Materials

20 pages, 2422 KiB

Open AccessArticle

Effect of Al₇Cu₂Fe Particles on the Anisotropic Mechanical Properties and Formability of Al-Zn-Mg-Cu-Based Alloy Sheets

by Jonggyu Jeon, Sangjun Lee, Jeheon Jeon, Maru Kang and Heon Kang

Materials 2024, 17(23), 5924; https://doi.org/10.3390/ma17235924 (registering DOI) - 3 Dec 2024

The presence of Al₇Cu₂Fe particles, formed due to Fe impurities in Al-Zn-Mg-Cu alloys, significantly impacts mechanical properties and formability, which is crucial for the use of these alloys in the automotive and aerospace industries. In this study, we prepared [...] Read more.

The presence of Al₇Cu₂Fe particles, formed due to Fe impurities in Al-Zn-Mg-Cu alloys, significantly impacts mechanical properties and formability, which is crucial for the use of these alloys in the automotive and aerospace industries. In this study, we prepared Al-Zn-Mg-Cu-based alloy sheets with large (LF), small (SF), and no (NF) Al₇Cu₂Fe particles to explore their effects on recrystallization and mechanical behavior. These sheets were fabricated using controlled cooling rates and subsequent thermo-mechanical processing. Fine dispersion of Al₇Cu₂Fe particles in the SF sheet led to a substantial reduction in grain size (16.5 μm) and an increase in yield strength (168.6 MPa), albeit with lower ductility (24.6%). In contrast, the NF sheet exhibited a lower yield strength (141.5 MPa) but superior ductility (35.8%) due to the absence of Al₇Cu₂Fe particles, which prevented premature fracture. The SF sheet demonstrated lower anisotropy in ductility due to the uniform recrystallized grain orientations, while the LF and NF sheets exhibited significant anisotropy in yield strength. These findings indicate that optimizing Al₇Cu₂Fe particle dispersion is key to balancing the strength, ductility, and anisotropy in Al-Zn-Mg-Cu alloys. Full article

30 pages, 5337 KiB

Open AccessArticle

The Effect of Recycled Geogrid Fibres on Asphalt Concrete Performance: A Case Study from Poland

by Grzegorz Mazurek, Przemysław Buczyński and Artur Kowalczyk

Materials 2024, 17(23), 5923; https://doi.org/10.3390/ma17235923 (registering DOI) - 3 Dec 2024

Abstract

This study articulates findings from research pertaining to the utilisation of recycled geogrid in asphalt concrete. The issue of contamination of reclaimed waste with geosynthetic materials persists as a significant concern that warrants attention. In Poland, the allowable quantity of geogrid contaminants within [...] Read more.

This study articulates findings from research pertaining to the utilisation of recycled geogrid in asphalt concrete. The issue of contamination of reclaimed waste with geosynthetic materials persists as a significant concern that warrants attention. In Poland, the allowable quantity of geogrid contaminants within the mineral–asphalt composition is 0.1% w/w. The preliminary evaluation of the validity of the research topic was conducted based on an analysis of correspondence and survey outcomes. The fundamental material research was executed employing elements of experimental design theory. The experimental domain considered two qualitative factors: the type of bituminous mixture for the binding layer (AC16W and AC22W) and the type of geogrid material (glass, carbon), in addition to two quantitative factors: the length of the recycled geogrid fibres ranging from 1 cm to 5 cm, and the quantity of recycled geogrid fibres varying from 0.2% to 1%. A generalised linear model was employed for the analysis, enabling the consideration of dependent qualitative factors in forecasting characteristics. The qualitative evaluation of the resultant solution was conducted using multi-criteria optimisation via the Harrington function. Consequently, recycled carbon mesh fibres demonstrated a notably positive impact, enhancing the material’s quality by 22%. Regarding glass mesh, the fibre content should not exceed 0.2% in the AC22W mixture, whereas it can be increased to 1% in the AC16W mixture. Comparing all evaluated mixtures, it was ascertained that surpassing the allowable contamination limit of 0.1% in geogrid form does not result in a significant reduction in the quality of asphalt concrete compared to the reference mix. Full article

(This article belongs to the Special Issue Recycling and Resource Utilization of Waste)

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14 pages, 9110 KiB

Open AccessArticle

Surface-Grinding-Induced Recrystallization and Metal Flow Causes Corrosion-Assisted Penetrating Attack of High-Mn–Low-CR Casting Steel in Humid Environments

by Jin Sung Park, Myeong Hun Kang and Sung Jin Kim

Materials 2024, 17(23), 5922; https://doi.org/10.3390/ma17235922 (registering DOI) - 3 Dec 2024

Abstract

This study examined the surface-grinding-induced microstructural modifications and corrosion attacks in a penetrating form of a high-Mn–low-Cr casting steel slab under humid environments. Various experimental and analytical findings from field-emission scanning electron microscopy, electron backscatter diffraction, transmission electron microscopy, and electrochemical analyses revealed [...] Read more.

