Materials

19 pages, 5506 KiB

Open AccessArticle

Binder-Less Molybdenum Doped CoO Based Integrated Electrodes Fabricated by Electric Discharge Corrosion for High-Efficiency Supercapacitors

by Ri Chen, Zehan Xu, Yunying Xu, Tujun Lei, Dawei Liu, Chunlong Chen, Wenxia Wang, Igor Zhitomirsky, Muchao Qu and Guoying Zhang

Materials 2025, 18(1), 80; https://doi.org/10.3390/ma18010080 (registering DOI) - 27 Dec 2024

Abstract

Due to its low cost, natural abundance, non-toxicity, and high theoretical capacitance, cobalt oxide (CoO) stands as a promising candidate electrode material for supercapacitors. In this study, binder-less molybdenum doped CoO (Mo@CoO) integrated electrodes were one-step fabricated using a simple electric discharge corrosion [...] Read more.

Due to its low cost, natural abundance, non-toxicity, and high theoretical capacitance, cobalt oxide (CoO) stands as a promising candidate electrode material for supercapacitors. In this study, binder-less molybdenum doped CoO (Mo@CoO) integrated electrodes were one-step fabricated using a simple electric discharge corrosion (EDC) method. This EDC method enables the direct synthesis of Mo@CoO active materials with oxygen vacancy on cobalt substrates, without any pre-made templates, conductive additives, or chemicals. Most importantly, the EDC method enables precise control over the discharge processing parameter of pulse width, which facilitates tailoring the surface morphologies of the as-prepared Mo@CoO active materials. It was found that the fabricated Mo@CoO based symmetric supercapacitor prepared by a pulse width of 24 μs (Mo@CoO-SCs24) achieved a maximum areal capacitance 36.0 mF cm⁻² (0.15 mA cm⁻²), which is 1.83 and 1.97 times higher than that of Mo@CoO-SCs12 and Mo@CoO-SCs36. Moreover, the Mo@CoO-SCs24 devices could be worked at 10 V s⁻¹, which demonstrates their fast charge/discharge characteristic. These results demonstrated the significant potential of the EDC strategy for efficiency fabricating various metal oxide binder-less integrated electrodes for various applications, like supercapacitors, batteries and sensors. Full article

(This article belongs to the Special Issue Energy Storage Materials and Devices: Design, Properties and Mechanisms)

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17 pages, 7354 KiB

Open AccessArticle

Analysis of Tool Wear in Finish Turning of Titanium Alloy Ti-6Al-4V Under Minimum Quantity Lubrication Conditions Observed with Recurrence Quantification Analysis

by Joanna Lisowicz, Krzysztof Krupa, Kamil Leksycki, Rafał Rusinek and Szymon Wojciechowski

Materials 2025, 18(1), 79; https://doi.org/10.3390/ma18010079 (registering DOI) - 27 Dec 2024

Abstract

Titanium alloys, particularly Ti-6Al-4V, are widely used in many industries due to their high strength, low density, and corrosion resistance. However, machining these materials is challenging due to high strength at elevated temperatures, low thermal conductivity, and high chemical reactivity. This study investigates [...] Read more.

Titanium alloys, particularly Ti-6Al-4V, are widely used in many industries due to their high strength, low density, and corrosion resistance. However, machining these materials is challenging due to high strength at elevated temperatures, low thermal conductivity, and high chemical reactivity. This study investigates Recurrence Plot (RP) and Recurrence Quantification Analysis (RQA) to analyze tool wear during the finish turning of Ti-6Al-4V. The tests were conducted under Minimum Quantity Lubrication (MQL). Three inserts (two coated, one uncoated) were tested, and tool life was evaluated based on material removal volume. The issue of tool exploitation and process reliability is crucial, as it directly impacts machining performance. Results show that the uncoated insert outperformed the coated ones. RQA parameters indicated a stable-to-unstable transition in coated inserts but not in the uncoated insert. This suggests that recurrence analysis can monitor cutting dynamics in coated insert machining, but further research is needed for uncoated tools. This paper’s novelty lies in applying RP and RQA to diagnose tool wear in titanium alloy machining under MQL conditions, a method not previously explored in this context. Full article

(This article belongs to the Special Issue Surface Inspection and Description in Metrology and Tribology (Second Volume))

14 pages, 6163 KiB

Open AccessArticle

In-Volume Glass Modification Using a Femtosecond Laser: Comparison Between Repetitive Single-Pulse, MHz Burst, and GHz Burst Regimes

by Manon Lafargue, Théo Guilberteau, Pierre Balage, Bastien Gavory, John Lopez and Inka Manek-Hönninger

Materials 2025, 18(1), 78; https://doi.org/10.3390/ma18010078 (registering DOI) - 27 Dec 2024

Abstract

In this study, we report, for the first time, to the best of our knowledge, on in-volume glass modifications produced by GHz bursts of femtosecond pulses. We compare three distinct methods of energy deposition in glass, i.e., the single-pulse, MHz burst, and GHz [...] Read more.

In this study, we report, for the first time, to the best of our knowledge, on in-volume glass modifications produced by GHz bursts of femtosecond pulses. We compare three distinct methods of energy deposition in glass, i.e., the single-pulse, MHz burst, and GHz burst regimes, and evaluate the resulting modifications. Specifically, we investigate in-volume modifications produced by each regime under varying parameters such as the pulse/burst energy, the scanning velocity, and the number of pulses in the burst, with the aim of establishing welding process windows for both sodalime and fused silica. Full article

(This article belongs to the Special Issue Fabrication of Advanced Materials)

21 pages, 3509 KiB

Open AccessArticle

Flow Behavior Analysis of the Cold Rolling Deformation of an M50 Bearing Ring Based on the Multiscale Finite Element Model

by Wenting Wei, Zheng Liu, Qinglong Liu, Guanghua Zhou, Guocheng Liu, Yanxiong Liu and Lin Hua

Materials 2025, 18(1), 77; https://doi.org/10.3390/ma18010077 (registering DOI) - 27 Dec 2024

Abstract

Through the ferrite single-phase parameters of M50 bearing steel obtained based on nanoindentation experiments and the representative volume element (RVE) model established based on the real microstructure of M50, this paper established a multiscale finite element model for the cold ring rolling of [...] Read more.

