Journal Description
Materials
Materials
is an international peer-reviewed, open access journal on materials science and engineering published semimonthly online by MDPI. The Portuguese Materials Society (SPM), Spanish Materials Society (SOCIEMAT) and Manufacturing Engineering Society (MES) are affiliated with Materials and their members receive discounts on the article processing charges.
- Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
- High Visibility: indexed within Scopus, SCIE (Web of Science), PubMed, PMC, Ei Compendex, CaPlus / SciFinder, Inspec, Astrophysics Data System, and other databases.
- Journal Rank: JCR - Q2 (Metallurgy & Metallurgical Engineering) / CiteScore - Q2 (Condensed Matter Physics)
- Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 13.9 days after submission; acceptance to publication is undertaken in 2.7 days (median values for papers published in this journal in the second half of 2023).
- Recognition of Reviewers: reviewers who provide timely, thorough peer-review reports receive vouchers entitling them to a discount on the APC of their next publication in any MDPI journal, in appreciation of the work done.
- Testimonials: See what our editors and authors say about Materials.
- Companion journals for Materials include: Electronic Materials and Construction Materials.
Impact Factor:
3.4 (2022);
5-Year Impact Factor:
3.8 (2022)
Latest Articles
Correction: Fang et al. Study on Dispersion, Adsorption, and Hydration Effects of Polycarboxylate Superplasticizers with Different Side Chain Structures in Reference Cement and Belite Cement. Materials 2023, 16, 4168
Materials 2024, 17(9), 2120; https://doi.org/10.3390/ma17092120 (registering DOI) - 30 Apr 2024
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Open AccessReview
Advances in Computational Methods for Modeling Photocatalytic Reactions: A Review of Recent Developments
by
Sergey Gusarov
Materials 2024, 17(9), 2119; https://doi.org/10.3390/ma17092119 (registering DOI) - 30 Apr 2024
Abstract
Photocatalysis is a fascinating process in which a photocatalyst plays a pivotal role in driving a chemical reaction when exposed to light. Its capacity to harness light energy triggers a cascade of reactions that lead to the formation of intermediate compounds, culminating in
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Photocatalysis is a fascinating process in which a photocatalyst plays a pivotal role in driving a chemical reaction when exposed to light. Its capacity to harness light energy triggers a cascade of reactions that lead to the formation of intermediate compounds, culminating in the desired final product(s). The essence of this process is the interaction between the photocatalyst’s excited state and its specific interactions with reactants, resulting in the creation of intermediates. The process’s appeal is further enhanced by its cyclic nature—the photocatalyst is rejuvenated after each cycle, ensuring ongoing and sustainable catalytic action. Nevertheless, comprehending the photocatalytic process through the modeling of photoactive materials and molecular devices demands advanced computational techniques founded on effective quantum chemistry methods, multiscale modeling, and machine learning. This review analyzes contemporary theoretical methods, spanning a range of lengths and accuracy scales, and assesses the strengths and limitations of these methods. It also explores the future challenges in modeling complex nano-photocatalysts, underscoring the necessity of integrating various methods hierarchically to optimize resource distribution across different scales. Additionally, the discussion includes the role of excited state chemistry, a crucial element in understanding photocatalysis.
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(This article belongs to the Special Issue Advanced Photocatalytic Material: Synthesis, Characterization and Application)
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Open AccessArticle
Tuning the Piezoelectric Performance of K0.5Na0.5NbO3 through Li Doping: Insights from Structural, Elastic and Electronic Analyses
by
Hui Li, Tianxiang Zhou, Kang Xu, Han Wang, Wenke Lu and Jinyi Liu
Materials 2024, 17(9), 2118; https://doi.org/10.3390/ma17092118 (registering DOI) - 30 Apr 2024
Abstract
The structural, elastic, piezoelectric, and electronic properties of Li-doped K0.5Na0.5NbO3 (K0.5−xNa0.5−yLix+yNbO3, KNN-L) are calculated. The properties of KNN-L are related to the Li-doping content and the
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The structural, elastic, piezoelectric, and electronic properties of Li-doped K0.5Na0.5NbO3 (K0.5−xNa0.5−yLix+yNbO3, KNN-L) are calculated. The properties of KNN-L are related to the Li-doping content and the replaced K or Na atoms. The bulk modulus, the shear modulus, and Young’s modulus of KNN-L are mostly higher than those of KNN, and the hardness value increases. The Poisson ratio of KNN-L is lower than that of most KNN, and the ductility is reduced. All doped structures are direct band gap semiconductors. K0.5Na0.375Li0.125NbO3 has the largest piezoelectric charge constant, d33 = 44.72 pC/N, in the respective structures, which is 1.5 fold that of K0.5Na0.5NbO3 (29.15 pC/N). The excellent piezoelectric performance of Li-doping KNN-L was analyzed from the insights of elastic and electronic properties.