This study examined the surface-grinding-induced microstructural modifications and corrosion attacks in a penetrating form of a high-Mn–low-Cr casting steel slab under humid environments. Various experimental and analytical findings from field-emission scanning electron microscopy, electron backscatter diffraction, transmission electron microscopy, and electrochemical analyses revealed that the abrasive grinding process led to the formation of a surface deformed region, comprising a recrystallized fine grain layer and multiple streamlines. Corrosion initially occurs preferentially along the boundary areas where Cr(Mn)₂₃C₆ particles are precipitated. Moreover, the corrosion products (Fe-based oxy/hydroxides) with a high volumetric expansion ratio detach readily from the surface deformed regions, facilitating the easy penetration of corrosive media. In contrast to conventional low-alloyed steels, which exhibit uniform corrosion behavior, corrosion-assisted penetrating attacks on ground high-Mn–low-Cr casting steel slabs occur more severely and frequently during the summer/dry season (i.e., relative humidity levels around 60% to 80%, rather than 100%) when a thin water film can form on the steel surface. Based on the result, effective technical strategies in terms of metallurgical and environmental aspects to mitigate the risk of corrosion-assisted penetrating attack of high-Mn–low-Cr casting steel were discussed. Full article

(This article belongs to the Special Issue Recent Progress in Corrosion Protection and Electrochemical Characterization of New and Advanced Materials)

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16 pages, 10619 KiB

Open AccessArticle

The Role of the Bactericidal Mechanism of Copper Elements and Its Effect on the Corrosion Resistance of Steel

by Yunsheng Xue, Cheng Ding, Li Gong, Yingxue Teng, Jing Guo and Shanshan Chen

Materials 2024, 17(23), 5921; https://doi.org/10.3390/ma17235921 (registering DOI) - 3 Dec 2024

Abstract

In this paper, two kinds of copper-containing steels with copper contents of 2.31 and 6.01 wt.% were designed. By comparing with commercial Q355, the bactericidal properties of copper in seawater containing sulfate-reducing bacteria (SRB) and its influence on the corrosion process of steel [...] Read more.

In this paper, two kinds of copper-containing steels with copper contents of 2.31 and 6.01 wt.% were designed. By comparing with commercial Q355, the bactericidal properties of copper in seawater containing sulfate-reducing bacteria (SRB) and its influence on the corrosion process of steel were revealed. The corrosion rate, morphology of products, and bactericidal action of copper were tracked by scanning electron microscopy, X-ray diffraction, confocal microscopy, and electrochemical analysis techniques. It was found that the resistance of copper-containing steel to bacterial corrosion was obviously better than that of non-copper-containing steel. At 28 days, the weight loss rates in the SRB environment for 0Ni2Cu6 samples increased by merely 5.43%, which was nearly half that of Q355 of 9.75%. Cu-containing steels exhibited potent antibacterial action, with the ε-Cu phase altering the corrosion byproduct composition from brittle flakes to robust particles and inhibiting the production of H₂S. The killed bacteria adhered to the surface of the steel and slowed down the corrosion of the steel. The confocal laser scanning microscope and electrochemical experiments showed that a dense CuFeO₄ film formed on the substrate, impeding corrosive ion penetration, and an upsurge in Cu content markedly enhanced the material’s anti-corrosion and antimicrobial attributes. Full article

(This article belongs to the Special Issue Antibacterial and Corrosion-Resistant Coatings for Marine Application)

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14 pages, 1337 KiB

Open AccessArticle

Analysis of Liquid Sweat Transport in Underwear Combined with Multilayer Fabric Assemblies for Firefighter Outfits

by Małgorzata Matusiak and Otgonsuren Sukhbat

Materials 2024, 17(23), 5920; https://doi.org/10.3390/ma17235920 (registering DOI) - 3 Dec 2024

Abstract

A firefighter’s outfit consists of several layers with distinct properties and functions. These layers serve as barriers against external hazards but also impede the transport of sweat generated by the human body. As a result, sweat vapor often fails to transfer effectively from [...] Read more.

A firefighter’s outfit consists of several layers with distinct properties and functions. These layers serve as barriers against external hazards but also impede the transport of sweat generated by the human body. As a result, sweat vapor often fails to transfer effectively from the body through the firefighter’s protective clothing (FPC) to the environment. This can lead to sweat condensation on the firefighter’s skin, causing discomfort. To enhance the physiological comfort of firefighters during firefighting and other rescue operations, it is essential to consider the transport of condensed sweat within the multilayer textile system comprising both the underwear and the FPC. In this study, 16 assembly variants were tested, combining four types of knitted fabrics for underwear with four types of multilayer textile sets designed for FPC. The liquid moisture transport properties of these assemblies were evaluated using the Moisture Management Tester (MMT290), an innovative instrument manufactured by SDL Atlas. The results demonstrated that the knitted fabrics effectively transport liquid sweat, whereas in the case of multilayer textile sets for FPC, liquid sweat transport is primarily confined to the inner layer adjacent to the skin. Furthermore, the findings indicate that by selecting an appropriate combination of knitted fabric for underwear and the inner layer of the FPC, it is possible to optimize liquid moisture transport in a firefighter’s outfit. Full article

