identified data clusters, which were found to be grouped by the digestion temperature and the type of bioplastic, indicated specific biodegradation features of the investigated materials. Full article

(This article belongs to the Special Issue Recycling and Degradation of Polymeric Materials: Exploring Different Perspectives in Plastic Waste Management)

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16 pages, 3807 KiB

Open AccessArticle

A Study on the Effect of Conductive Particles on the Performance of Road-Suitable Barium Titanate/Polyvinylidene Fluoride Composite Materials

by Zhenhua Zhao, Rui Li, Chen Zhao and Jianzhong Pei

Materials 2025, 18(5), 1185; https://doi.org/10.3390/ma18051185 - 6 Mar 2025

Viewed by 668

Abstract

The design of piezoelectric roads is one of the future directions of smart roads. In order to ensure the environmentally friendly and long-lasting use of piezoelectric road materials, lead-free piezoelectric ceramics (barium titanate), polymer piezoelectric materials (polyvinylidene fluoride), and conductive particles (conductive carbon [...] Read more.

The design of piezoelectric roads is one of the future directions of smart roads. In order to ensure the environmentally friendly and long-lasting use of piezoelectric road materials, lead-free piezoelectric ceramics (barium titanate), polymer piezoelectric materials (polyvinylidene fluoride), and conductive particles (conductive carbon black and graphene) were used to prepare composite piezoelectric materials. The electrical performance was studied by the conductivity, dielectric properties, and piezoelectric properties of the composite materials. Then, the mechanical properties of the composite material were investigated by load compression tests. Finally, the microstructure of the composite materials was studied. The results showed that as the amount of conductive particles increased, the electrical performance was improved. However, further addition of conductive particles led to a decline in the electrical performance. The addition of conductive particles had a minimal effect on the mechanical properties of composite materials. The composite material met road use requirements. The overall structure of the composite materials was compact, with a clear wrapping effect of the polymer, and good interface compatibility. The addition of conductive carbon black and graphene had no significant impact on the structure of the composite materials. Full article

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11 pages, 6138 KiB

Open AccessArticle

Facile Synthesis of MoP and Its Composite Structure with Ru as an Efficient Electrocatalyst for Hydrogen Evolution Reaction in Both Acidic and Alkaline Conditions

by Pinyun Ren, Rui Wang, Yujie Yang, Tianyu Wang, Yilun Hong, Yi Zheng, Qianying Zheng, Xianpei Ren and Zhili Jia

Materials 2025, 18(5), 1184; https://doi.org/10.3390/ma18051184 - 6 Mar 2025

Viewed by 642

Abstract

Developing low-cost electrocatalysts for efficient hydrogen evolution in both acidic and alkaline conditions is crucial for water-electrolytic hydrogen applications. Herein, MoP was synthesized via a simple, low-cost, and green phosphorization route. More importantly, the Ru/MoP composite prepared using the as-synthesized MoP as a [...] Read more.

Developing low-cost electrocatalysts for efficient hydrogen evolution in both acidic and alkaline conditions is crucial for water-electrolytic hydrogen applications. Herein, MoP was synthesized via a simple, low-cost, and green phosphorization route. More importantly, the Ru/MoP composite prepared using the as-synthesized MoP as a reactant, which exhibited excellent catalytic activity for the hydrogen evolution reaction. It showed lower overpotentials of 108 and 55 mV at 10 mA·cm⁻² in acidic and alkaline solutions, respectively, which are superior to those of bare Ru and pristine MoP as well as comparable or even better than those of previously reported excellent Ru- or MoP-based catalysts. In addition, it also demonstrated small Tafel slopes of 52.6 mV dec⁻¹ and 67.9 mV dec⁻¹ in acidic and alkaline solutions, respectively, along with long-term stability. This work provides an effective and feasible route to design high-efficient MoP-based electrocatalysts for hydrogen evolution reaction. Full article

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18 pages, 8940 KiB

Open AccessArticle

Experimental and Model Calculation Research on Shrinkage of Hybrid Fiber-Reinforced Recycled Aggregate Concrete

by Lijuan Zhang, Meng He, Xinzhe Li, Changbin Li, Jun Zhao and Hai-Cui Wang

Materials 2025, 18(5), 1183; https://doi.org/10.3390/ma18051183 - 6 Mar 2025

Viewed by 421

Abstract

Recycled aggregate concrete (RAC), which is made by replacing all natural coarse and fine aggregates with recycled aggregate, plays a significant role in improving the recycling rate of construction materials, reducing carbon emissions from construction, and alleviating ecological degradation issues. However, due to [...] Read more.

Recycled aggregate concrete (RAC), which is made by replacing all natural coarse and fine aggregates with recycled aggregate, plays a significant role in improving the recycling rate of construction materials, reducing carbon emissions from construction, and alleviating ecological degradation issues. However, due to its low strength and significant shrinkage and deformation problems, RAC has limited application. The effort of fiber type, fiber admixture, and fiber hybridization on autogenous shrinkage were studied to improve the structural safety of building materials and broaden the application of RAC. Test results indicate that the shrinkage of RAC decreases with an increase in fiber admixture, and steel fiber-reinforced RAC is more resistant to shrinkage deformation than polypropylene fiber-reinforced RAC. The shrinkage deformation of the hybrid fiber group is smaller than that of the single fiber group, and the inhibition of shrinkage deformation is most effective when the volume fraction of steel fiber is 0.5% and the polypropylene fiber content is 1.5 kg/m³. At 120 days, the PF15SF05 mixture showed a 65.3% reduction in shrinkage compared with ordinary RAC. By merging the shrinkage deformation characteristics of fiber-reinforced RAC and introducing the fiber influence coefficient, three theoretical calculation models for autogenous shrinkage applicable to single and hybrid fiber-reinforced RAC were established based on the experimental data. Full article

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

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29 pages, 12606 KiB

Open AccessArticle

Study on Relationship Between Mechanical Properties and Water Absorption Characteristics of Mortars by Using Digital Image Correlation Method (DICM)

by Muhammad Usman, Hikaru Nakamura, Muhammad Shoaib Karam, Taito Miura and Go Igarashi

Materials 2025, 18(5), 1182; https://doi.org/10.3390/ma18051182 - 6 Mar 2025

Viewed by 917

Abstract

The evaluation of water absorption in concrete is regarded as an important indicator for assessing the causes of its deterioration and durability. Traditionally adopted methods for durability assessment in concrete materials, however, lack in providing real-time monitoring of the absorption process and information [...] Read more.