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(This article belongs to the Section Materials Simulation and Design)
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Open AccessArticle
Mechanistic Study of Failure in CFRP Hybrid Bonded–Bolted Interference Connection Structures under Tensile Loading
by
Bin Luo, Liyang Xue, Qingsong Wang and Peng Zou
Materials 2024, 17(9), 2117; https://doi.org/10.3390/ma17092117 (registering DOI) - 30 Apr 2024
Abstract
Hybrid bonded–bolted composite material interference connections significantly enhance the collaborative load-bearing capabilities of the adhesive layer and bolts, thus improving structural load-carrying capacity and fatigue life. So, these connections offer significant developmental potential and application prospects in aircraft structural assembly. However, interference causes
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Hybrid bonded–bolted composite material interference connections significantly enhance the collaborative load-bearing capabilities of the adhesive layer and bolts, thus improving structural load-carrying capacity and fatigue life. So, these connections offer significant developmental potential and application prospects in aircraft structural assembly. However, interference causes damage to the adhesive layer and composite laminate around the holes, leading to issues with interface damage. In this study, we employed experimental and finite element methods. Initially, different interference-fit sizes were selected for bolt insertion to analyze the damage mechanism of the adhesive layer during interference-fit bolt installation. Subsequently, a finite element tensile model considering damage to the adhesive layer and composite laminate around the holes post-insertion was established. This study aimed to investigate damage in composite bonded–bolted hybrid joints, explore load-carrying rules and failure modes, and reveal the mechanisms of interference effects on structural damage and failure. The research results indicate that the finite element prediction model considering initial damage around the holes is more effective. As the interference-fit size increases, damage to the adhesive layer transitions from surface debonding to local cracking, while damage to the composite matrix shifts from slight compression failure to severe delamination and fiber-bending fracturing. The structural strength shows a trend of initially increasing and then decreasing, with the maximum strength observed at an interference-fit size of 1.1%.
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(This article belongs to the Section Advanced Composites)
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Microstructural Evolution, Hardness and Wear Resistance of WC-Co-Ni Composite Coatings Fabricated by Laser Cladding
by
Gibeom Kim, Yong-Chan Kim, Jae-Eock Cho, Chang-Hee Yim, Deok-Su Yun, Tae-Gyu Lee, Nam-Kyu Park, Rae-Hyung Chung and Dae-Geun Hong
Materials 2024, 17(9), 2116; https://doi.org/10.3390/ma17092116 (registering DOI) - 30 Apr 2024
Abstract
This study investigated how process parameters of laser cladding affect the microstructure and mechanical properties of WC-12Co composite coating for use as a protective layer of continuous caster rolls. WC-Co powders, WC-Ni powders, and Ni-Cr alloy powder with various wear resistance characteristics were
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This study investigated how process parameters of laser cladding affect the microstructure and mechanical properties of WC-12Co composite coating for use as a protective layer of continuous caster rolls. WC-Co powders, WC-Ni powders, and Ni-Cr alloy powder with various wear resistance characteristics were evaluated in order to determine their applicability for use as cladding materials for continuous caster roll coating. The cladding process was conducted with various parameters, including laser powers, cladding speeds, and powder feeding rates, then the phases, microstructure, and micro-hardness of the cladding layer were analyzed in each specimen. Results indicate that, to increase the hardness of the cladding layer in WC-Co composite coating, the dilution of the cladding layer by dissolution of Fe from the substrate should be minimized, and the formation of the Fe-Co alloy phase should be prevented. The mechanical properties and wear resistance of each powder with the same process parameters were compared and analyzed. The microstructure and mechanical properties of the laser cladding layer depend not only on the process parameters, but also on the powder characteristics, such as WC particle size and the type of binder material. Additionally, depending on the degree of thermal decomposition of WC particles and evolution of W distribution within the cladding layer, the hardness of each powder can differ significantly, and the wear mechanism can change.