Through the ferrite single-phase parameters of M50 bearing steel obtained based on nanoindentation experiments and the representative volume element (RVE) model established based on the real microstructure of M50, this paper established a multiscale finite element model for the cold ring rolling of M50 and verified its accuracy. The macroscale and mesoscale flow behaviors of the ring during the cold rolling deformation process were examined and explained. The macroscopic flow behavior demonstrated that the stress distribution was uniform following rolling. The equivalent plastic strain (PEEQ) grew stepwise over time, with the raceway showing the highest PEEQ. The mesoscopic simulation revealed that the stress was concentrated in the cementite, and the maximum occurred at the junction of the ferrite and cementite. The largest PEEQ was found in the ferrite matrix positioned between the two adjacent cementites. The cementite flew with the deformation of the ferrite. The radial displacement of the cementite decreased from the edge of the raceway to both ends and decreased from the inner to the outer surface. Its axial displacement was basically the same on the inner surface and decreased from the inner to the outer surface. Its circumferential displacement decreased from the inner and outer surfaces to the intermediate thickness region. Full article

(This article belongs to the Special Issue Metalworking Processes: Theoretical and Experimental Study)

12 pages, 1317 KiB

Open AccessCommunication

Improving Corrosion Resistance of Zircaloy-4 via High-Current Pulsed Electron Beam Surface Irradiation

by Shen Yang, Heran Yao, Zhiyong Hu and Tao Chen

Materials 2025, 18(1), 76; https://doi.org/10.3390/ma18010076 (registering DOI) - 27 Dec 2024

Abstract

Zircaloy-4 is extensively used in nuclear reactors as fuel element cladding and core structural material. However, the safety concerns post-Fukushima underscore the need for further enhancing its high-temperature and high-pressure water-side corrosion resistance. Therefore, this study aimed to investigate the effects of high-current [...] Read more.

Zircaloy-4 is extensively used in nuclear reactors as fuel element cladding and core structural material. However, the safety concerns post-Fukushima underscore the need for further enhancing its high-temperature and high-pressure water-side corrosion resistance. Therefore, this study aimed to investigate the effects of high-current pulsed electron beam (HCPEB) irradiation on the microstructures and corrosion resistance of Zircaloy-4, with the goal of improving its performance in nuclear applications. Results showed that after irradiation, the cross-section of the sample could be divided into three distinct layers: the outermost melted layer (approximately 4.80 μm), the intermediate heat-affected zone, and the bottom normal matrix. Large numbers of twin martensites were induced within the melted layer, which became finer with increasing irradiation times. Additionally, plenty of ultrafine/nanoscale grains were observed on the surface of the sample pulsed 25 times. Zr(Fe, Cr)₂ second-phase particles (SPPs) were dissolved throughout the modified layer and Fe and Cr elements were uniformly distributed under the action of HCPEB. As a result, the corrosion resistance of the sample pulsed 25 times was significantly improved compared to the initial one. Research results confirmed that HCPEB irradiation is an effective method in improving the service life of Zircaloy-4 under extreme environmental conditions. Full article

(This article belongs to the Special Issue Microstructures and Properties of Corrosion-Resistant Alloys)

23 pages, 7905 KiB

Open AccessArticle

Energy Efficiency in Turning: A Comparative Analysis of Screw Drive and Linear Drive CNC Machine Tools

by Agnieszka Terelak-Tymczyna, Krzysztof Marchelek, Ryszard Daniel Ziętek, Paweł Frankowski, Agata Zubkiewicz and Karol Miądlicki

Materials 2025, 18(1), 75; https://doi.org/10.3390/ma18010075 (registering DOI) - 27 Dec 2024

Abstract

This paper presents a comparative analysis of the energy efficiency of screw drive and linear drive CNC machine tools in turning operations. Two CNC lathes were investigated, one equipped with screw drives and the other with linear drives, during the turning of specially [...] Read more.

This paper presents a comparative analysis of the energy efficiency of screw drive and linear drive CNC machine tools in turning operations. Two CNC lathes were investigated, one equipped with screw drives and the other with linear drives, during the turning of specially prepared parts. The research examines active and reactive energy consumption, offering insights into the energy efficiency of different drive technologies. The analysis indicates that lathes with linear drives exhibited a higher reactive power consumption (8 kVar) during idle operation in comparison to those with screw drives (1.2 kVar). However, both drive systems demonstrated comparable potential for reducing reactive power consumption through implementing compensation techniques, with a reduction in reactive power consumption of nearly 70%. For both drive systems, the reduction in power use with compensation was at the level of 23–30% for screw drives and 36–47% for linear drives. The study highlights the importance of considering both active and reactive energy in evaluating the energy efficiency of machine tools. The findings contribute to a deeper understanding of energy consumption in turning processes, aiding in the selection and optimization of drive systems for improved sustainability in manufacturing. Future research should explore tool wear impacts, machine-specific energy optimization, and AI-driven solutions for real-time energy management. Full article

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13 pages, 4808 KiB

Open AccessArticle

Impact of Ce Doping on the Relaxor Behavior and Electrical Properties of Sr_0.4Ba_0.6Nb₂O₆ Ferroelectric Ceramics

by Yingying Zhao, Pu Mao, Ruirui Kang, Ziao Li and Fang Kang

Materials 2025, 18(1), 74; https://doi.org/10.3390/ma18010074 (registering DOI) - 27 Dec 2024

Abstract

In this work, the rare earth element Ce was incorporated into the A-site of Sr_0.4Ba_0.6Nb₂O₆ ferroelectric ceramics, which was prepared using the conventional solid state reaction method and sintered under different procedures. A comprehensive investigation was [...] Read more.