The evaluation of water absorption in concrete is regarded as an important indicator for assessing the causes of its deterioration and durability. Traditionally adopted methods for durability assessment in concrete materials, however, lack in providing real-time monitoring of the absorption process and information about the material deformability at surfaces (volumetric changes) caused by swelling in cement hydrates (i.e., C-S-H). In this study, a one-dimensional water absorption test was performed on small-size mortar specimens of three different strengths, and their top (flattened) surface was continuously monitored for volume changes by utilizing surface strain gauges along with the DICM. After the water absorption test, the same specimens were tested to determine mechanical properties such as compressive strength and Young’s modulus. Moreover, the water absorption characteristics, like depth/rate, were evaluated in DICM by tracing changes in waterfront positions with the progression of strains during the water absorption process in mortars. Additionally, the surface strain gauges confirmed the accuracy of strains evaluated by the DICM. The absorption characteristics obtained from observations in the DICM were correlated with the mechanical properties and expansion strain of the test specimens. The results indicated that the durability properties were not only related to the water absorption rate but also to the mechanical properties and volume changes due to saturation. Full article

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19 pages, 7569 KiB

Open AccessArticle

Vibration Analysis of Shape Memory Alloy Enhanced Multi-Layered Composite Beams with Asymmetric Material Behavior

by Kosar Samadi-Aghdam, Pouya Fahimi, Hamid Shahsavari, Davood Rahmatabadi and Mostafa Baghani

Materials 2025, 18(5), 1181; https://doi.org/10.3390/ma18051181 - 6 Mar 2025

Viewed by 594

Abstract

This study develops a finite element solution to analyze the vibration response of multi-layer shape memory alloy (SMA) composite beams. Using Euler–Bernoulli beam motion equations with tension–compression asymmetry, based on Poorasadion’s model, the Newmark method and Newton–Raphson technique are employed. Validating the model [...] Read more.

This study develops a finite element solution to analyze the vibration response of multi-layer shape memory alloy (SMA) composite beams. Using Euler–Bernoulli beam motion equations with tension–compression asymmetry, based on Poorasadion’s model, the Newmark method and Newton–Raphson technique are employed. Validating the model against ABAQUS/Standard results for a homogeneous SMA beam shows good agreement. This research explores the dynamic characteristics of bi-layer and tri-layer SMA beams, presenting deflection–time, stress–strain, and velocity–deflection profiles. SMAs’ hysteresis property effectively reduces early-stage vibration amplitudes, and their energy-dissipating feature during phase transformations makes them promising for controlling dynamic performance in engineering applications. Full article

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12 pages, 7307 KiB

Open AccessFeature PaperArticle

High Purity, Crystallinity and Electromechanical Sensitivity of Lead-Free (Ba_0.85Ca_0.15)(Zr_0.10Ti_0.90)O₃ Synthesized Using an EDTA/glycerol Modified Pechini Method

by Laura Caggiu, Costantino Cau, Marzia Mureddu, Stefano Enzo, Fabrizio Murgia, Lorena Pardo, Sonia Lopez-Esteban, Jose F. Bartolomé, Gabriele Mulas, Roberto Orrù and Sebastiano Garroni

Materials 2025, 18(5), 1180; https://doi.org/10.3390/ma18051180 - 6 Mar 2025

Viewed by 482

Abstract

A single (Ba_0.85Ca_0.15)(Zr_0.10Ti_0.90)O₃ phase material with a tetragonal structure is processed and synthesized with a modified Pechini method using ethylenediaminetetraacetic acid and glycerol as chelating and esterifying agents, respectively. The complete chemical transformation to [...] Read more.

A single (Ba_0.85Ca_0.15)(Zr_0.10Ti_0.90)O₃ phase material with a tetragonal structure is processed and synthesized with a modified Pechini method using ethylenediaminetetraacetic acid and glycerol as chelating and esterifying agents, respectively. The complete chemical transformation to the desired phase is achieved at 900 °C, which is 300 °C lower than conventional synthesis methods. Its consolidation, reaching up to 91% relative density, is carried out at 1400 °C. It is clearly demonstrated that the use of ethylenediaminetetraacetic acid and glycerol reagents is particularly beneficial for inducing a homogeneous grain size distribution (10 μm), which leads to very promising electromechanical properties (d₃₃ = 451 pC/N; d₃₁ = 160 pC/N; kp = 0.40;

ε'_{33}^{T}

= 4790 and Q_m = 358) of the densified system. Full article

(This article belongs to the Special Issue Design and Processing of Piezoelectric/Ferroelectric Ceramics)

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16 pages, 7306 KiB

Open AccessArticle

Fabrication of Cu/SiC Surface Composite via Thermo-Mechanical Process (Friction Stir Processing) for Heat Sink Application

by Harikishor Kumar, Abhishek Agarwal, Michel Kalenga Wa Kalenga, Rabindra Prasad, Parshant Kumar, L. Aslesha Chilakamarri and Balram Yelamasetti

Materials 2025, 18(5), 1179; https://doi.org/10.3390/ma18051179 - 6 Mar 2025

Viewed by 1096

Abstract

For the busting of heat, generated in electronic packages, relevant materials need to be developed. Metal matrix composites may be considered as an option to tailor the properties of a material (Cu) by incorporating an additional phase (SiC) for fulfilling the requirements of [...] Read more.

For the busting of heat, generated in electronic packages, relevant materials need to be developed. Metal matrix composites may be considered as an option to tailor the properties of a material (Cu) by incorporating an additional phase (SiC) for fulfilling the requirements of thermal management systems. The composite (Cu/SiC) was manufactured by friction stir processing. For good interfacial strength, the biggest challenge in the fabrication of Cu/SiC composite was to abolish the reaction between Cu and SiC. Being solid in nature, the process (friction stir processing) does not allow temperature to reach the interfacial interaction. Scanning electron microscopy, electron backscattered diffraction, and optical microscopy were used to characterise the composite for microstructural features (particle dispersion, phases present). To confirm the presence of reinforcement, EDS analysis was also performed on the composite. Results indicated the presence of Cu and SiC phases in the stir zone (SZ) with uniform and homogeneous separation of reinforcements. The composite displayed higher hardness, tensile strength, and wear resistance in comparison to unprocessed copper. However, ductility decreased due to high hardness in the composite. Full article

(This article belongs to the Special Issue Alloys and Composites: Structural and Functional Applications, Second Edition)

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24 pages, 18833 KiB

Open AccessArticle

Impact of Microstructure on the In Situ Formation of LDH Coatings on AZ91 Magnesium Alloy

by Nan Wang, Yulai Song, Anda Yu, Yong Tian and Hao Chen

Materials 2025, 18(5), 1178; https://doi.org/10.3390/ma18051178 - 6 Mar 2025

Viewed by 531

Abstract

Layered Double Hydroxide (LDH) coatings were synthesized on as-cast, T4 (solution treatment), and T6 (aging treatment) AZ91 magnesium alloys using a hydrothermal method. XRD (X-Ray Diffraction) and SEM (Scanning Electron Microscope) analyses showed that the large β-phases in as-cast AZ91 initially promoted LDH [...] Read more.