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(This article belongs to the Section Thin Films and Interfaces)
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An Experimental Method to Capture the Thermal Conductivity Coefficient of Fine-Grained Concretes during Transition from Liquid to Solid
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Yannik Schwarz, Denis Ratke, David Sanio, Thomas Meurer and Peter Mark
Materials 2024, 17(9), 2115; https://doi.org/10.3390/ma17092115 (registering DOI) - 30 Apr 2024
Abstract
During the transition from liquid to solid, the thermal conductivity coefficient λ of concrete decreases. Although λ of hardened concrete is well investigated, there is limited research on the transition from liquid to solid and how it depends on hydration. Currently, only simplified
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During the transition from liquid to solid, the thermal conductivity coefficient λ of concrete decreases. Although λ of hardened concrete is well investigated, there is limited research on the transition from liquid to solid and how it depends on hydration. Currently, only simplified qualitative approaches exist for the liquid state and the transient process. An experimental method is not available. For this purpose, a test rig is designed to experimentally capture the evolution of λ for fine-grain concretes during transition. The performance of the test setup is evaluated on a characteristic high-performance concrete (HPC). The results are compared to theoretical predictions from the literature. The developed test rig is mapped in a digital twin to investigate extended boundary conditions, such as different heat sources and temperatures of the experimental setup. It allows the experiment to be repeated and optimized for different setups with little effort. The test principle is as follows: A liquid concrete sample is heated through a controlled external source, while the transient temperature distribution over the height is measured with a fiber optic sensor. The thermal conductivity is derived from the heat flux induced and the temperature distribution over an evaluation length. Experiments show that λ in the liquid state is approximately 1.4 times greater than in the solid state and exponentially decreases for the transient process. Numerical results on the digital twin indicate that the robustness of the results increases with the temperature of the heat source. Moreover, the derivation in λ turns out to be strongly dependent on the evaluation length. A length of three times the maximum grain diameter is recommended.
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(This article belongs to the Section Construction and Building Materials)
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Open AccessArticle
Thermo-Mechanical Optimization of Die Casting Molds Using Topology Optimization and Numerical Simulations
by
Serouj Djabraian, Fabian Teichmann and Sebastian Müller
Materials 2024, 17(9), 2114; https://doi.org/10.3390/ma17092114 (registering DOI) - 30 Apr 2024
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Conventional cooling channels used in die casting molds exhibit significant drawbacks, resulting in extended cooling times for cast parts. Issues such as the formation of dirt, limescale, and corrosion substantially diminish the thermal efficiency of these channels, leading to challenges in achieving uniform
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Conventional cooling channels used in die casting molds exhibit significant drawbacks, resulting in extended cooling times for cast parts. Issues such as the formation of dirt, limescale, and corrosion substantially diminish the thermal efficiency of these channels, leading to challenges in achieving uniform cooling and potential quality issues. In response to these challenges, this study proposes Topology Optimization as a novel approach. It involves designing cooling structures through Topology Optimization to replace traditional cooling channels, incorporating both Discrete and Gaussian boundary conditions to optimize thermal efficiency. Additionally, Structural Topology Optimization is employed to ensure structural integrity, preventing deformation or yielding under high loads during the die casting process. Numerical analysis revealed superior thermal performance compared to conventional channels, particularly when subjected to Discrete and Gaussian boundary conditions. Furthermore, the application of the latter establishes conformal cooling and minimizes temperature gradients in the casting, reducing casting defects such as shrinkage porosity. These findings highlight the efficacy of Topology Optimization in addressing the challenges of traditional cooling methods, with wide-ranging implications for manufacturing processes utilizing permanent molds for shaping materials.