In this work, the rare earth element Ce was incorporated into the A-site of Sr_0.4Ba_0.6Nb₂O₆ ferroelectric ceramics, which was prepared using the conventional solid state reaction method and sintered under different procedures. A comprehensive investigation was conducted to assess the impact of Ce doping and varying sintering procedures on both the relaxor characteristics and electrical properties of the ceramics. When sintered at 1300 °C for 4 h, the grains exhibited an isometric shape. However, when the sintering temperature increases and the holding time prolongs, the grain size increases and presents columnar crystal. The change tendency of dielectric constant is similar with that of the grain size, and the dielectric peak value of samples sintered at 1300 °C for 4 h is the lowest. But the sintering procedure has almost no influence on the Curie point, which notably decreases as the Ce content rises and is primarily governed by the composition. The diffuseness fitting results and the deviation from the Curie–Weiss law indicate that relaxor characteristics increase with the Ce content increasing. The polarization electric (P-E) loops become slimmer with increasing Ce content, verifying the relaxor behavior variation of samples. As a result, the P_max and P_r values decrease and the P_max − P_r value increases with increasing Ce content. Notably, the energy storage density and efficiency enhance obviously with higher Ce content, which is attributed to the relaxor behavior. Furthermore, at a Ce content of 4 mol%, the P-E loops and energy storage performance exhibit remarkable frequency and fatigue stability. Therefore, this study offers valuable insights into the investigation of relaxor behavior and the influence of rare earth elements on the properties of tungsten bronze-structured ferroelectrics. Full article

(This article belongs to the Special Issue Preparation, Properties and Applications of Ferroelectric Materials)

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20 pages, 15697 KiB

Open AccessArticle

The Effect of the Addition of Silicon Dioxide Particles on the Tribological Performance of Vegetable Oils in HCT600X+Z/145Cr46 Steel Contacts in the Deep-Drawing Process

by Tomasz Trzepieciński, Krzysztof Szwajka, Marek Szewczyk, Joanna Zielińska-Szwajka, Ján Slota and Ľuboš Kaščák

Materials 2025, 18(1), 73; https://doi.org/10.3390/ma18010073 (registering DOI) - 27 Dec 2024

Abstract

Friction is an unfavourable phenomenon in deep-drawing forming processes because it hinders the deformation processes and causes deterioration of the surface quality of drawpieces. One way to reduce the unfavourable effect of friction in deep-drawing processes is to use lubricants with the addition [...] Read more.

Friction is an unfavourable phenomenon in deep-drawing forming processes because it hinders the deformation processes and causes deterioration of the surface quality of drawpieces. One way to reduce the unfavourable effect of friction in deep-drawing processes is to use lubricants with the addition of hard particles. For this reason, this article presents the results of friction tests of dual-phase HCT600X+Z steel sheets using the flat die strip drawing test. Sunflower oil and rapeseed oil with the addition of 1, 5 and 10 wt.% of silicon dioxide (SiO₂) particles were used as lubricants. Tests were also carried out in dry friction conditions and lubricated conditions using SiO₂-modified oils and oils without the addition of particles, as a reference. Tests were carried out at different pressure values between 2 and 8 MPa. The effect of friction on the change in sheet surface roughness was also examined. For the entire range of pressures analysed, pure sunflower oil showed lower efficiency in reducing the coefficient of friction compared to pure rapeseed oil. In the pressure range of 4–8 MPa, the lubricants with 5 wt.% and 10 wt.% of particles were more effective in reducing friction than the biolubricant with the addition of 1 wt.% of SiO₂. The lowest average roughness was observed for lubrication with sunflower oil containing 5 wt.% of particles. In relation to rapeseed oil, the addition of 10 wt.% of SiO₂ provided a sheet surface with the lowest average roughness. Full article

(This article belongs to the Special Issue Surface Inspection and Description in Metrology and Tribology (Second Volume))

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15 pages, 14093 KiB

Open AccessArticle

Effect of Si Addition on Structure and Corrosion Resistance of FeCoNiCr High-Entropy Alloy Coating

by Wenqiang Li, Jie Lian, Dengfeng Wang, Suo Zhang, Chengfu Han, Zhenyu Du and Fushan Li

Materials 2025, 18(1), 72; https://doi.org/10.3390/ma18010072 (registering DOI) - 27 Dec 2024

Abstract

In this study, Fe₆₀Co_10−xNi₁₅Cr₁₅Si_x (x = 0, 4, and 8) powders were successfully prepared using the aerosol method and employed to produce high-entropy coatings on Q235 steel via laser cladding. The microstructure and phase [...] Read more.