Layered Double Hydroxide (LDH) coatings were synthesized on as-cast, T4 (solution treatment), and T6 (aging treatment) AZ91 magnesium alloys using a hydrothermal method. XRD (X-Ray Diffraction) and SEM (Scanning Electron Microscope) analyses showed that the large β-phases in as-cast AZ91 initially promoted LDH growth via galvanic corrosion, but later compromised coating integrity. In contrast, T6 and T4 alloys, with refined microstructures, formed uniform and compact LDH coatings. Corrosion resistance was enhanced in T6 and T4 alloys, as evidenced by higher impedance from EIS (Electrochemical Impedance Spectroscopy), and HER (Hydrogen Evolution Reaction) tests, due to the formation of dense LDH layers. Full article

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5 pages, 8217 KiB

Open AccessEditorial

Recent Progress in Computational and Data Sciences for Additive Manufacturing

by Tuhin Mukherjee and Qianru Wu

Materials 2025, 18(5), 1177; https://doi.org/10.3390/ma18051177 - 6 Mar 2025

Viewed by 559

Abstract

Additive manufacturing (AM), often referred to as 3D printing, is a preferred technique for producing components that are challenging to manufacture through conventional methods [...] Full article

(This article belongs to the Special Issue Applications of Modeling and Machine Learning in Additive Manufacturing)

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23 pages, 9974 KiB

Open AccessArticle

Environmental Toxicity of Cement Nanocomposites Reinforced with Carbon Nanotubes

by Eryk Goldmann, Edyta Kudlek, Oktawian Bialas, Marcin Górski, Marcin Adamiak and Barbara Klemczak

Materials 2025, 18(5), 1176; https://doi.org/10.3390/ma18051176 - 6 Mar 2025

Viewed by 516

Abstract

The addition of carbon nanotubes (CNTs) to cement matrix brings multiple beneficial effects ranging from improving mechanical and physical properties to the creation of smart materials. When subjected to an erosive environment or as end-of-life waste, mortars with CNT addition might get released [...] Read more.

The addition of carbon nanotubes (CNTs) to cement matrix brings multiple beneficial effects ranging from improving mechanical and physical properties to the creation of smart materials. When subjected to an erosive environment or as end-of-life waste, mortars with CNT addition might get released into the environment and come in contact with surface waters. The assessment of the environmental impact of mortars reinforced with carbon nanotubes is an important factor concerning their sustainability, as it has not yet been addressed in the literature. The presented paper aims to assess the water toxicity of cement mortars with various dosages of 0.05 wt.%, 0.1 wt.%, and 0.2 wt.% of carbon nanotube. The effect of the quality of water dispersion of CNTs was also considered through two sonication times of the suspension: 20 min and 60 min. Tests using indicator organisms, Aliivibrio fischeri, Daphnia magna, and Lemna minor, were conducted on shredded and non-shredded mortars. The results reveal no to low toxicity for all tested mortars under the assumed framework of toxicity assessment. The toxicity results for samples containing CNTs were comparable to those without CNTs, indicating that the toxicity of mortars incorporating CNTs is not greater than that of conventional cement-based materials. The water toxicity of the cement mortars is rather connected with the washing away of the hydration products more than with the presence of carbon nanotubes. Full article

(This article belongs to the Special Issue Special Functional and Environmental Cement-Based Materials)

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30 pages, 14392 KiB

Open AccessArticle

High-Quality Perovskite Thin Films for NO₂ Detection: Optimizing Pulsed Laser Deposition of Pure and Sr-Doped LaMO₃ (M = Co, Fe)

by Lukasz Cieniek, Agnieszka Kopia, Kazimierz Kowalski and Tomasz Moskalewicz

Materials 2025, 18(5), 1175; https://doi.org/10.3390/ma18051175 - 6 Mar 2025

Viewed by 576

Abstract

This study investigates the structural and catalytic properties of pure and Sr-doped LaCoO₃ and LaFeO₃ thin films for potential use as resistive gas sensors. Thin films were deposited via pulsed laser deposition (PLD) and characterized using X-ray diffraction (XRD), X-ray photoelectron [...] Read more.

This study investigates the structural and catalytic properties of pure and Sr-doped LaCoO₃ and LaFeO₃ thin films for potential use as resistive gas sensors. Thin films were deposited via pulsed laser deposition (PLD) and characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), atomic force microscopy (AFM), nanoindentation, and scratch tests. XRD analysis confirmed the formation of the desired perovskite phases without secondary phases. XPS revealed the presence of La³⁺, Co³⁺/Co⁴⁺, Fe³⁺/Fe⁴⁺, and Sr²⁺ oxidation states. SEM and AFM imaging showed compact, nanostructured surfaces with varying morphologies (shape and size of surface irregularities) depending on the composition. Sr doping led to surface refinement and increased nanohardness and adhesion. Transmission electron microscopy (TEM) analysis confirmed the columnar growth of nanocrystalline films. Sr-doped LaCoO₃ demonstrated enhanced sensitivity and stability in the presence of NO₂ gas compared to pure LaCoO₃, as evidenced by electrical resistivity measurements within 230 ÷ 440 °C. At the same time, it was found that Sr doping stabilizes the catalytic activity of LaFeO₃ (in the range of 300 ÷ 350 °C), although its behavior in the presence of NO₂ differs from that of LaCo(Sr)O₃—especially in terms of response and recovery times. These findings highlight the potential of Sr-doped LaCoO₃ and LaFeO₃ thin films for NO₂ sensing applications. Full article

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19 pages, 13112 KiB

Open AccessArticle

The Effect of Mold Flux Wetting Conditions with Varying Crucible Materials on Crystallization

by Muhammad Anwarul Nazim, Arezoo Emdadi, Todd Sander and Ronald O’Malley

Materials 2025, 18(5), 1174; https://doi.org/10.3390/ma18051174 - 6 Mar 2025

Viewed by 638

Abstract

Understanding mold flux crystallization is essential for assessing heat transfer during steel casting. The complexity of the mold gap presents challenges in identifying the optimal testing method and nucleation type. This study investigates how variations in wetting properties influence nucleation dynamics, in particular [...] Read more.