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(This article belongs to the Special Issue Advanced Casting of Materials)
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Oriented Interpenetrating Capillary Network with Surface Engineering by Porous ZnO from Wood for Membrane Emulsification
by
Yaodong Chen, Xiaolin Liu, Gonggang Liu, Shanshan Chang and Jinbo Hu
Materials 2024, 17(9), 2113; https://doi.org/10.3390/ma17092113 - 30 Apr 2024
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Membrane emulsification technology has garnered increasing interest in emulsion preparation due to controllable droplet size, narrower droplet size distribution, low energy consumption, simple process design and excellent reproducibility. Nevertheless, the pore structure and surface engineering in membrane materials design play a crucial role
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Membrane emulsification technology has garnered increasing interest in emulsion preparation due to controllable droplet size, narrower droplet size distribution, low energy consumption, simple process design and excellent reproducibility. Nevertheless, the pore structure and surface engineering in membrane materials design play a crucial role in achieving high-quality emulsions with high throughput simultaneously. In this work, an oriented interpenetrating capillary network composed of highly aligned and interconnected wood cell lumens has been utilized to fabricate an emulsion membrane. A novel honeycomb porous ZnO layer obtained by a seed prefabrication–hydrothermal growth method was designed to reconstruct wood channel surfaces for enhanced microfluid mixing. The results show that through the unique capillary mesh microstructure of wood, the emulsion droplets were smaller in size, had narrower pore-size distribution, and were easy to obtain under high throughput conditions. Meanwhile, a well-designed ZnO layer could further improve the emulsion quality of a wood membrane, while the emulsifying throughput is still maintained at a higher level. This demonstrates that the convection process of the microfluid in these wood capillary channels was intensified markedly. This study not only develops advanced membrane materials in emulsion preparation, but also introduces a brand-new field for functional applications of wood.
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(This article belongs to the Special Issue High-Valued and New Utilizations of Biomass Material for Function Applications)
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Investigation of Mechanical Properties of Polymer-Infiltrated Tetrapodal Zinc Oxide in Different Variants
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Franziska Scherer, Sebastian Wille, Lena Saure, Fabian Schütt, Benjamin Wellhäußer, Rainer Adelung and Matthias Kern
Materials 2024, 17(9), 2112; https://doi.org/10.3390/ma17092112 - 29 Apr 2024
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The aim of this study was to evaluate the influence of weight ratio, the shape of the precursor particles, and the application of a phosphate-monomer-containing primer on the mechanical properties of polymer infiltrated ceramic networks (PICNs) using zinc oxide. Two different types of
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The aim of this study was to evaluate the influence of weight ratio, the shape of the precursor particles, and the application of a phosphate-monomer-containing primer on the mechanical properties of polymer infiltrated ceramic networks (PICNs) using zinc oxide. Two different types of zinc oxide particles were used as precursors to produce zinc oxide networks by sintering, each with two different densities resulting in two different weight ratios of the PICNs. For each of these different networks, two subgroups were built: one involving the application of a phosphate-monomer-containing primer prior to the infiltration of Bis-GMA/TEGDMA and one without. Elastic modulus and flexural strength were determined by using the three-point bending test. Vertical substance loss determined by the chewing simulation was evaluated with a laser scanning microscope. There was a statistically significant influence of the type of precursor particles on the flexural strength and in some cases on the elastic modulus. The application of a primer lead to a significant increase in the flexural strength and in most cases also in the elastic modulus. A higher weight ratio of zinc oxide led to a significantly higher elastic modulus. Few statistically significant differences were found for the vertical substance loss. By varying the shape of the particles and the weight fraction of zinc oxide, the mechanical properties of the investigated PICN can be controlled. The use of a phosphate-monomer-containing primer strengthens the bond between the infiltrated polymer and the zinc oxide, thus increasing the strength of the composite.
Full article
(This article belongs to the Special Issue Polymer Composites: Microstructural, Thermal and Mechanical Properties (Second Volume))
Open AccessArticle
Iron–Carbon Nanospheres as Promising Material for Magnetic Assisted Adsorption and Separation of Impurities from a Liquid Phase
by
Iwona Pełech, Sabina Lewinska, Monika Arciszewska, Abdul Khaliq, Anna Ślawska-Waniewska, Daniel Sibera, Piotr Staciwa and Urszula Narkiewicz
Materials 2024, 17(9), 2111; https://doi.org/10.3390/ma17092111 - 29 Apr 2024
Abstract
The composites containing various iron compounds and highly microporous carbon spheres were produced and investigated for structural and magnetic properties. Iron citrate, nitrate and chloride were used to prepare samples and the obtained products contained iron, iron carbide or magnetite. All the produced
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The composites containing various iron compounds and highly microporous carbon spheres were produced and investigated for structural and magnetic properties. Iron citrate, nitrate and chloride were used to prepare samples and the obtained products contained iron, iron carbide or magnetite. All the produced samples were characterized by high porosity and good magnetic properties. The coupling of the high porosity of carbon spheres with magnetic properties of iron compounds provides a potential application of the composites to removal of impurities from water, followed by a magnetic separation of the sorbent.