In this study, Fe₆₀Co_10−xNi₁₅Cr₁₅Si_x (x = 0, 4, and 8) powders were successfully prepared using the aerosol method and employed to produce high-entropy coatings on Q235 steel via laser cladding. The microstructure and phase composition of the coatings were analyzed using scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction. Corrosion resistance and potential were evaluated through electrochemical analysis and Kelvin probe force microscopy. The results show that the Fe₆₀Co_10−xNi₁₅Cr₁₅Si_x coatings exhibit excellent metallurgical bonding with no visible porosity or cracks. The coating primarily consists of an FCC structure; however, as the Si content increases, the structure transitions to a mixed FCC + BCC phase. The addition of Si also refines the grain size in the alloy system. Electrochemical analysis reveals that the Si0 and Si4 coatings exhibit similar corrosion behavior, while the Si8 coating shows a significant drop in corrosion potential, reducing its corrosion resistance. As the Si content increases, grain refinement leads to more grain boundaries, but the corrosion resistance decreases due to the lower corrosion performance of Si compared to Co. Considering both cost and corrosion resistance, the Si4 coating offers a balance of low cost and excellent corrosion resistance. Full article

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

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18 pages, 5907 KiB

Open AccessArticle

Improvement of Bending Stiffness of Timber Beams with Ultra-High-Modulus-Carbon-Fibre-Reinforced Polymer Sheets

by Michał Marcin Bakalarz and Paweł Grzegorz Kossakowski

Materials 2025, 18(1), 71; https://doi.org/10.3390/ma18010071 (registering DOI) - 27 Dec 2024

Abstract

The bending stiffness of beams represents a pivotal parameter influencing both the dimensions of the elements during their design and their subsequent utilisation. It is evident that excessive deflections can cause discomfort to users and contribute to further structural degradation. The objective of [...] Read more.

The bending stiffness of beams represents a pivotal parameter influencing both the dimensions of the elements during their design and their subsequent utilisation. It is evident that excessive deflections can cause discomfort to users and contribute to further structural degradation. The objective of this study was to enhance the bending stiffness of timber beams by bonding a composite sheet to their external surfaces. A carbon sheet exhibiting an ultra-high modulus of elasticity and low elongation at rupture was employed. Two variables of analysis can be distinguished including whether the reinforcement was applied or not and the number of reinforcement layers. The beams, with nominal dimensions of 80 × 80 × 1600 mm, were subjected to a four-point bending test in order to ascertain their mechanical properties. In total, 15 beams were tested (5 unreinforced and 10 reinforced). The reinforcement had no appreciable impact on the increase in flexural load capacity, with the maximum average increase recorded at 9%. Nevertheless, an increase in stiffness of 34% was observed. Additionally, significant increases were observed in ductility up to 248%. However, the ductile behaviour of the beam occurred after the rupture of the reinforcement. In all instances, the failure was attributed to the fracturing of the wooden components or the UHM CFRP (ultra-high-modulus-carbon-fibre-reinforced polymer) sheet. The numerical analysis proved to be a valuable tool for predicting the stiffness of the wood–composite system, with a relatively low error margin of a few percentage points. The modified approach, based on the equivalent cross-section method, permits the determination of a bilinear load deflection relationship for reinforced beams. The aforementioned curve is indicative of the actual behaviour. Given the propensity for the sudden rupture of reinforcement, the described method of reinforcement is recommended for beams subjected to lower levels of stress. Full article

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17 pages, 3581 KiB

Open AccessArticle

Preparation and Flame-Retardant Mechanism of MgAlZn-Based Hydrotalcite-like Coal Spontaneous Combustion Inhibitor

by Lei Li, Yaohui Li, Zulin Li, Lingling Wu, Jingchuan Gou, Xingrong He, Chenxi Xu, Caijing Xie and Wanyue Wu

Materials 2025, 18(1), 70; https://doi.org/10.3390/ma18010070 (registering DOI) - 27 Dec 2024

Abstract

In this work, the coprecipitation approach was successfully used to create Mg-Al hydrotalcite-like inhibitors modified with varying amounts of Zn, and their characteristics were assessed. The findings indicate that the flame retardancy of Mg-Al hydrotalcite (MgAl-LDHs) is not significantly affected by Zn content. [...] Read more.

In this work, the coprecipitation approach was successfully used to create Mg-Al hydrotalcite-like inhibitors modified with varying amounts of Zn, and their characteristics were assessed. The findings indicate that the flame retardancy of Mg-Al hydrotalcite (MgAl-LDHs) is not significantly affected by Zn content. By adding MgAl-LDHs, the temperature at which the exothermic reaction started to occur was raised from 146.2 °C to 193.6 °C, according to the test of spontaneous combustion tendency. In the excavation route, the utility model can serve as a temporary fire prevention and extinguishment tool. Furthermore, the analysis of the functional group changes during the reaction was conducted using FTIR. After applying MgAl-LDHs, the oxidation of organic groups on the coal surface was clearly prevented, indicating that the inhibitor had a substantial flame-retardant effect on coal. In conclusion, this work creates a material that resembles hydrotalcite and is easy to use, inexpensive, and effective in preventing coal from spontaneously combusting. Full article

(This article belongs to the Special Issue Design, Structure, and Performance of Novel Composite Materials for Sustainable Energy Applications)

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14 pages, 31231 KiB

Open AccessArticle

Effect of Ce Content on Modification Behavior of Inclusions and Corrosion Resistance of 316L Stainless Steel

by Lei Zhao, Jichun Yang and Xiaoyang Fu

Materials 2025, 18(1), 69; https://doi.org/10.3390/ma18010069 (registering DOI) - 27 Dec 2024

Abstract

The changes in the inclusions in 316L stainless steel before and after Ce addition were studied by adding different contents of Ce. The effects of rare earth Ce treatment on the modification of MnS inclusions in steel and the pitting corrosion resistance of [...] Read more.