(This article belongs to the Special Issue Properties and Applications of Advanced Textile Materials)

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20 pages, 7757 KiB

Open AccessArticle

Behavior of Weathering Steel in Artificial Harsh Environment

by Tomasz Wierzbicki, Gabriela Rutkowska, Mariusz Żółtowski and Mykola Nagirniak

Materials 2024, 17(23), 5919; https://doi.org/10.3390/ma17235919 (registering DOI) - 3 Dec 2024

Abstract

The safety and durability of engineering structures, like bridges, which are designed from weathering steels, are conditioned by the development of a sufficiently protective layer of corrosion products. Air pollution, the microclimate around the bridge, the time of wetness, the structural solution of [...] Read more.

The safety and durability of engineering structures, like bridges, which are designed from weathering steels, are conditioned by the development of a sufficiently protective layer of corrosion products. Air pollution, the microclimate around the bridge, the time of wetness, the structural solution of the bridge, and the position and orientation of the surface within the bridge structure all influence the development of protective layers on the surface of the weathering steel. The condition of the formed patina relies on the working conditions of the structure. In fact, it is exposed to various types of salts that appear during the operation of the facility. In this article, the strength parameters of uncoated weathering steel were tested after accelerated aging of welded steel samples in a salt spray chamber. The tests showed the expected degradation of steel after long-term exposure to salt and changes in the strength parameters such as tensile strength, yield strength, and, importantly, impact strength, both in the steel itself and in the elements of the welded connection. The obtained results showed that the change is influenced by both the conditions in which the samples are made (welding method) and the direction of the welded joint (along or across the rolling direction). Full article

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

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27 pages, 5067 KiB

Open AccessReview

Materials Nanoarchitectonics for Advanced Devices

by Katsuhiko Ariga

Materials 2024, 17(23), 5918; https://doi.org/10.3390/ma17235918 (registering DOI) - 3 Dec 2024

Abstract

Advances in nanotechnology have made it possible to observe and evaluate structures down to the atomic and molecular level. The next step in the development of functional materials is to apply the knowledge of nanotechnology to materials sciences. This is the role of [...] Read more.

Advances in nanotechnology have made it possible to observe and evaluate structures down to the atomic and molecular level. The next step in the development of functional materials is to apply the knowledge of nanotechnology to materials sciences. This is the role of nanoarchitectonics, which is a concept of post-nanotechnology. Nanoarchitectonics is defined as a methodology to create functional materials using nanounits such as atoms, molecules, and nanomaterials as building blocks. Nanoarchitectonics is very general and is not limited to materials or applications, and thus nanoarchitecture is applied in many fields. In particular, in the evolution from nanotechnology to nanoarchitecture, it is useful to consider the contribution of nanoarchitecture in device applications. There may be a solution to the widely recognized problem of integrating top-down and bottom-up approaches in the design of functional systems. With this in mind, this review discusses examples of nanoarchitectonics in developments of advanced devices. Some recent examples are introduced through broadly dividing them into organic molecular nanoarchitectonics and inorganic materials nanoarchitectonics. Examples of organic molecular nanoarchitecture include a variety of control structural elements, such as π-conjugated structures, chemical structures of complex ligands, steric hindrance effects, molecular stacking, isomerization and color changes due to external stimuli, selective control of redox reactions, and doping control of organic semiconductors by electron transfer reactions. Supramolecular chemical processes such as association and intercalation of organic molecules are also important in controlling device properties. The nanoarchitectonics of inorganic materials often allows for control of size, dimension, and shape, and their associated physical properties can also be controlled. In addition, there are specific groups of materials that are suitable for practical use, such as nanoparticles and graphene. Therefore, nanoarchitecture of inorganic materials also has a more practical aspect. Based on these aspects, this review finally considers the future of materials nanoarchitectonics for further advanced devices. Full article

(This article belongs to the Section Materials Chemistry)

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42 pages, 1039 KiB

Open AccessReview

Progress in Additive Manufacturing of High-Entropy Alloys

by Bin Chen

Materials 2024, 17(23), 5917; https://doi.org/10.3390/ma17235917 (registering DOI) - 3 Dec 2024

Abstract

High-entropy alloys (HEAs) have drawn substantial attention on account of their outstanding properties. Additive manufacturing (AM), which has emerged as a successful approach for fabricating metallic materials, allows for the production of complex components based on three-dimensional (3D) computer-aided design (CAD) models. This [...] Read more.