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(This article belongs to the Special Issue Adsorption Materials and Their Applications)
Open AccessArticle
Microstructural Evolution and Failure in Fibrous Network Materials: Failure Mode Transition from the Competition between Bond and Fiber
by
Yao Zhang, Weihua Wang, Pengfei Wang, Zixing Lu and Zhenyu Yang
Materials 2024, 17(9), 2110; https://doi.org/10.3390/ma17092110 - 29 Apr 2024
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For the complex structure of fibrous network materials, it is a challenge to analyze the network strength and deformation mechanism. Here, we identify a failure mode transition within the network material comprising brittle fibers and bonds, which is related to the strength ratio
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For the complex structure of fibrous network materials, it is a challenge to analyze the network strength and deformation mechanism. Here, we identify a failure mode transition within the network material comprising brittle fibers and bonds, which is related to the strength ratio of the bond to the fiber. A failure criterion for this type of fibrous network is proposed to quantitatively characterize this transition between bond damage and fiber damage. Additionally, tensile experiments on carbon and ceramic fibrous network materials were conducted, and the experimental results show that the failure modes of these network materials satisfy the theoretical prediction. The relationship between the failure mode, the relative density of network and strength of the components is established based on finite element analysis of the 3D network model. The failure mode transforms from bond damage to fiber damage as increasing of bond strength. According to the transition of the failure modes in the brittle fibrous network, it is possible to tailor the mechanical properties of fibrous network material by balancing the competition between bond and fiber properties, which is significant for optimizing material design and engineering applications.
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Open AccessArticle
Effect of Welding Parameters on Al/Mg Dissimilar Friction Stir Lap Welding with and without Ultrasonic Vibration
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Junjie Zhao, Bo Zhao, Chuansong Wu and Najib Ahmad Muhammad
Materials 2024, 17(9), 2109; https://doi.org/10.3390/ma17092109 - 29 Apr 2024
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The amount of heat input during welding impacts the weld’s thermal and mechanical behavior and the joint’s properties. The current study involved conducting AA 6061 and AZ31B Mg dissimilar welding, using friction stir lap welding (FSLW) and ultrasonic vibration-enhanced FSLW (UVeFSLW). The comparison
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The amount of heat input during welding impacts the weld’s thermal and mechanical behavior and the joint’s properties. The current study involved conducting AA 6061 and AZ31B Mg dissimilar welding, using friction stir lap welding (FSLW) and ultrasonic vibration-enhanced FSLW (UVeFSLW). The comparison and analysis of the welding load, the weld’s macro-microstructure, intermetallic compounds (IMCs), and joint properties were conducted by adjusting the process parameters. The study also examined the effect of ultrasonic vibration (UV) variations on welding heat input. The study demonstrated that it is possible to reduce the welding load by employing UV. Moreover, this impact becomes more pronounced as the welding heat input decreases. Additionally, the material flow in the weld, the width of the weld nugget zone, and the continuous IMC layer are significantly influenced by ultrasonic vibration, irrespective of the heat input during welding. However, the impact on large areas of irregular IMCs or eutectic structures is relatively small. Furthermore, achieving better joint properties becomes more feasible when a higher welding speed is employed for the Al alloy placed on top. Specifically, the impact of UV becomes more evident at higher welding speeds (≥220 mm/min).
Full article
(This article belongs to the Topic Development of Friction Stir Welding and Processing)
Open AccessArticle
Machine Learning-Based Simulation of the Air Conditioner Operating Time in Concrete Structures with Bayesian Thresholding
by
Changhwan Jang, Hong-Gi Kim and Byeong-Hun Woo
Materials 2024, 17(9), 2108; https://doi.org/10.3390/ma17092108 - 29 Apr 2024
Abstract
Efficient energy use is crucial for achieving carbon neutrality and reduction. As part of these efforts, research is being carried out to apply a phase change material (PCM) to a concrete structure together with an aggregate. In this study, an energy consumption simulation
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Efficient energy use is crucial for achieving carbon neutrality and reduction. As part of these efforts, research is being carried out to apply a phase change material (PCM) to a concrete structure together with an aggregate. In this study, an energy consumption simulation was performed using data from concrete mock-up structures. To perform the simulation, the threshold investigation was performed through the Bayesian approach. Furthermore, the spiking part of the spiking neural network was modularized and integrated into a recurrent neural network (RNN) to find accurate energy consumption. From the training-test results of the trained neural network, it was possible to predict data with an R2 value of 0.95 or higher through data prediction with high accuracy for the RNN. In addition, the spiked parts were obtained; it was found that PCM-containing concrete could consume 32% less energy than normal concrete. This result suggests that the use of PCM can be a key to reducing the energy consumption of concrete structures. Furthermore, the approach of this study is considered to be easily applicable in energy-related institutions and the like for predicting energy consumption during the summer.