The changes in the inclusions in 316L stainless steel before and after Ce addition were studied by adding different contents of Ce. The effects of rare earth Ce treatment on the modification of MnS inclusions in steel and the pitting corrosion resistance of 316L stainless steel are studied by field-emission scanning electron microscopy, laser confocal microscopy, the 6% FeCl₃ corrosion weight loss test, and Tafel polarization curve test. The results show that the addition of Ce reduces the corrosion rate of stainless steel in 6% FeCl₃ solution, and reduces the number and size of corrosion pits. The corrosion resistance is the best at a 0.0082% Ce content. In addition, the addition of Ce reduced the corrosion current density of stainless steel in 3.5% NaCl solution and increased the corrosion potential. The corrosion potential increased from −329 mV to −31.4 mV. Through Ce treatment, the grain is refined and the inclusions in the experimental steel are modified. With the increase in rare earth content, Mn S gradually transforms into Ce₂O₂ S inclusions. The morphology of the inclusions gradually change from the original long strips to a spherical shape, and the average size is significantly reduced, which improves the corrosion resistance of the stainless steel. The addition of rare earth Ce plays modifies the inclusions and purifies molten steel. Full article

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21 pages, 11975 KiB

Open AccessArticle

Development and Optimization of a Recyclable Non-Embedded Support System for Thermal Pipeline Trenches in Urban Environments

by Jianfei Ma, Shaohui He and Gangshuai Jia

Materials 2025, 18(1), 68; https://doi.org/10.3390/ma18010068 (registering DOI) - 27 Dec 2024

Abstract

Existing support systems for thermal pipeline trenches often fail to meet the specific needs of narrow strips, tight timelines, and short construction periods in urban environments. This study introduces a novel recyclable, non-embedded support system composed of corrugated steel plates, retractable horizontal braces, [...] Read more.

Existing support systems for thermal pipeline trenches often fail to meet the specific needs of narrow strips, tight timelines, and short construction periods in urban environments. This study introduces a novel recyclable, non-embedded support system composed of corrugated steel plates, retractable horizontal braces, angle steel, and high-strength bolts designed to address these challenges. The system’s effectiveness was validated through prototype testing and optimized using Abaqus finite element simulations. The research hypothesizes that this new support structure will enhance construction efficiency, reduce installation costs, and provide adaptable and sustainable solutions in urban trench applications. Prototype tests demonstrated that the proposed support had maintained safety and stability in trenches of 2 m and 3 m depth under a 58 kPa load and rainfall, as well as the 4 m deep trenches under asymmetric loading of 80 kPa. Optimization of the proposed system included installing two screw jacks on each horizontal brace and adjusting the corrugated plates, resulting in reduced weight, improved node strength, and enhanced screw jack adjustability. Numerical simulations confirmed the optimized system’s reliability in trenches up to 3 m deep, with caution required for deeper applications to avoid structural failure. The proposed support system offers notable advantages over traditional methods by improving construction efficiency, flexibility, and adaptability while also reducing costs, ensuring safety, and promoting environmental sustainability. Its modular design allows for rapid installation and disassembly, making it suitable for projects with strict deadlines and diverse construction conditions. The findings uphold the initial hypotheses and demonstrate the system’s practicality in urban trench projects. Full article

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

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24 pages, 5723 KiB

Open AccessArticle

Impact of Column Support Stiffness on the Mechanical Performance of Flat Frame Structural Systems Supporting Thin-Walled Folded Roofs

by Jacek Abramczyk and Katarzyna Chrzanowska

Materials 2025, 18(1), 67; https://doi.org/10.3390/ma18010067 (registering DOI) - 27 Dec 2024

Abstract

This article presents a new parametric method for shaping flat transverse frame structural systems supporting thin-walled roofs made of flat sheets folded unidirectionally and transformed elastically to various shell forms. The parameterization was limited to one independent variable, that is the stiffness of [...] Read more.

This article presents a new parametric method for shaping flat transverse frame structural systems supporting thin-walled roofs made of flat sheets folded unidirectionally and transformed elastically to various shell forms. The parameterization was limited to one independent variable, that is the stiffness of the support joints. For different discrete values of simulated stiffness, the surface areas of the cross sections of the tensile and compressed elements and the section modulus of the bending elements were calculated so as to obtain the optimized work of the frame and its elements in the assumed load environment. The developed method allows for optimizing the work of frames considered as flat bar structural systems of building halls, taking into account the ultimate and serviceability limit states. The operation of the method is illustrated with an example concerning the formation of a flat frame working under a load characteristic for buildings located in a lowland area in a moderate climate. The authors intend to successively extend the method with new types of frame systems so as to obtain increasingly accurate and universal models defined by means of an increasing number of independent variables. These parameters are related to different forms and inclinations of columns and girders, and different external load types. The successive increase in the parameters defining the computational parametric model of the frame requires the use of increasingly advanced artificial intelligence algorithms to describe the static and strength performance of the buildings shaped, which makes the proposed method universal and the created structural systems effective in various external environments. Full article

(This article belongs to the Special Issue Multiscale Characterization and Computational Modeling/Simulation of Metallic Materials)

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22 pages, 9096 KiB

Open AccessArticle

Assessment of Steel Storage Tank Thickness Obtained from the API 650 Design Procedure Through Nonlinear Dynamic Analysis, Accounting for Large Deformation Effects

by Sobhan Fallah Daryavarsari and Roberto Nascimbene

Materials 2025, 18(1), 66; https://doi.org/10.3390/ma18010066 - 27 Dec 2024

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Abstract

This study evaluates the API 650 design procedure for steel storage tanks, incorporating nonlinear dynamic analysis with large deformation effects. Focusing on seismic vulnerability, the case study examines storage tanks proposed for construction in Naples, Italy, assessing their performance under site-specific seismic conditions. [...] Read more.