High-entropy alloys (HEAs) have drawn substantial attention on account of their outstanding properties. Additive manufacturing (AM), which has emerged as a successful approach for fabricating metallic materials, allows for the production of complex components based on three-dimensional (3D) computer-aided design (CAD) models. This paper reviews the advancements in the AM of HEAs, encompassing a variety of AM techniques, including selective laser melting (SLM), selective laser sintering (SLS), selective electron beam melting (SEBM), directed energy deposition (DED), binder jetting (BJT), direct ink writing (DIW), and additive friction stir deposition (AFSD). Additionally, the study discusses the powders and wires utilized in AM, the post-processing of AM-processed HEAs, as well as the mechanical and corrosion properties of these alloys. The unique ultra-fine and non-equilibrium microstructures achieved through AM result in superior mechanical properties of HEAs, like improved strength and ductility. However, research regarding certain aspects of HEA AM, such as fatigue properties and creep deformation behavior, is still relatively scarce. Future research should focus on overcoming the existing limitations and exploring the potential of HEAs in various applications. Full article

(This article belongs to the Special Issue Advances in Multicomponent Alloy Design, Simulation and Properties)

12 pages, 2802 KiB

Open AccessArticle

Statistical Methods in the Analysis of the Effect of Carbonisate on the Hardness of Epoxy-Resin-Based Composites

by Agata Wieczorska and Sebastian Drewing

Materials 2024, 17(23), 5916; https://doi.org/10.3390/ma17235916 (registering DOI) - 3 Dec 2024

Abstract

This research concerns the manufacture and characterisation of epoxy composites with the addition of carbonisate, obtained by the pyrolysis of MDF (medium-density fibreboard) furniture board waste. The laminated composites were made by hand lamination, with the carbonisate used as a filler to improve [...] Read more.

This research concerns the manufacture and characterisation of epoxy composites with the addition of carbonisate, obtained by the pyrolysis of MDF (medium-density fibreboard) furniture board waste. The laminated composites were made by hand lamination, with the carbonisate used as a filler to improve the mechanical properties of the composite. The carbonisate was obtained by the thermal decomposition of MDF waste in an anaerobic environment by pyrolysis, which is an efficient method of waste management and material recycling. The resulting carbonisate was integrated into an epoxy resin matrix to investigate its potential as a reinforcing agent. The article describes a study on the hardness of epoxy-resin-based composites to which carbonisate was added in different fractions and percentages. The aim of the research was to test the possibility of using char as a component in improving the mechanical properties of epoxy composites with a view towards creating a durable recycled material with optimal parameters. As part of the study, a statistical analysis of the results of hardness measurements was carried out to accurately assess the effect of the quantity and size of the carbonate particles on the mechanical properties of the materials. The analysis identified significant differences between samples and verified the repeatability of the results. It was found that the addition of carbonisate to the A0 base sample (without the addition of carbonisate) leads to a significant hardening of the material. This was confirmed by the higher medians of samples A01 (carbonisate 5% with a 0.5 mm fraction), A02 (carbonisate 7.5% with a 0.5 mm fraction), and A03 (carbonisate 5% with a 1.0 mm fraction) compared to the base sample. The most homogeneous hardness was shown in sample A02, with the highest concentration of results and the lowest values of standard deviation and spread. The results indicated that the addition of carbonate significantly increased the hardness of the composite materials, with optimal stability achieved at 7.5% (by weight) of carbonate with a 0.5 mm fraction. The conducted research precisely determined the influence of the amount and characteristics of carbonisate particles on the mechanical properties of the materials, which enables the more effective designing of future composites. The statistical results provide a reliable basis for evaluating the potential applications of these materials in various industrial sectors, such as construction, automotive and aerospace, where high hardness and durability are important. Full article

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15 pages, 2266 KiB

Open AccessArticle

Optimizing Cement Content in Controlled Low-Strength Soils: Effects of Water Content and Hydration Time

by Yilian Luo, Liangwei Jiang, Libing Qin, Qiang Luo, David P. Connolly and Tengfei Wang

Materials 2024, 17(23), 5915; https://doi.org/10.3390/ma17235915 (registering DOI) - 3 Dec 2024

Abstract

The Ethylene Diamine Tetra-acetic Acid (EDTA) titration test is widely used for determining cement content, but its reliability is influenced by the hydration process of cement, which is affected by factors such as water content and hydration time. Despite their importance, these factors [...] Read more.

The Ethylene Diamine Tetra-acetic Acid (EDTA) titration test is widely used for determining cement content, but its reliability is influenced by the hydration process of cement, which is affected by factors such as water content and hydration time. Despite their importance, these factors have received limited attention in existing research. This study explores the relationships between the volume of titrant required for stabilization, cement content, water content, and hydration time. Using a regression orthogonal test, the primary and secondary relationships, as well as the interdependencies among these factors, are analyzed. Results reveal a negative linear relationship between the titrant volume and both water content and hydration time. Cement content, water content, and hydration time are identified as the most significant factors, with minimal interdependencies observed. Within the test parameters, calculated values exhibit an error margin below 2.4%. Deviations of 2.9% in water content and 86 min in hydration time correspond to an approximate 0.5% change in cement content. These findings offer valuable insights for optimizing cement content detection in Controlled Low-Strength Material (CLSM) mixes, promoting more sustainable construction practices. Full article