Full article
(This article belongs to the Special Issue State-of-the-Art Construction Materials and Technologies for Structural Health Monitoring of Infrastructures)
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Open AccessCommunication
Load-Independent Hardness and Indentation Size Effect in Iron Aluminides
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Sebastian Balos, Milan Pecanac, Mirjana Trivkovic, Savo Bojic and Pavel Hanus
Materials 2024, 17(9), 2107; https://doi.org/10.3390/ma17092107 - 29 Apr 2024
Abstract
In this paper, an iron–aluminide intermetallic compound with cerium addition was subjected to Vickers microhardness testing. A full range of Vickers microhardness loadings was applied: 10, 25, 50, 100, 200, 300, 500, and 1000 g. Tests were conducted in two areas: 0.5 mm
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In this paper, an iron–aluminide intermetallic compound with cerium addition was subjected to Vickers microhardness testing. A full range of Vickers microhardness loadings was applied: 10, 25, 50, 100, 200, 300, 500, and 1000 g. Tests were conducted in two areas: 0.5 mm under the surface of the rolled specimen and in the center. The aim was to find the optimal loading range that gives the true material microhardness, also deemed load-independent hardness, HLIH. The results suggest that in the surface area, the reverse indentation size effect (RISE) occurred, similar to ceramics and brittle materials, while in the center, indentation size effect (ISE) behavior was obtained, more similar to metals. This clearly indicated an optimal microhardness of over 500 g in the surface region and over 100 g in the central region of the specimen. Load dependencies were quantitatively described by Meyer’s law, proportional specimen resistance (PSR), and the modified PSR model. The modified PSR model proved to be the most adequate.
Full article
(This article belongs to the Special Issue Intermetallics: From Design to Structural and Properties)
Open AccessArticle
Quasi-In Situ Observation of the Microstructural Response during Fatigue Crack Growth of Friction Stir Welded AA2024-T4 Joint
by
Jun Yang, Xianmin Chen, Huaxia Zhao, Jihong Dong and Feng Jin
Materials 2024, 17(9), 2106; https://doi.org/10.3390/ma17092106 - 29 Apr 2024
Abstract
The reliability of friction stir welded joints is a critical concern, particularly given their potential applications in the aerospace manufacturing industry. This study offers a quasi-in situ observation of the microstructural response during fatigue crack growth (FCG) of a friction stir welded AA2024-T4
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The reliability of friction stir welded joints is a critical concern, particularly given their potential applications in the aerospace manufacturing industry. This study offers a quasi-in situ observation of the microstructural response during fatigue crack growth (FCG) of a friction stir welded AA2024-T4 joint, aiming to correlate fatigue crack growth behavior with mechanical properties investigated using electron backscatter diffraction (EBSD). Notched compact tension (CT) specimens corresponding to the morphology of the stir zone (SZ), advancing side (AS), and retreating side (RS) were meticulously designed. The findings indicate that the welding process enhances the joint’s resistance to fatigue crack growth, with the base metal exhibiting a shorter fatigue life (i.e., ~105 cycles) compared to the welding zones (SZ ~ 3.5 × 105 cycles, AS ~ 2.5 × 105 cycles, and RS ~ 3.0 × 105 cycles). Crack propagation occurs within the stir zone, traversing refined grains, which primarily contribute to the highest fatigue life and lowest FCG rate. Additionally, cracks initiate in AS and RS, subsequently expanding into the base metal. Moreover, the study reveals a significant release of residual strain at the joint, particularly notable in the Structural-CT-RS (Str-CT-RS) sample compared to the Str-CT-AS sample during the FCG process. Consequently, the FCG rate of Str-CT-AS is higher than that of Str-CT-RS. These findings have significant implications for improving the reliability and performance of aerospace components.