This study evaluates the API 650 design procedure for steel storage tanks, incorporating nonlinear dynamic analysis with large deformation effects. Focusing on seismic vulnerability, the case study examines storage tanks proposed for construction in Naples, Italy, assessing their performance under site-specific seismic conditions. A target spectrum and 20 earthquake records were selected to reflect regional seismic characteristics. Initial tank thicknesses were calculated using API 650 guidelines and subsequently analyzed through nonlinear time-history simulations in SAP2000. Results reveal that thicknesses derived from API 650s linear average spectrum equations are insufficient for real seismic demands. Through a trial-and-error methodology, optimal thicknesses were determined to ensure satisfactory performance across all seismic records. Key findings highlight significant variations in mode participation, the frequent occurrence of elephant-foot buckling in tanks with lower

H / R

ratios, and the limitations of linear spectral analysis for realistic earthquake scenarios. Given the vital role of storage tanks in the oil and gas industry, this study emphasizes the need to integrate nonlinear time history analysis into design processes to enhance seismic resilience, particularly in high-risk regions. Full article

(This article belongs to the Special Issue Advances in the Nonlinear Vibration and Structure Dynamics of Composite Materials)

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18 pages, 4855 KiB

Open AccessArticle

Typical Case of Converter Smelting with High Cooling Ratio in Chinese Iron and Steel Enterprises: CO₂ Emission Analysis

by Huapeng Yang, Chao Feng, Yubin Li, Feihong Guo, Rong Zhu, Minke Zhang, Xing Wang, Xin Du, Liyun Huo, Fuxin Wen, Tao Ren, Guangsheng Wei and Fuhai Liu

Materials 2025, 18(1), 65; https://doi.org/10.3390/ma18010065 - 27 Dec 2024

Viewed by 33

Abstract

In this study, the effects of using different scrap ratios in a converter on carbon emissions were analyzed based on life cycle assessment (LCA) theory, and the carbon emissions from the converter were evaluated with the use of coke and biochar as heating [...] Read more.

In this study, the effects of using different scrap ratios in a converter on carbon emissions were analyzed based on life cycle assessment (LCA) theory, and the carbon emissions from the converter were evaluated with the use of coke and biochar as heating agents at high scrap ratios. In this industrial experiment, the CO₂ emissions during the converter smelting process decreased with the increase in the scrap steel ratio. For every 1% increase in the scrap steel ratio, the carbon emissions during the steelmaking process decreased by 14.09 kgCO₂/t steel. Based on statistical data for the actual use of a charcoal heating agent in the converter, the relationship between the utilization coefficient of the heating agent and the scrap ratio was calculated as

η = 7.698 \times 10^{2} x^{- 2.596} .

When biochar was used as a converter heating agent, the scrap ratio required to achieve the lowest carbon emissions was 36%, and the converter emissions could be reduced by 172 kgCO₂/t·steel relative to the use of coke. The use of biochar as a converter heating agent can contribute to the elimination of 330 million tons of scrap through furnace–converter long-process steelmaking, yielding an annual reduction in CO₂ emissions of 158 million tons. Full article

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13 pages, 5168 KiB

Open AccessArticle

Phase Transformation Behavior, Mechanical Properties Under Thermal Stress, and Slag-Induced Erosion of 2–4 mol% CeO₂-Doped CaO-Stabilized Zirconia

by Janghoon Kim, Hwanho Jeon, Kanghee Jo, Hwanseok Lee and Heesoo Lee

Materials 2025, 18(1), 64; https://doi.org/10.3390/ma18010064 - 27 Dec 2024

Viewed by 54

Abstract

We investigated the phase transitions, mechanical properties, and chemical durability of a composition of 9 mol% CaO-stabilized zirconia (9CSZ) doped with 2–4 mol% CeO₂ under thermal stress against molten slag. The monoclinic phase fraction of 9CSZ was 7.14% at room temperature, and [...] Read more.

We investigated the phase transitions, mechanical properties, and chemical durability of a composition of 9 mol% CaO-stabilized zirconia (9CSZ) doped with 2–4 mol% CeO₂ under thermal stress against molten slag. The monoclinic phase fraction of 9CSZ was 7.14% at room temperature, and CSZ doped with 2–4 mol% CeO₂ showed a slightly lower value of 5.55–3.72%, with only a minor difference between them. The microstructure of 9CSZ doped with 2–3 mol% CeO₂ was similar to that of undoped 9CSZ, whereas the microstructure of 9CSZ doped with 4 mol% CeO₂ exhibited noticeable grain refinement. The mechanical properties of CSZ at room temperature tended to improve as the CeO₂ doping concentration increased. The Vickers hardness increased from 1088.4 HV to 1497.6 HV when the CeO₂ doping amount was 4 mol%, and the specific wear amount decreased from 1.5941 to 1.1320 × 10⁵ mm³/Nm. This tendency remained similar even after applying thermal stress. The monoclinic phase fraction of 9CSZ increased from 7.14% to 67.71% after the erosion experiment with the CaF₂-based slag. CeO₂-doped CSZ had a lower monoclinic phase fraction than CSZ after the erosion experiment, but as CeO₂ content increased from 2 to 4 mol%, the fraction rose to 4.07%, 30.85%, and 77.11%. Full article

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(a) XRD diffraction patterns of CeO2-doped 9CSZ powder calcinated at 1600 °C (•: monoclinic phase, ◼: tetragonal or cubic phase), (b) Phase fraction determined through Rietveld refinement. Full article ">Figure 2
Ce 3d XPS spectrum and deconvoluted cures for Ce3+ and Ce4+ after background subtraction of (a) 2Ce_CSZ, (b) 3Ce_CSZ, and (c) 4Ce_CSZ. Full article ">Figure 3
FE-SEM images and average grain sizes of (a) 9CSZ, (b) 2CeO2_CSZ, (c) 3CeO2_CSZ, and (d) 4CeO2_CSZ specimens after sintering. Full article ">Figure 4
(a) XRD diffraction patterns of CeO2-doped 9CSZ after thermal shock (△400 °C) (•: monoclinic phase, ◼: tetragonal or cubic phase), (b) Phase fraction determined through Rietveld refinement. Full article ">Figure 5
Vickers hardness of CeO2-doped CSZ before (black scattered point) and after (red scattered point) post-heat treatment. Full article ">Figure 6
Flexural strength of CeO2-doped CSZ before(black scattered point) and after (red scattered point) post-heat treatment. Full article ">Figure 7
Specific wear amount of CeO2-doped CSZ before (black scattered point) and after (red scattered point) post-heat treatment. Full article ">Figure 8
X-ray diffraction patterns of CeO2-doped 9CSZ after erosion experiment in slag. Full article ">