(This article belongs to the Special Issue Sustainable Pavement Materials: Design, Application and Performance Evaluation)

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13 pages, 7782 KiB

Open AccessArticle

The Effect of p-Toluenesulfonic Acid and Phosphoric Acid (V) Content on the Heat Resistance and Thermal Properties of Phenol Resin and Phenol-Carbon Composite

by Łukasz Rybakiewicz and Janusz Zmywaczyk

Materials 2024, 17(23), 5914; https://doi.org/10.3390/ma17235914 (registering DOI) - 3 Dec 2024

Abstract

This work presents the results of research on the influence of the amount of p-toluenesulfonic acid and phosphoric acid (V) added to the phenol-formaldehyde resin (pH 7.3–7.8) on its thermal properties and on the phenol-formaldehyde-carbon composite produced on its basis. This material undergoes [...] Read more.

This work presents the results of research on the influence of the amount of p-toluenesulfonic acid and phosphoric acid (V) added to the phenol-formaldehyde resin (pH 7.3–7.8) on its thermal properties and on the phenol-formaldehyde-carbon composite produced on its basis. This material undergoes pyrolysis under high temperature. The addition of a catalyst to the phenol-formaldehyde resin affects its curing rate and degree of cross-linking, but how it affects the thermal properties of the resin depending on the temperature is the subject of this work. This article presents the results of thermal tests for phenol-formaldehyde resin and phenol-formaldehyde-carbon composite. It was examined how the content of the catalyst used during the production process affects the individual thermal parameters of the mentioned materials. The results include experimental tests of thermal diffusivity with uncertainty (±3%), specific heat capacity (±2.5%), thermal expansion with resolution 2 nm analyzed in the temperature range −40–115 °C and thermogravimetric TG/DTA analysis with resolution 0.03 µg in the temperature range from room temperature (RT = 23 °C) to 550 °C. Individual thermal tests showed changes in the thermal properties caused by changes in the catalyst content of the tested materials and the influence of the addition of carbon fibers on the properties of the composite compared to the pure phenol-formaldehyde resin. It was found that there is a certain maximum level of catalyst weight fraction at which the greatest decrease in thermal diffusivity occurs. In the case of phenolic-formaldehyde-carbon composite at −40 °C, an increase in catalyst weight fraction from 2 to 4 wt% caused a decrease in thermal diffusivity by 18.2%, and for phenol-formaldehyde resin, it was 2.8% with an increase in catalyst fraction from 4 to 10 wt%. Full article

(This article belongs to the Special Issue Advanced Composites: From Material Characterization to Structural Application (Third Edition))

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14 pages, 5593 KiB

Open AccessArticle

Influence of Selected Factors of Vibratory Work Hardening Machining on the Properties of CuZn30 Brass

by Damian Bańkowski, Anna Kiljan, Irena M. Hlaváčová and Piotr Młynarczyk

Materials 2024, 17(23), 5913; https://doi.org/10.3390/ma17235913 (registering DOI) - 3 Dec 2024

Abstract

The purpose of this study was to determine the effect of selected vibratory strengthening machining factors on the properties of CuZn30 brass. Vibratory strengthening machining was carried out using metal media dedicated to polishing processes, which also contributed to strengthening the treated surfaces. [...] Read more.

The purpose of this study was to determine the effect of selected vibratory strengthening machining factors on the properties of CuZn30 brass. Vibratory strengthening machining was carried out using metal media dedicated to polishing processes, which also contributed to strengthening the treated surfaces. The test samples were cut with an abrasive water jet and recrystallized to obtain a soft microstructure. An orthogonal, two-factor five-level plan was used for the study. The effect of vibration frequency and vibratory machining time on selected changes in parameters of the geometric structure of the surface and hardness of the surface layer was determined using Statistica software version 10 (64-bit). Higher vibration frequencies for vibratory machining increased the hardness of machined surfaces by as much as 50 HV_0.02. The arithmetic mean deviation of the height of surface irregularities from the reference plane, Sa, decreases with increasing the time of vibratory machining. A value of Sa = 0.168 µm was obtained after 87 min of consolidation, compared to an initial surface of S_a = 0.65 µm. Full article

(This article belongs to the Special Issue Material Surface Topography Measurement, Analysis and Characterization)

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22 pages, 6412 KiB

Open AccessArticle

Numerical Analysis and Theoretical Study on the Interfacial Bonding Behavior of High-Strength Steel Stainless Wire Mesh-Reinforced ECC and Concrete

by Chao Li, Yao Zou, Ziyuan Li, Xuyan Zou, Ke Li, Juntao Zhu, Hongbo Xiao and Jianwei Fan

Materials 2024, 17(23), 5912; https://doi.org/10.3390/ma17235912 (registering DOI) - 3 Dec 2024

Abstract

In order to investigate the interfacial bonding properties of high-strength steel stainless wire mesh-reinforced ECC (HSSWM-ECC) and concrete, a finite element model was established for two types of interfaces based on experimental research. The results show that the failure modes observed in the [...] Read more.