Full article
(This article belongs to the Special Issue Advances in Solid-State Welding Processes)
Open AccessArticle
Synthesis of MPEG-b-PLLA Diblock Copolymers and Their Crystallization Performance with PDLA and PLLA Composite Films
by
Wenjing Wu, Weixin Wu, Mingwei Guo, Ruizhe Wang, Xuanxuan Wang and Qinwei Gao
Materials 2024, 17(9), 2105; https://doi.org/10.3390/ma17092105 - 29 Apr 2024
Abstract
Methoxy poly(ethylene glycol)-block-poly(L-lactide) (MPEG-b-PLLA) has a wide range of applications in pharmaceuticals and biology, and its structure and morphology have been thoroughly studied. In the experiment, we synthesized MPEG-b-PLLA with different block lengths using the principle of ring-opening polymerization by controlling the amount
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Methoxy poly(ethylene glycol)-block-poly(L-lactide) (MPEG-b-PLLA) has a wide range of applications in pharmaceuticals and biology, and its structure and morphology have been thoroughly studied. In the experiment, we synthesized MPEG-b-PLLA with different block lengths using the principle of ring-opening polymerization by controlling the amount of lactic acid added. The thermodynamic properties of copolymers and the crystallization properties of blends were studied separately. The crystallization kinetics of PDLA/MPEG-b-PLA and PLLA/MPEG-b-PLA composite films were studied using differential scanning calorimetry (DSC). The results indicate that the crystallization kinetics of composite films are closely related to the amount of block addition. The crystallinity of the sample first increases and then decreases with an increase in MPEG-b-PLLA content. These results were also confirmed in polarized optical microscope (POM) and wide-angle X-ray diffraction (WAXD) tests. When 3% MPEG-b-PLLA was added to the PDLA matrix, the blend exhibited the strongest crystallization performance.
Full article
Open AccessReview
Progress and Challenges of Additive Manufacturing of Tungsten and Alloys as Plasma-Facing Materials
by
Logan Howard, Gabriel D. Parker and Xiao-Ying Yu
Materials 2024, 17(9), 2104; https://doi.org/10.3390/ma17092104 (registering DOI) - 29 Apr 2024
Abstract
Tungsten (W) and W alloys are considered as primary candidates for plasma-facing components (PFCs) that must perform in severe environments in terms of temperature, neutron fluxes, plasma effects, and irradiation bombardment. These materials are notoriously difficult to produce using additive manufacturing (AM) methods
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Tungsten (W) and W alloys are considered as primary candidates for plasma-facing components (PFCs) that must perform in severe environments in terms of temperature, neutron fluxes, plasma effects, and irradiation bombardment. These materials are notoriously difficult to produce using additive manufacturing (AM) methods due to issues inherent to these techniques. The progress on applying AM techniques to W-based PFC applications is reviewed and the technical issues in selected manufacturing methods are discussed in this review. Specifically, we focus on the recent development and applications of laser powder bed fusion (LPBF), electron beam melting (EBM), and direct energy deposition (DED) in W materials due to their abilities to preserve the properties of W as potential PFCs. Additionally, the existing literature on irradiation effects on W and W alloys is surveyed, with possible solutions to those issues therein addressed. Finally, the gaps in possible future research on additively manufactured W are identified and outlined.
Full article
(This article belongs to the Special Issue Materials, Processing, and Post-treatment for Metal-Based Additive Manufacturing)
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Open AccessArticle
Catalytic Oxidation of Chlorobenzene over Amorphous Manganese-Chromium Catalysts Supported by UiO-66-Derived ZrOx
by
Pengfei Zhu, Qiaosen Yuan, Na Li, Zhaoxia Hu and Shouwen Chen
Materials 2024, 17(9), 2103; https://doi.org/10.3390/ma17092103 - 29 Apr 2024
Abstract
The development of efficient catalysts with longevity to remove chlorobenzene is challenging due to Cl poisoning. Herein, a series of Mn-Cr/ZrOx catalysts supported by Zr-based metal-organic framework (UiO-66)-derived ZrOx was prepared and investigated for chlorobenzene (CB) catalytic oxidation. MnCr/ZrOx-M
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The development of efficient catalysts with longevity to remove chlorobenzene is challenging due to Cl poisoning. Herein, a series of Mn-Cr/ZrOx catalysts supported by Zr-based metal-organic framework (UiO-66)-derived ZrOx was prepared and investigated for chlorobenzene (CB) catalytic oxidation. MnCr/ZrOx-M prepared via a wet impregnation method presented an amorphous structure, indicating the homogeneous dispersion of Cr and Mn, which improved acid and redox properties. 40Mn7Cr3/ZrOx-M exhibited the best catalytic activity for chlorobenzene oxidation with T90 of 293 ℃, which is mainly due to the strong interaction between manganese and chromium promoted by the large specific surface area of the ZrOx support. Furthermore, 40Mn7Cr3/ZrOx-M presented excellent stability for chlorobenzene oxidation.