Understanding mold flux crystallization is essential for assessing heat transfer during steel casting. The complexity of the mold gap presents challenges in identifying the optimal testing method and nucleation type. This study investigates how variations in wetting properties influence nucleation dynamics, in particular the wetting behaviors of mold flux in platinum and graphite crucibles and how they affect crystallization temperatures and solidification mechanisms. Advanced analytical techniques, including confocal laser scanning microscopy (CLSM), and differential scanning calorimetry (DSC) were employed to analyze nucleation under different conditions, with calibration using synthetic slag, Li₂SO₄, and thermodynamic equilibrium simulations. The findings highlight the crucial role of crucible materials in modifying nucleation energy barriers and undercooling requirements. These insights enhance the understanding of mold flux behavior, contributing to the refinement of testing methodologies and the optimization of heat transfer and solidification processes in continuous casting. Full article

(This article belongs to the Special Issue Achievements in Foundry Materials and Technologies)

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17 pages, 11431 KiB

Open AccessArticle

Process Parameters Analysis in Diamond Wire Saw Cutting NdFeB Magnet

by Chengwanli Peng, Guanzheng Li, Xingchun Zhang and Yufei Gao

Materials 2025, 18(5), 1173; https://doi.org/10.3390/ma18051173 - 6 Mar 2025

Viewed by 581

Abstract

Neodymium iron boron (NdFeB) magnetic materials are widely used in fields such as electronics, medical devices, power machinery, and hardware machinery. This paper conducted a three-factor and five-level orthogonal experiment on diamond wire saw cutting NdFeB to determine the influence degree of key [...] Read more.

Neodymium iron boron (NdFeB) magnetic materials are widely used in fields such as electronics, medical devices, power machinery, and hardware machinery. This paper conducted a three-factor and five-level orthogonal experiment on diamond wire saw cutting NdFeB to determine the influence degree of key factors such as workpiece feed rate, diamond wire speed, and workpiece processed size on the surface roughness Ra and waviness Wa of NdFeB slices. Further analysis was conducted on the influence of various parameters on the PV value (peak valley difference) of the waviness profile curve of the sawed surface. Finally, slicing processing was carried out under optimized process parameter combinations. The research results indicate that the primary and secondary order of process parameters affecting surface roughness Ra and waviness Wa is workpiece feed rate, wire speed, and sawed workpiece size, and the influence on the waviness PV value also shows a consistent trend. The optimal combination of processing parameters is workpiece feed rate of 0.1 mm·min⁻¹, wire speed of 1600 m·min⁻¹, and workpiece size of 10 mm. The obtained surface roughness Ra is 0.433 μm and the waviness Wa is 0.037 μm, respectively. The regression mathematical model for the waviness PV value is PV = 0.747 × v_s^−0.342 × v_w^0.546 × L^0.109. The research results of this paper provide an experimental basis and guidance for optimizing process parameters of sawing NdFeB. Full article

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

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24 pages, 17505 KiB

Open AccessArticle

Bayesian Updating of Fatigue Crack Growth Parameters for Failure Prognosis of Miter Gates

by Anita Brown, Brian Eick, Travis Fillmore and Hai Nguyen

Materials 2025, 18(5), 1172; https://doi.org/10.3390/ma18051172 - 6 Mar 2025

Viewed by 523

Abstract

Navigable waterways play a vital role in the efficient transportation of millions of tons of cargo annually. Inland traffic must pass through a lock, which consists of miter gates. Failures and closures of these gates can significantly disrupt waterborne commerce. Miter gates often [...] Read more.

Navigable waterways play a vital role in the efficient transportation of millions of tons of cargo annually. Inland traffic must pass through a lock, which consists of miter gates. Failures and closures of these gates can significantly disrupt waterborne commerce. Miter gates often experience fatigue cracking due to their loading and welded connections. Repairing every crack can lead to excessive miter gate downtime and serious economic impacts. However, if the rate of crack growth is shown to be sufficiently slow, e.g., using Paris’ law, immediate repairs may be deemed unnecessary, and this downtime can be avoided. Paris’ law is often obtained from laboratory testing with detailed crack measurements of specimens with relatively simple geometry. However, Paris’ law parameters for an in situ structure will likely deviate from those predicted from physical testing due to variations in loading and materials and a far more complicated geometry. To improve Paris’ law parameter prediction, this research proposes a framework that utilizes (1) convenient vision-based tracking of crack evolution both in the laboratory and the field and (2) numerical model estimation of stress intensity factors (SIFs). This study’s methodology provides an efficient tool for Paris’ law parameter prediction that can be updated as more data become available through vision-based monitoring and provide actionable information about the criticality of existing cracks. Full article

(This article belongs to the Special Issue Evaluation of Fatigue and Creep-Fatigue Damage of Steel)

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19 pages, 6014 KiB

Open AccessArticle

Preparation of Temperature Resistant Terpolymer Fracturing Fluid Thickener and Its Working Mechanism Study via Simulation Methods

by Bo Zhang, Bumin Guo, Guang’ai Wu, Shuan Li, Jinwei Shen, Susu Xing, Yujie Ying, Xiaoling Yang, Xinyang Zhang, Miaomiao Hu and Jintang Guo

Materials 2025, 18(5), 1171; https://doi.org/10.3390/ma18051171 - 6 Mar 2025

Viewed by 508

Abstract

To enhance oil and gas recovery, a novel hydrophobic terpolymer was synthesized via free radical polymerization. The terpolymer consists of acrylamide, acrylic acid, and hydrophobic monomers, and is used as a hydraulic fracturing fluid thickener for freshwater environments. Hydrophobic groups were introduced into [...] Read more.

To enhance oil and gas recovery, a novel hydrophobic terpolymer was synthesized via free radical polymerization. The terpolymer consists of acrylamide, acrylic acid, and hydrophobic monomers, and is used as a hydraulic fracturing fluid thickener for freshwater environments. Hydrophobic groups were introduced into terpolymer to improve its tackiness and temperature resistance. The conformation and key parameters of hydrophobic monomers at different temperatures were investigated through a combination of experiments and molecular dynamics simulations. These methods were employed to elucidate the mechanism behind its high-temperature resistance. The experiment results show that, at concentrations between 0.2% and 0.4%, significant intermolecular aggregation occurs, leading to a substantial increase in solution viscosity. Configuring the base fluid of synthetic polymer fracturing fluid with 1% doping, the apparent viscosities of the base fluid were 129.23 mPa·s and 133.11 mPa·s, respectively. The viscosity increase rate was 97%. The base fluid was crosslinked with 1.5% organozirconium crosslinker to form a gel. The controlled loss coefficient and loss velocity of the filter cake were C₃ = 0.84 × 10⁻³ m/min^1/2 and v_c = 1.40 × 10⁻⁴ m/min at 90 °C, meeting the technical requirements for water-based fracturing fluid. Molecular dynamics simulations revealed that the radius of gyration of the hydrophobically linked polymer chain segments decreases as the temperature increases. This is due to the increased thermal motion of the polymer chain segments, resulting in less stretching and intertwining of the chains. As a result, the polymer chains move more freely, which decreases the viscosity of the solution. In conclusion, the proposed fracturing fluid thickener system demonstrates excellent overall performance and shows significant potential for application in oil and gas recovery. Full article

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18 pages, 11112 KiB

Open AccessArticle

Dynamic Compressive Behavior, Constitutive Modeling, and Complete Failure Criterion of 30 Vol.% B₄C/2024Al Composite

by Qiang Yan, Zhihong Zhao, Tian Luo, Feng Li, Jianjun Zhao, Zhenlong Chao, Sanfeng Liu, Yong Mei and Fengjun Zhou

Materials 2025, 18(5), 1170; https://doi.org/10.3390/ma18051170 - 6 Mar 2025

Viewed by 529

Abstract

This study investigated the compressive behavior of 30 vol.% boron carbide (B₄C)/2024 aluminum (Al) composites under quasi-static and dynamic loading at different temperatures. Building on the experimental findings, the Johnson–Cook (JC) model was modified, and a complete failure criterion was proposed. [...] Read more.