In order to investigate the interfacial bonding properties of high-strength steel stainless wire mesh-reinforced ECC (HSSWM-ECC) and concrete, a finite element model was established for two types of interfaces based on experimental research. The results show that the failure modes observed in the 21 groups of simulations can be classified into three categories: debonding failure, ECC extrusion failure and concrete splitting failure. The failure mode was mainly affected by the type of interface. The effective anchorage length is inversely proportional to the strength of the concrete and proportional to the stiffness and thickness of the HSSWM-ECC. The capacity of the roughening interface is positively correlated with the concrete strength and bonding length, but negatively correlated with the interfacial width ratio. Increasing both the number and width of grooves within the effective range enhances the interfacial capacity, whereas higher concrete strengths tend to reduce it. Based on the above results, calculation models for the effective anchorage length and bearing capacity were established separately for the two types of interfaces. The theoretical model for the interfacial bonding property between HSSWM-ECC and concrete has been refined. These advancements establish a theoretical groundwork for the design of concrete structures strengthened with HSSWM-ECC. Full article

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

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21 pages, 39456 KiB

Open AccessArticle

Surface Roughening Behavior and Mechanism in Aluminum Alloy Under Tensile Deformation

by Xiang Zeng, Shaoming Xu, Zhongbao Mi, Leheng Huang, Xuefeng Xu, Yubin Fan, Jiawen Yu, Xiaoguang Fan, Xiaoxiao Chen and Qiqi Tu

Materials 2024, 17(23), 5911; https://doi.org/10.3390/ma17235911 (registering DOI) - 3 Dec 2024

Abstract

Surface roughening (SR) has been found to occur in solid solution 2219 aluminum alloy under tensile deformation, which will deteriorate its surface quality. To make a precise study of the surface roughening (SR) behavior and mechanism, the surface morphology of annealed and solid [...] Read more.

Surface roughening (SR) has been found to occur in solid solution 2219 aluminum alloy under tensile deformation, which will deteriorate its surface quality. To make a precise study of the surface roughening (SR) behavior and mechanism, the surface morphology of annealed and solid solution 2219 aluminum alloy was compared and crystal plasticity finite element (CPFE) simulation was carried out in this study. Thereinto, representative volume element (RVE) models of polycrystals were established according to the initial grain morphology measured by electron backscatter diffraction (EBSD). The results show that the surface roughening degree of the solid solution specimen is worse than that of annealed specimen after uniaxial tension deformation. In comparison with the annealed specimen, the grains show a larger size after solid solution treatment, thus resulting in the coarse surface to a certain extent. Moreover, texture type and density also have a significant influence on surface roughness. The rotation of grains with an S and Copper orientation intensifies the surface roughening during tensile deformation. The deformation difficulty of Goss texture in the normal direction (ND) and tangential direction (TD) varies, thus contributing to the different surface morphology. The research results will provide guidance for the improvement of the surface quality of high-strength aluminum alloy aerospace components. Full article

(This article belongs to the Special Issue Recent Advances in Precision Manufacturing Technology)

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22 pages, 6271 KiB

Open AccessArticle

Evaluating the Impact of Sample Irregularities on the Dynamic Stiffness of Polyurethane: Insights from Experimental and FEM Analysis

by Krzysztof Nering, Arkadiusz Kwiecień and Konrad Nering

Materials 2024, 17(23), 5910; https://doi.org/10.3390/ma17235910 (registering DOI) - 3 Dec 2024

Abstract

This study investigates the dynamic stiffness and damping characteristics of three polyurethane materials—PM, PS, and PST—using a comprehensive vibroacoustic testing approach. The aim is to examine material parameters such as dynamic stiffness, Young’s modulus, critical damping factor, and the influence of sample irregularities [...] Read more.

This study investigates the dynamic stiffness and damping characteristics of three polyurethane materials—PM, PS, and PST—using a comprehensive vibroacoustic testing approach. The aim is to examine material parameters such as dynamic stiffness, Young’s modulus, critical damping factor, and the influence of sample irregularities on the accuracy of measurements. The study employs both experimental testing, in which cuboidal and cylindrical polyurethane samples were subjected to sinusoidal excitation, and finite element modeling (FEM) to simulate the test conditions in sample without irregularities. Results indicate that sample contact surface irregularities (even as low as ~0.04 mm) significantly impact the measured dynamic stiffness, with the effect intensifying for materials with higher Young’s modulus values (above 5 MPa). Furthermore, cylindrical samples demonstrated more stable and repeatable measurements compared to cuboidal samples, where surface irregularities were tested in a more controlled environment. The findings underscore the need to consider sample geometry and irregularities in dynamic stiffness assessments to ensure better material evaluations. This work contributes valuable insights for the accurate modeling and testing of materials used in vibration isolation and sound insulation contexts. Full article

(This article belongs to the Special Issue Research on Properties of Polymers and Their Engineering Applications)