Full article
Open AccessArticle
Effect of Recycled Fine Aggregates on the Mechanical and Drying Shrinkage Properties of Alkali-Activated Recycled Concrete
by
Ling Luo, Wu Yao and Gang Liao
Materials 2024, 17(9), 2102; https://doi.org/10.3390/ma17092102 - 29 Apr 2024
Abstract
In this paper, the workability, mechanical, ion leaching, and drying shrinkage properties of alkali-activated concrete with recycled coarse and fine aggregates were studied, and the pore structure and micro-morphology of different alkali-activated recycled aggregate concretes (AARACs) were characterized by using the mercury intrusion
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In this paper, the workability, mechanical, ion leaching, and drying shrinkage properties of alkali-activated concrete with recycled coarse and fine aggregates were studied, and the pore structure and micro-morphology of different alkali-activated recycled aggregate concretes (AARACs) were characterized by using the mercury intrusion method and scanning electron microscopy, respectively. The experimental results showed that with the increase in the replacement rate of the recycled fine aggregate (RFA), the flowability showed a decreasing trend. Adding a certain amount of RFA improves the mechanical properties of the AARAC. The compressive strength at a curing age of 28 days was 65.3 MPa with 70 wt% RFA replacement. When the replacement rate of the RFA was 100 wt%, the maximum splitting tensile strength (4.5 MPa) was obtained at a curing age of 7 days. However, the addition of the RFA had little effect on the flexural strength of the AARAC. As an extension of the curing age, the splitting tensile strength, flexural strength, tension-to-compression ratio, and flexure-to-compression ratio all showed an increasing trend at first and then a decreasing trend. At a curing age of 7 days, the tension-to-compression ratio and flexure-to-compression ratio were both high (except for those of R100), indicating that the ductility and toughness of the specimen were improved. The addition of the RFA increased the drying shrinkage of the AARAC. At a curing age of 120 days, compared to the specimen without the RFA, the drying shrinkage rate of the specimen with the addition of 70 wt% RFA increased by 34.15%. As the curing age increased, the microstructure of the reaction products became denser, but the proportion of large-diameter pores increased. This study evaluated the application of RFA in AARAC. The experimental results showed that the RFA-based AARAC had acceptable mechanical and durability properties.
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(This article belongs to the Special Issue Advances in Concrete and Binders for Sustainable Engineering)
Open AccessArticle
Assessment of Changes in Abrasive Wear Resistance of a Welded Joint of Low-Alloy Martensitic Steel Using Microabrasion Test
by
Krzysztof Ligier, Jerzy Napiórkowski and Magdalena Lemecha
Materials 2024, 17(9), 2101; https://doi.org/10.3390/ma17092101 - 29 Apr 2024
Abstract
Martensitic low-alloy steels are widely used in machine construction. Due to their declared weldability, arc welding is most often used to join elements made of this type of steel. However, the high temperature associated with welding causes unfavourable changes in the microstructure, resulting
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Martensitic low-alloy steels are widely used in machine construction. Due to their declared weldability, arc welding is most often used to join elements made of this type of steel. However, the high temperature associated with welding causes unfavourable changes in the microstructure, resulting in reduced abrasion resistance. Therefore, it is important to know the tribological properties of the welded joint. This article presents the results of a study on the abrasion wear resistance of a welded joint of an abrasion-resistant steel. This study tested a welded joint of an abrasive-resistant steel produced by the arc welding method. Wear testing of the welded joint was carried out under laboratory conditions by the ball-cratering method in the presence of abrasive slurry on the cross-section of the welded joint. Based on the test results, the change in the abrasive wear rate of the material as a function of the distance from the welded joint axis was determined. It was also found that the thermal processes accompanying welding caused structural changes that increased the wear rate index value. Adverse changes in the tribological properties of a welded material persist up to a distance of approx. 20 mm from the weld centre.
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(This article belongs to the Special Issue Welding, Joining and Additive Manufacturing: Experiments, Materials and Modelling)
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