This study investigated the compressive behavior of 30 vol.% boron carbide (B₄C)/2024 aluminum (Al) composites under quasi-static and dynamic loading at different temperatures. Building on the experimental findings, the Johnson–Cook (JC) model was modified, and a complete failure criterion was proposed. These were validated in Abaqus employing the user subroutine for hardening (VUHARD), which incorporated both the modified JC (MJC) model and the complete failure criterion. Experimental results revealed that strain softening was an important feature of the stress–strain curve. The analysis of mechanisms contributing to yield strength revealed that Taylor and load transfer mechanisms dominated, accounting for 89.6% of the total enhancement. Microstructural analysis identified particle fracture and matrix damage were the primary mechanisms driving material failure. Microcracks mainly propagated through the matrix and interface or directly through the ceramic particles and the matrix. The MJC model demonstrated high accuracy in describing the plastic deformation behavior of the composite, with a mean absolute error (MAE) below 15% under dynamic loading. Further simulation confirmed that finite element analyses using the VUHARD subroutine accurately captured the plastic deformation and crack propagation behaviors of the composite under dynamic loading. This study offers a novel approach to describe the plastic deformation and failure behaviors of ceramic-reinforced aluminum matrix composites under dynamic loading conditions. Full article

(This article belongs to the Special Issue Review and Feature Papers in "Metals and Alloys" Section (2nd Edition))

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14 pages, 5580 KiB

Open AccessArticle

Burst Ultrafast Laser Welding of Quartz Glass

by Xianshi Jia, Yinzhi Fu, Kai Li, Chengaonan Wang, Zhou Li, Cong Wang and Ji’an Duan

Materials 2025, 18(5), 1169; https://doi.org/10.3390/ma18051169 - 6 Mar 2025

Cited by 1 | Viewed by 651

Abstract

Ultrafast laser welding of transparent materials has been widely used in sensors, microfluidics, optics, etc. However, the existing ultrafast laser welding depths are limited by the short laser Rayleigh length, which makes it difficult to realize the joining of transparent materials in the [...] Read more.

Ultrafast laser welding of transparent materials has been widely used in sensors, microfluidics, optics, etc. However, the existing ultrafast laser welding depths are limited by the short laser Rayleigh length, which makes it difficult to realize the joining of transparent materials in the millimeter depth range and becomes a new challenge. Based on temporal shaping, we realized Burst mode ultrafast laser output with different sub-pulse numbers and explored the effect of different Burst modes on the welding performance using high-speed shadow in situ imaging. The experimental results show that the Burst mode femtosecond laser (twelve sub-pulses with a total energy of 28.9 μJ) of 238 fs, 1035 nm and 1000 kHz can form a molten structure with a maximum depth of 5 mm inside the quartz, and the welding strength can be higher than 18.18 MPa. In this context, we analyzed the transient process of forming teardrop molten structures inside transparent materials using high-speed shadow in situ imaging detection and systematically analyzed the fracture behavior of the samples. In addition, we further reveal the Burst femtosecond laser welding mechanism of transparent materials comprehensively by exploring the difference in welding performance under the effect of Burst modes with different sub-pulse numbers. This paper is the first to realize molten structures in the range of up to 5 mm, which is expected to provide a new welding method for curved surfaces and large-size transparent materials, helping to improve the packaging strength of photoelectric devices and the window strength of aerospace materials. Full article

(This article belongs to the Special Issue Advancements in Ultrasonic Testing for Metallurgical Materials)

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19 pages, 5657 KiB

Open AccessArticle

A Study on the Environmental Performance of an Asphalt Mixture Modified with Directly Added Waste Plastic

by Liting Yu, Haoyi Kang, Rui Li, Jianzhong Pei and Yizhi Du

Materials 2025, 18(5), 1168; https://doi.org/10.3390/ma18051168 - 6 Mar 2025

Viewed by 586

Abstract

The environmental pollution caused by waste plastics has raised widespread concern within the global academic community. The use of waste plastic in road construction is seen as a future trend for road materials, offering benefits such as energy conservation, pollution reduction, and the [...] Read more.

The environmental pollution caused by waste plastics has raised widespread concern within the global academic community. The use of waste plastic in road construction is seen as a future trend for road materials, offering benefits such as energy conservation, pollution reduction, and the enhanced high-temperature performance of asphalt mixtures. However, conventional testing methods have limited the scope of performance measurements for modified asphalt mixtures, and fewer studies have explored the pavement performance of such mixtures. This study evaluated the environmental performance of asphalt mixtures modified with waste plastics. A series of experiments, including rutting tests, low-temperature bending tests, water stability tests, and aging tests, demonstrated that the use of waste plastic-modified asphalt significantly improved high-temperature performance. Notably, with transition dispersants, the rutting resistance improved by 24.5%, and the low-temperature bending strength increased by 15.8%, demonstrating excellent anti-aging properties. Statistical analysis indicated that waste plastic-modified asphalt has superior high-temperature stability and good low-temperature crack resistance. Full article

(This article belongs to the Special Issue Sustainable Materials and Structures Used in Pavement Engineering (2nd Edition))

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30 pages, 4653 KiB

Open AccessReview

Nanoarchitectonics of Sustainable Food Packaging: Materials, Methods, and Environmental Factors

by Tangyu Yang and Andre G. Skirtach

Materials 2025, 18(5), 1167; https://doi.org/10.3390/ma18051167 - 6 Mar 2025

Viewed by 1120

Abstract

Nanoarchitectonics influences the properties of objects at micro- and even macro-scales, aiming to develop better structures for protection of product. Although its applications were analyzed in different areas, nanoarchitectonics of food packaging—the focus of this review—has not been discussed, to the best of [...] Read more.