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31 pages, 4224 KiB

Open AccessReview

Photovoltaic Cells and Scintillators Towards Carbon Footprint Reduction: Advantages and Challenges for Ecological Safety

by Agnieszka Iwan, Krzysztof A. Bogdanowicz, Robert Pich, Agnieszka Gonciarz, Witalis Pellowski, Jacek Miedziak and Wojciech Przybyl

Materials 2024, 17(23), 5909; https://doi.org/10.3390/ma17235909 (registering DOI) - 3 Dec 2024

Abstract

The main goal of this review paper is to show the advantages and challenges of photovoltaic cells/modules/panels and scintillators towards carbon footprint reduction for ecological safety. Briefly, the various types of solar-driven CO₂ conversion processes are shown as a new concept of [...] Read more.

The main goal of this review paper is to show the advantages and challenges of photovoltaic cells/modules/panels and scintillators towards carbon footprint reduction for ecological safety. Briefly, the various types of solar-driven CO₂ conversion processes are shown as a new concept of CO₂ reduction. The health toxicity and environmental effects of scintillators, along with risks associated with use and disposal, are presented, taking into consideration inorganic and organic materials. Factors affecting the durability and lifespan of scintillators and the carbon footprint of solar cell production are analysed, considering CO₂ emission. Moreover, the technology of recycling photovoltaic modules and scintillators, along with a SWOT analysis of scintillation material toxicity, is presented to find the best solutions for clean technology and ecological safety. Finally, we offer recommendations for the areas where the most significant reductions in CO₂ emissions are expected to be implemented in the future of green energy in industry, including ESG strategies. Full article

(This article belongs to the Special Issue Advanced Materials in Photoelectrics and Photonics)

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Graphical representation of toxicity and their main sources for all four solar cell generations [<a href="#B4-materials-17-05909" class="html-bibr">4</a>,<a href="#B5-materials-17-05909" class="html-bibr">5</a>,<a href="#B6-materials-17-05909" class="html-bibr">6</a>,<a href="#B7-materials-17-05909" class="html-bibr">7</a>]. Full article ">Figure 2
(a) The idea of converting radiation into photons of light. (b) There are three or two phases: the three-phase context involves generation and thermalisation (10−12–10−11 s), transport and movement of charges, and photon emission (10−9–10−6 s); the two-phase context involves generation and thermalisation and photon emission. The figure is an elaboration by this study’s authors, based on [<a href="#B13-materials-17-05909" class="html-bibr">13</a>]. Full article ">Figure 3
Chemical structure of polystyrene, polyvinyl toluene, and anthracene. Full article ">Figure 4
Schematic of types of solar-driven CO2 conversion. Own elaboration based on [<a href="#B73-materials-17-05909" class="html-bibr">73</a>]. Full article ">Figure 5
Chemical structure of EVA. Full article ">Figure 6
Carbon footprint for PV modules considering cell type and place of manufacture (EU/China). * modules produced and installed in the EU, # modules produced and installed in China. This figure is an elaboration by this study’s authors based on [<a href="#B82-materials-17-05909" class="html-bibr">82</a>]. Full article ">Figure 7
Comparison of the structure of glass–backsheet (G–B) module (a) and glass–glass (G–G) module (b). Full article ">

19 pages, 13917 KiB

Open AccessArticle

Investigation of Mechanical Properties and Color Changes of 3D-Printed Parts with Different Infill Ratios and Colors After Aging

by Oğuz Koçar, Nergizhan Anaç, Erhan Baysal, Furkan Parmaksız and İrfan Akgül

Materials 2024, 17(23), 5908; https://doi.org/10.3390/ma17235908 (registering DOI) - 3 Dec 2024

Abstract

Since their inception, plastics have become indispensable materials. However, plastics used for extended periods in industrial applications are prone to aging, which negatively impacts their material behavior and performance. To ensure the long-term usability of these materials, they must be tested in real-time, [...] Read more.

Since their inception, plastics have become indispensable materials. However, plastics used for extended periods in industrial applications are prone to aging, which negatively impacts their material behavior and performance. To ensure the long-term usability of these materials, they must be tested in real-time, in-service environments to assess degradation. In practice, however, accelerated aging techniques are commonly employed to avoid time loss. Over time, various indicators of degradation in plastics emerge, such as changes in molecular weight, cracking, and mechanical properties like strain at break and impact strength. Among these, color deterioration or change is a critical factor that helps evaluate the service life of these materials. Considering the increasing use of plastics in 3D printing today, and the growing focus on strength over aesthetics in these applications, it is particularly useful to evaluate aging in plastics based on the relationship between color and strength. The wide application of 3D printing in various industries necessitates understanding material properties under aging conditions. This study examines the effects of aging on the mechanical behavior of polylactic acid (PLA) with three different colors (yellow, orange, and red) and three different infill ratios (20%, 60%, and 100%). The samples underwent an accelerated aging process of 432 h, which included 8 h of UV radiation, 15 min of water spraying, followed by 3 h and 45 min with the UV lamps turned off. Tensile tests, bending tests, hardness measurements, and color evaluations were conducted on the samples, linking the color changes after aging with the materials’ mechanical properties. The results show that after aging, yellow samples with a 100% infill ratio exhibited a 6.9% increase in tensile strength (44.50 MPa to 47.58 MPa). Orange samples with a 100% infill ratio were less affected by aging, while red samples experienced a decrease in tensile strength across all infill ratios. Regarding bending force, increases were observed in the orange, yellow, and red samples by 10.37%, 25.05%, and 8.87%, respectively. This study underscores the importance of color selection when designing 3D-printed materials for long-term applications. Full article