10 pages, 2823 KiB

Open AccessArticle

Lu₃Al₅O₁₂:Ce³⁺ Fluorescent Ceramic with Deep Traps: Thermoluminescence and Photostimulable Luminescence Properties

by Junwei Zhang, Miao Zhao, Qiao Hu, Renjie Jiang, Hao Ruan and Hui Lin

Materials 2025, 18(1), 63; https://doi.org/10.3390/ma18010063 - 27 Dec 2024

Viewed by 75

Abstract

Electron-trapping materials have attracted a lot of attention in the field of optical data storage. However, the lack of suitable trap levels has hindered its development and application in the field of optical data storage. Herein, Lu₃Al₅O₁₂:Ce [...] Read more.

Electron-trapping materials have attracted a lot of attention in the field of optical data storage. However, the lack of suitable trap levels has hindered its development and application in the field of optical data storage. Herein, Lu₃Al₅O₁₂:Ce³⁺ fluorescent ceramics were developed as the optical storage medium, and high-temperature vacuum sintering induced the formation of deep traps (1.36 eV). The matrix based on the garnet-structured material ensures excellent rewritability. By analyzing the thermoluminescence and photostimulable luminescence, it is found that the transition of electrons provided by Ce³⁺ between the conduction band and trap levels offers the possibility for optical data storage. As evidence of its application, the optical information encoding using 254 nm light and decoding using a light stimulus and thermal stimulus were applied. These findings are expected to provide candidate material for novel optical storage technology, and further promote the development of advanced information storage technology. Full article

(This article belongs to the Special Issue Feature Papers in Materials Physics (2nd Edition))

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(a) XRD patterns of LuAG:xCe (x = 0.011, 0.013 and 0.015). (b) Rietveld refinement of LuAG:0.013Ce. (c) PLE and PL spectra of LuAG:xCe (λem = 512 nm, λex = 437 nm). (d) SEM image of LuAG:0.013Ce3+. Full article ">Figure 2
(a) TL curves of LuAG:xCe3+. (b) TL curves with different heating rate of LuAG:0.013Ce3+ (Inset: Heating rate plots of LuAG:0.013Ce3+). (c) TL curves of LuAG:0.013Ce3+ for different delay time (Inset: Integral area of TL curves as function of delay time). (d) The rewritability test of LuAG:0.013Ce3+. Full article ">Figure 3
(a) TL curves of LuAG:Ce before and after annealing at 1000 °C. (b) A diagram of the information storage principle. Full article ">Figure 4
(a) Diagram of the optical storage application. (b) Photos of LuAG:Ce under (i) sunlight; (ii) under 254 nm light; (iii) the sample was covered with photomask “U”, “S”, “S”, and “T” for 5 min and heated to 250 °C. Full article ">Figure 5
Sample was excited by 254 nm light for 15 min. (a) Luminescence decay curve of the sample. (b) Photostimulated luminescence (PSL) curves of the ceramic by 980 nm laser in different power settings. Full article ">

15 pages, 4340 KiB

Open AccessArticle

Development of a Fire-Retardant and Sound-Insulating Composite Functional Sealant

by Shiwen Li, Mingyu Wang, Jinchun Tu, Bingrong Wang, Xiaohong Wang and Kexi Zhang

Materials 2025, 18(1), 62; https://doi.org/10.3390/ma18010062 - 27 Dec 2024

Viewed by 102

Abstract

The use of traditional sealing materials in buildings poses a significant risk of fire and noise pollution. To address these issues, we propose a novel composite functional sealant designed to enhance fire safety and sound insulation. The sealant incorporates a unique four-component filler [...] Read more.

The use of traditional sealing materials in buildings poses a significant risk of fire and noise pollution. To address these issues, we propose a novel composite functional sealant designed to enhance fire safety and sound insulation. The sealant incorporates a unique four-component filler system consisting of carbon nanotubes (CNTs) decorated with layered double hydroxides (LDHs), ammonium dihydrogen phosphate (ADP), and artificial marble waste powder (AMWP), namely CLAA. The CNTs/LDHs framework provides structural support and enhances thermal stability, while the ADP layer acts as a protective barrier and releases non-combustible gases during combustion. AMWP particles contribute to sound insulation by creating impedance mismatches. The resulting composite functional sealant exhibits improved mechanical properties. In terms of flame retardancy, it boasts the lowest peak heat release rate (PHRR) of 224.83 kW/m² and total smoke release (TSR) of 981.14 m²/m², achieving the V-0 classification. Furthermore, its thermal degradation characteristics reveal a notably higher carbon residue rate. Additionally, the sound insulation capability has been significantly enhanced, with an average sound insulation level of 43.48 dB. This study provides a promising solution for enhancing the fire safety and acoustic properties of building sealing materials. Full article

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17 pages, 6981 KiB

Open AccessArticle

Influence of Different Spot Pattern Lasers on Cleaning Effect of TC4 Titanium Alloy

by Xinqiang Ma, Tengchao Liu, Yuan Ren, Yanlu Zhang, Zifa Xu, Wei Cheng, Zhenzhen Zhang, Yongmei Zhu and Qinhe Zhang

Materials 2025, 18(1), 61; https://doi.org/10.3390/ma18010061 - 27 Dec 2024

Viewed by 83

Abstract

This study employed different spot pattern lasers to clean the oxide film on the surface of a TC4 titanium alloy. The variation in temperature field and ablation depth during the laser cleaning process was simulated by establishing a finite element model. The effects [...] Read more.