Nanoarchitectonics influences the properties of objects at micro- and even macro-scales, aiming to develop better structures for protection of product. Although its applications were analyzed in different areas, nanoarchitectonics of food packaging—the focus of this review—has not been discussed, to the best of our knowledge. The (A) structural and (B) functional hierarchy of food packaging is discussed here for the enhancement of protection, extending shelf-life, and preserving the nutritional quality of diverse products including meat, fish, dairy, fruits, vegetables, gelled items, and beverages. Interestingly, the structure and design of packaging for these diverse products often possess similar principles and methods including active packaging, gas permeation control, sensor incorporation, UV/pulsed light processing, and thermal/plasma treatment. Here, nanoarchitechtonics serves as the unifying component, enabling protection against oxidation, light, microbial contamination, temperature, and mechanical actions. Finally, materials are an essential consideration in food packaging, particularly beyond commonly used polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polystyrene (PS), and polyvinyl chloride (PVC) plastics, with emphasis on biodegradable (polybutylene succinate (PBS), polyvinyl alcohol (PVA), polycaprolactone (PCL), and polybutylene adipate co-terephthalate (PBAT)) as well as green even edible (bio)-materials: polysaccharides (starch, cellulose, pectin, gum, zein, alginate, agar, galactan, ulvan, galactomannan, laccase, chitin, chitosan, hyaluronic acid, etc.). Nanoarchitechnotics design of these materials eventually determines the level of food protection as well as the sustainability of the processes. Marketing, safety, sustainability, and ethics are also discussed in the context of industrial viability and consumer satisfaction. Full article

(This article belongs to the Special Issue Nanoarchitectonics in Materials Science, Second Edition)

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15 pages, 4208 KiB

Open AccessArticle

Tuning the Mesopore Structure of Polyethylene Glycol Terephthalate (PET)-Derived Hard Carbon for High-Capacity Sodium-Ion Batteries

by Chupeng Wang, Mingsheng Luo, Shiqi Song, Maochong Tang, Xiaoxia Wang and Hui Liu

Materials 2025, 18(5), 1166; https://doi.org/10.3390/ma18051166 - 5 Mar 2025

Viewed by 625

Abstract

Hard carbon (HC) is considered to be a highly promising anode material for sodium-ion batteries. However, the synthesis conditions and pore structure regulation are still challenging for high-capacity sodium-ion storage. In this study, HCs using polyethylene glycol terephthalate (PET) as a carbon resource [...] Read more.

Hard carbon (HC) is considered to be a highly promising anode material for sodium-ion batteries. However, the synthesis conditions and pore structure regulation are still challenging for high-capacity sodium-ion storage. In this study, HCs using polyethylene glycol terephthalate (PET) as a carbon resource and ZnO as a nanopore template were synthesized and systematically investigated. By optimizing the additive amount of zinc gluconate, the starting material for ZnO, PET-derived HCs with a proper mesoporous structure were obtained. The as-prepared hard carbon demonstrated a high reversible capacity of 389.42 mAh·g⁻¹ at 20 mA·g⁻¹, with the plateau capacity accounting for 68%. After 75 cycles, the discharge capacity stabilized at 367.73 mAh·g⁻¹ with a retention ratio of 89.4%. The rate performance test indicated that a proper mesopore structure helped to improve the sodium-ion diffusion coefficient, effectively enhancing the charge–storage kinetics. This work provides a promising strategy for converting PET into valuable carbon materials for application in the field of renewable energy technology. Full article

(This article belongs to the Special Issue Electrode Materials for Advanced Rechargeable Batteries)

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28 pages, 4600 KiB

Open AccessArticle

Utilization of Coniferous and Deciduous Tree and Paper Ashes as Fillers of Rigid Polyurethane/Polyisocyanurate (PU/PIR) Foams

by Joanna Liszkowska, Magdalena Stepczyńska, Andrzej Trafarski, Justyna Miłek and Tomasz Karasiewicz

Materials 2025, 18(5), 1165; https://doi.org/10.3390/ma18051165 - 5 Mar 2025

Viewed by 1109

Abstract

Five series of rigid polyurethane–polyisocyanurate (RPU/PIR) foams were obtained. They were modified by ashes from burning paper (P) and wood: conifers (pine—S, spruce—S’) and deciduous trees (oak—D, birch—B). The ash was added to rigid polyurethane–polyisocyanurate foams (PU/PIR). In this way, five series of [...] Read more.

Five series of rigid polyurethane–polyisocyanurate (RPU/PIR) foams were obtained. They were modified by ashes from burning paper (P) and wood: conifers (pine—S, spruce—S’) and deciduous trees (oak—D, birch—B). The ash was added to rigid polyurethane–polyisocyanurate foams (PU/PIR). In this way, five series of foams with different ash contents (from 1 to 9% wt.) were obtained: PP, PS, PD, PS’, PB. The model foam (reference—W) was obtained without filler. The basic properties, physico-mechanical, and thermal properties of the ashes and obtained foams were examined. It was specified, among other things, the cellular structure by scanning electron microscopy (SEM), and changes in chemical structure by Fourier-transform infrared spectroscopy (FTIR) were compared. The obtained foams were also subjected to thermostating in a circulating air dryer in increased temperature (120 °C) for 48 h. Ash tests showed that their skeletal density is about 2.9 g/cm³, and the pH of their solutions ranges from 9 to 13. The varied color of the ashes affected the color of the foams. SEM-EDS tests showed the presence of magnesium, calcium, silicon, potassium, aluminum, phosphorus, sodium, and sulfur in the ashes. Foam tests showed that pine ash is the most beneficial for foams, because it increases their compressive strength three times compared to W foam and improves their thermal stability. All ashes cause the residue after combustion of the foams (retention) to increase and the range of combustion of the samples to decrease. Full article

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34 pages, 7433 KiB

Open AccessReview

Research Progress on the Surface Modification of Basalt Fibers and Composites: A Review

by Miaomiao Zhu, Mingming Zhu, Ruoxin Zhai, Wuwei Zhu and Jiabei He

Materials 2025, 18(5), 1164; https://doi.org/10.3390/ma18051164 - 5 Mar 2025

Viewed by 734

Abstract

Fiber-reinforced resin composites (FRRCs) are widely used in several fields such as construction, automotive, aerospace, and power. Basalt fiber (BF) has been increasingly used to replace artificial fibers such as glass fiber and carbon fiber in the production of BF-reinforced resin matrix composites [...] Read more.