(This article belongs to the Special Issue Experimental Testing, Manufacturing and Numerical Modelling of Composite and Sandwich Structures (Second Edition))

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10 pages, 2685 KiB

Open AccessArticle

Modified Magnesium Oxysulfate Foam Cement Doped with Iron Tailings

by Yitong Fang, Baoluo Xu, Lisha Fu, Le Chen, Zilong Chen, Wanjun Hao and Kexi Zhang

Materials 2024, 17(23), 5907; https://doi.org/10.3390/ma17235907 (registering DOI) - 2 Dec 2024

Abstract

The enhancement of the utilization rate of solid waste, along with balancing the comprehensive performance of materials, presents a significant challenge in the development of new functional building materials. This study examined the effects of high concentrations of iron tailing powder on the [...] Read more.

The enhancement of the utilization rate of solid waste, along with balancing the comprehensive performance of materials, presents a significant challenge in the development of new functional building materials. This study examined the effects of high concentrations of iron tailing powder on the crystallization characteristics, pore structure, compressive strength, and water absorption of modified magnesium oxysulfate (MOS) foam cement with different dry densities. Furthermore, employing chemical foaming technology, the study characterized and analyzed the microstructure of modified MOS foam cement hydration products through scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD). The results indicated that the addition of an acidic modifier effectively facilitated the hydration reaction in the MgO-MgSO₄-H₂O system, enhancing the micro-crystallization characteristics of MOS foam cement. The internal pores were uniformly round, with a dense crystal structure within the pore walls. The compressive strength of the material with 40% dry density A08 grade iron tailing powder reached 6.83 MPa, and the lowest water absorption was 5.32% at a dry density of A09. Full article

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18 pages, 5740 KiB

Open AccessArticle

A Novel Simulation Model of Shielding Performance Based on the Anisotropic Magnetic Property of Magnetic Shields

by Yuzheng Ma, Minxia Shi, Leran Zhang, Teng Li, Xuechen Ling, Shuai Yuan, Hanxing Wang and Yi Gao

Materials 2024, 17(23), 5906; https://doi.org/10.3390/ma17235906 (registering DOI) - 2 Dec 2024

Abstract

To achieve a near-zero magnetic field environment, the use of permalloy sheets with high-performance magnetic properties is essential. However, mainstream welding processes for magnetically shielded rooms (MSRs), such as argon arc welding and laser welding, can degrade the magnetic properties of the material. [...] Read more.

To achieve a near-zero magnetic field environment, the use of permalloy sheets with high-performance magnetic properties is essential. However, mainstream welding processes for magnetically shielded rooms (MSRs), such as argon arc welding and laser welding, can degrade the magnetic properties of the material. Additionally, neglecting the anisotropy of permalloy sheets can introduce unpredictable errors in the evaluation of MSR performance. To address this issue, this paper proposes a modified model for calculating the shielding factor (SF) of MSRs that incorporates the anisotropic magnetic characteristics of permalloy sheets. These characteristics were measured using a two-dimensional single sheet tester (2D-SST). A high-precision measurement system was developed, comprising a 2D-SST (to generate two-dimensional magnetic fields and sense the induced B and H signals) and a control system (to apply in-phase 2D excitation signals and amplify, filter, and record the B and H data). Hysteresis loops were tested at low frequencies (0.1–9 Hz) and under different magnetization states (0.1–0.6 T) in two orientations—parallel and perpendicular to the annealing magnetic field—to verify anisotropy under varying conditions. Initial permeability, near-saturation magnetization, and basic magnetization curves (BM curves) were measured across different directions to provide parameters for simulations and theoretical calculations. Based on these measurements and finite element simulations, a mathematical model was developed to adjust the empirical coefficient λ used in theoretical SF calculations. The results revealed that the ratio of empirical coefficients in different directions is inversely proportional to the ratio of magnetic permeability in the corresponding directions. A verification group was established to compare the original model and the modified model. The mean squared error (MSE) between the original model and the finite element simulation was 49.97, while the MSE between the improved model and the finite element simulation was reduced to 0.13. This indicates a substantial improvement in the computational accuracy of the modified model. Full article

(This article belongs to the Special Issue Preparation, Electromagnetic Absorption and Shielding Properties of Electromagnetic Functional Materials)

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