Fiber-reinforced resin composites (FRRCs) are widely used in several fields such as construction, automotive, aerospace, and power. Basalt fiber (BF) has been increasingly used to replace artificial fibers such as glass fiber and carbon fiber in the production of BF-reinforced resin matrix composites (BFRRCs). This preference stems from its superior properties, including high temperature resistance, chemical stability, ease of manufacturing, cost-effectiveness, non-toxicity, and its natural, environmentally friendly characteristics. However, the chemical inertness of BF endows it with poor compatibility, adhesion, and dispersion in a resin matrix, leading to poor adhesion and a weak BF–resin interface. The interfacial bonding strength between BF and resin is an important parameter that determines the service performance of BFRRC. Therefore, the interfacial bonding strength between them can be improved through fiber modification, resin–matrix modification, mixed enhancers, etc., which consequently upgrade the mechanical properties, thermodynamic properties, and durability of BFRRC. In this review, first, the production process and properties of BFs are presented. Second, the mechanical properties, thermodynamic properties, and durability of BFRRC are introduced. Third, the modification effect of the non-destructive surface-modification technology of BF on BFRRC is presented herein. Finally, based on the current research status, the future research direction of BFRRC is proposed, including the development of high-performance composite materials, green manufacturing processes, and intelligent applications. Full article

(This article belongs to the Special Issue Synthesis, Sintering, and Characterization of Composites)

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24 pages, 3885 KiB

Open AccessArticle

Citrus-Fruit-Based Hydroxyapatite Anodization Coatings on Titanium Implants

by Amisha Parekh, Alp Tahincioglu, Chance Walters, Charles Chisolm, Scott Williamson, Amol V. Janorkar and Michael D. Roach

Materials 2025, 18(5), 1163; https://doi.org/10.3390/ma18051163 - 5 Mar 2025

Viewed by 603

Abstract

The increasing demand for titanium implants necessitates improved longevity. Plasma-sprayed hydroxyapatite coatings enhance implant osseointegration but are susceptible to delamination. Alternatively, anodized hydroxyapatite coatings have shown greater adhesion strengths. The present study aimed to develop anodized hydroxyapatite coatings on titanium using commercial calcium-fortified [...] Read more.

The increasing demand for titanium implants necessitates improved longevity. Plasma-sprayed hydroxyapatite coatings enhance implant osseointegration but are susceptible to delamination. Alternatively, anodized hydroxyapatite coatings have shown greater adhesion strengths. The present study aimed to develop anodized hydroxyapatite coatings on titanium using commercial calcium-fortified fruit juice as a calcium source. Varying the electrolyte compositions enabled the formation of four oxide groups with different predominate calcium compounds. Each oxide’s morphology, crystallinity, chemistry, molecular structure, and adhesion quality were compared and contrasted. Nanoscale SEM images revealed a progression from porous surface oxide to white surface deposits to petal-like hydroxyapatite structures with the changing anodization electrolytes. Oxide thickness evaluations showed progression from a single-layered oxide with low Ca-, P-, and Mg-dopant incorporations to bi-layered oxide structures with increased Ca-, P-, and Mg-dopant incorporation with changing electrolytes. The bi-layered oxide structures exhibited a titanium-dioxide-rich inner layer and calcium-compound-rich outer layers. Furthermore, indentation analyses confirmed good adhesion quality for three oxides. For the predominate hydroxyapatite oxides, FTIR analyses showed carbonate substitutions indicating the presence of bone-like apatite formation, and ICP-OES analyses revealed prolonged Ca and Mg release over 30 days. These Mg-enhanced carbonated apatite coatings show much promise to improve osseointegration and future implant lifetimes. Full article

(This article belongs to the Special Issue Biomaterials for Bone Tissue Engineering (Second Edition))

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24 pages, 5231 KiB

Open AccessArticle

Thermo-Mechanical Phase-Field Modeling of Fracture in High-Burnup UO₂ Fuels Under Transient Conditions

by Merve Gencturk, Nicholas Faulkner and Karim Ahmed

Materials 2025, 18(5), 1162; https://doi.org/10.3390/ma18051162 - 5 Mar 2025

Viewed by 547

Abstract

This study presents a novel multiphysics phase-field fracture model to analyze high-burnup uranium dioxide (UO₂) fuel behavior under transient reactor conditions. Fracture is treated as a stochastic phase transition, which inherently accounts for the random microstructural effects that lead to variations [...] Read more.

This study presents a novel multiphysics phase-field fracture model to analyze high-burnup uranium dioxide (UO₂) fuel behavior under transient reactor conditions. Fracture is treated as a stochastic phase transition, which inherently accounts for the random microstructural effects that lead to variations in the value of fracture strength. Moreover, the model takes into consideration the effects of temperature and burnup on thermal conductivity. Therefore, the model is able to predict crack initiation, propagation, and complex morphologies in response to thermal gradients and stress distributions. Several simulations were conducted to investigate the effects of operational and transient conditions on fracture behavior and the resulting cracking patterns. High-burnup fuels exhibit reduced thermal conductivity, elevating temperature gradients and resulting in extensive radial and circumferential cracks. Transient heating rates and temperatures significantly affect fracture patterns, with higher heating rates generating steeper gradients and more irregular crack trajectories. This approach provides critical insights into fuel integrity during accident scenarios and supports the safety evaluation of extended burnup limits. Full article

(This article belongs to the Special Issue Materials for Harsh Environments)

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18 pages, 6232 KiB

Open AccessArticle

Effect of Quenching Temperature on Microstructure and Hydrogen-Induced Cracking Susceptibility in S355 Steel

by Chunyan Yan, Shenglin Zhang, Lingchuan Zhou, Zhanpeng Tian, Mengdie Shen and Xinyi Liu

Materials 2025, 18(5), 1161; https://doi.org/10.3390/ma18051161 - 5 Mar 2025

Viewed by 577

Abstract

S355 steels are widely used in various applications. However, they may be affected by hydrogen, which can induce hydrogen-induced cracking (HIC). The effects of the quenching temperature (T_wq) on the microstructure variation and HIC susceptibility of S355 steel was investigated [...] Read more.

S355 steels are widely used in various applications. However, they may be affected by hydrogen, which can induce hydrogen-induced cracking (HIC). The effects of the quenching temperature (T_wq) on the microstructure variation and HIC susceptibility of S355 steel was investigated by microstructural characterization, hydrogen permeation (HP) test, slow strain rate tensile (SSRT) test, hydrogen microprint technique (HMT) test, and hydrogen-charged cracking test. The results indicate that the microstructure of the treated specimens consisted of predominantly lath martensite (LM) and small amounts of lath bainite (LB) for the T_wq of 950 °C and 1000 °C, while the microstructure of the treated specimens mainly consisted of LM for the T_wq of 1050 °C and 1100 °C. The results indicate that as the T_wq increased, the sample treated at 950 °C exhibited a minimum hydrogen embrittlement index (I_z), while the sample treated at 1050 °C exhibited the maximum I_z. The hydrogen diffusion coefficient was relatively low, while the hydrogen concentration and trap density were relatively high for the T_wq of 1050 °C. The lath interfaces in martensite were effective hydrogen traps with high hydrogen-trapping efficiency. Hydrogen-induced cracks were significantly affected by hydrogen trapping at martensitic lath interfaces, exhibiting a basically transgranular fracture. Full article

(This article belongs to the Special Issue Microstructure, Mechanical Properties and Wear Performance of High-Strength Steels)

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20 pages, 24972 KiB

Open AccessArticle

Study on the Preparation and Corrosion–Wear Properties of TiN/Sn Coatings on the Ti-25Nb-3Zr-2Sn-3Mo Titanium Alloy

by Jiang Pu, Yan Dai, Kunmao Li and Li Chen

Materials 2025, 18(5), 1160; https://doi.org/10.3390/ma18051160 - 5 Mar 2025

Viewed by 1890

Abstract

Due to its excellent specific strength, corrosion resistance, and biocompatibility, titanium alloy is often used as a biological implant material. In order to address the issues of low hardness and poor wear resistance of the Ti-25Nb-3Zr-2Sn-3Mo titanium alloy, a TiN/Sn coating with good [...] Read more.

Due to its excellent specific strength, corrosion resistance, and biocompatibility, titanium alloy is often used as a biological implant material. In order to address the issues of low hardness and poor wear resistance of the Ti-25Nb-3Zr-2Sn-3Mo titanium alloy, a TiN/Sn coating with good biocompatibility was deposited on its surface using a new composite modification technology of surface mechanical strengthening + surface mechanical coating. By taking advantage of the wear resistance of TiN and the adhesiveness of Sn, a composite coating with corrosion–wear resistance was formed to improve its corrosion–wear resistance. Using TiN/Sn powders of different ratios (10% Sn, 20% Sn, 30% Sn, and 40% Sn) as media, the alloy was subjected to a combined strengthening treatment of surface mechanical attrition and solid-phase coating under a nitrogen atmosphere. The microstructure and mechanical properties of the composite-strengthened layer were tested by means of XRD, SEM-EDS, a nanoindentation tester, a white-light interferometer, and a reciprocating wear tester. Moreover, the corrosion–wear properties of the samples under different loads and electrochemical conditions were analyzed. The results show that the surface composite-strengthened layer of the alloy consisted of a TiN/Sn coating + a mechanical deformed layer. With an increase in the Sn content, the thickness of the TiN/Sn coating continuously increased, while the thickness of the mechanical deformed layer continuously decreased. The composite-strengthened layer had good comprehensive mechanical properties. In the SBF solution, the corrosion–wear resistance of the composite-strengthened samples improved; the degree of wear first decreased and then increased with the increase in the Sn content, and it reached the optimal value when the Sn content was 30%. Compared with the raw sample, the corrosion of the coating sample increased, but the wear significantly decreased. The corrosion–wear synergy factor κ value first increased and then decreased with the increase in the Sn content, reaching a maximum value at the 20% Sn content. This is the result of the combined effect of the corrosion resistance and wear resistance of the coating. Full article

(This article belongs to the Special Issue Corrosion and Mechanical Behavior of Metal Materials (3rd Edition))

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18 pages, 7417 KiB

Open AccessArticle

An Efficient Optimization Method for Large-Solution Space Electromagnetic Automatic Design

by Lingyan He, Fengling Peng and Xing Chen

Materials 2025, 18(5), 1159; https://doi.org/10.3390/ma18051159 - 5 Mar 2025

Viewed by 484

Abstract

In the field of electromagnetic design, it is sometimes necessary to search for the optimal design solution (i.e., the optimal solution) within a large solution space to complete the optimization. However, traditional optimization methods are not only slow in searching for the solution [...] Read more.

In the field of electromagnetic design, it is sometimes necessary to search for the optimal design solution (i.e., the optimal solution) within a large solution space to complete the optimization. However, traditional optimization methods are not only slow in searching for the solution space but are also prone to becoming trapped in local optima, leading to optimization failure. This paper proposes a dual-population genetic algorithm to quickly find the optimal solution for electromagnetic optimization problems in large solution spaces. The method involves two populations: the first population uses the powerful dynamic decision-making ability of reinforcement learning to adjust the crossover probability, making the optimization process more stable and enhancing the global optimization capability of the algorithm. The second population accelerates the convergence speed of the algorithm by employing a “leader dominance” mechanism, allowing the population to quickly approach the optimal solution. The two populations are integrated through an immigration operator, improving optimization efficiency. The effectiveness of the proposed method is demonstrated through the optimization design of an electromagnetic metasurface material. Furthermore, the method designed in this paper is not limited to the electromagnetic field and has practical value in other engineering optimization areas, such as vehicle routing optimization, energy system optimization, and fluid dynamics optimization, etc. Full article

(This article belongs to the Special Issue Metamaterials and Metasurfaces: From Materials to Applications)

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14 pages, 4386 KiB

Open AccessArticle

Enhanced Cement Foam Composite with Biochar for Eriochrome Black T Dye Removal

by Mohammed Ettahar Boussalah, Malika Medjahdi, Sofiane Guella and Dominique Baillis

Materials 2025, 18(5), 1158; https://doi.org/10.3390/ma18051158 - 5 Mar 2025

Viewed by 616

Abstract

Cement-based foam composites have gained attention as innovative and high-performing adsorbents for wastewater treatment due to their lightweight, porous, and structurally robust properties. This study investigates the adsorption of Eriochrome Black T dye onto biochar-modified cement foam, providing a cost-effective solution for industrial [...] Read more.

Cement-based foam composites have gained attention as innovative and high-performing adsorbents for wastewater treatment due to their lightweight, porous, and structurally robust properties. This study investigates the adsorption of Eriochrome Black T dye onto biochar-modified cement foam, providing a cost-effective solution for industrial wastewater management. The integration of biochar into cement foam enhances its surface area and adsorption capabilities while maintaining structural stability and tunable porosity. The composites were characterized using scanning electron microscopy, Fourier-transform infrared spectroscopy, and energy-dispersive X-ray spectroscopy to verify quality and functionality. The adsorption process adhered to the Freundlich isotherm model (R² = 0.967), indicating multilayer adsorption, with a maximum capacity of 13.33 mg/g under optimal conditions. Kinetic studies showed a pseudo-first-order fit (R² = 0.981), while thermodynamic analysis revealed a spontaneous and endothermic process, with ΔH° = 28.84 KJ/mol and ΔG° values ranging from −0.457 to −2.36 KJ/mol. These results demonstrate the composite’s exceptional efficiency and scalability, making it a sustainable and practical option for removing persistent dyes such as Eriochrome Black T. This work contributes significantly to the advancement of environmentally friendly wastewater treatment technologies. Full article

(This article belongs to the Special Issue Recent Advances in the Environmental Remediation Using Zeolites and Other Adsorbent Materials)

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