This study employed different spot pattern lasers to clean the oxide film on the surface of a TC4 titanium alloy. The variation in temperature field and ablation depth during the laser cleaning process was simulated by establishing a finite element model. The effects of various laser processing parameters on the micromorphology, elemental composition, and surface roughness of the TC4 titanium alloy were analyzed. The results show that as the laser energy density increases, both the temperature field and ablation depth increase as well. Under optimal laser processing parameters, the laser energy density is 5.27 J/cm², with a repetition frequency of 300 kHz and a scanning speed of 6000 mm/s. A comparison of the cleaning effects of Gaussian pulse lasers and Flat-top pulse lasers reveals that the Gaussian pulse laser causes less damage to the TC4 titanium alloy, resulting in lower oxygen content and roughness values after cleaning compared to Flat-top pulse laser cleaning. Full article

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20 pages, 9184 KiB

Open AccessArticle

Tribomechanical Properties of Glazes for Ceramic Tiles: A Novel Protocol for Their Characterization

by Riccardo Fabris, Giulia Masi, Denia Mazzini, Leonardo Sanseverino and Maria Chiara Bignozzi

Materials 2025, 18(1), 60; https://doi.org/10.3390/ma18010060 - 27 Dec 2024

Viewed by 96

Abstract

The aim of the work is to design and validate a characterization protocol for glazes used in the ceramic tile industry to lead manufacturers and researchers towards the formulation of glazes with enhanced wear resistance properties. The focus of the protocol is addressed [...] Read more.

The aim of the work is to design and validate a characterization protocol for glazes used in the ceramic tile industry to lead manufacturers and researchers towards the formulation of glazes with enhanced wear resistance properties. The focus of the protocol is addressed to determine surface parameters that strongly depend on glaze formulation and firing temperature. This protocol includes analytical (e.g., thermal analysis, Vickers microhardness, microstructural investigation, etc.) and technological tests (i.e., impact resistance and surface abrasion resistance test), the latter carried out on ceramic tile samples where four different glazes have been applied. The characterization protocol set in this paper highlights the importance of using both analytical and technological tests for glaze investigations and provides threshold values for specific parameters useful in developing glass-ceramic glazes with enhanced mechanical and tribological properties. Full article

(This article belongs to the Special Issue Sintering of Ceramic Materials)

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18 pages, 8971 KiB

Open AccessArticle

Microstructural Characteristics of Cellulosic Fiber-Reinforced Cement Composite

by Jae-Yoon Han and Young-Cheol Choi

Materials 2025, 18(1), 59; https://doi.org/10.3390/ma18010059 - 27 Dec 2024

Viewed by 147

Abstract

The microstructural evolution and hydration behaviors of cement composites incorporating three natural fibers (abaca, hemp, and jute) were investigated in this study. Mercury intrusion porosimetry was used to assess the microstructural changes, focusing on the pore-size distribution and total porosity. Additionally, the hydration [...] Read more.

The microstructural evolution and hydration behaviors of cement composites incorporating three natural fibers (abaca, hemp, and jute) were investigated in this study. Mercury intrusion porosimetry was used to assess the microstructural changes, focusing on the pore-size distribution and total porosity. Additionally, the hydration characteristics were analyzed using setting time measurements and isothermal calorimetry to track the heat flow and reaction kinetics during cement hydration. Although the fibers tended to delay the initial stages of cement hydration, their internal curing effect ultimately led to a higher long-term compressive strength and a denser microstructure. Consequently, the use of these natural fibers in cement composites can enhance their durability and promote sustainable construction materials. Full article

(This article belongs to the Special Issue Advances in Fiber-Reinforced Cementitious Composites for Concrete and Masonry Structures)

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21 pages, 2621 KiB

Open AccessCommunication

Identifying Crystal Structure of Halides of Strontium and Barium Perovskite Compounds with EXPO2014 Software

by Jorge A. Perez Franco, Antonieta García Murillo, Felipe de J. Carrillo Romo, Issis C. Romero Ibarra and Arturo Cervantes Tobón

Materials 2025, 18(1), 58; https://doi.org/10.3390/ma18010058 - 26 Dec 2024

Viewed by 239

Abstract

The synthesis of ethylamine-based perovskites has emerged to attempt to replace the lead in lead-based perovskites for the alkaline earth elements barium and strontium, introducing chloride halide to prepare the perovskites in solar cell technology. X-ray diffraction studies were conducted, and EXPO2014 software [...] Read more.

The synthesis of ethylamine-based perovskites has emerged to attempt to replace the lead in lead-based perovskites for the alkaline earth elements barium and strontium, introducing chloride halide to prepare the perovskites in solar cell technology. X-ray diffraction studies were conducted, and EXPO2014 software was utilized to resolve the structure. Chemical characterization was performed using Fourier transform infrared spectroscopy, photophysical properties were analyzed through ultraviolet–visible spectroscopy, and photoluminescence properties were determined to confirm the perovskite characteristics. The software employed can determine new crystal structures, as follows: orthorhombic for barium perovskite CH₃CH₂NH₃BaCl₃ and tetragonal for strontium perovskite CH₃CH₂NH₃SrCl₃. The ultraviolet–visible spectroscopy data demonstrated that a temperature increase (90–110 °C) contributed to reducing the band gap from 3.93 eV to 3.67 eV for barium perovskite and from 4.05 eV to 3.84 eV for strontium perovskite. The results exhibited that new materials can be obtained through gentle chemistry and specialized software like EXPO2014, both of which are capable of conducting reciprocal and direct space analyses for identifying crystal structures using powder X-ray diffraction. Full article

(This article belongs to the Special Issue Advances in Structure Analysis of Amorphous and Nanocrystalline Materials (2nd Edition))

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18 pages, 12799 KiB

Open AccessArticle

Development of Application Customization Toolkit (ACT) for 3D Thermal Elastic-Plastic Welding Analysis

by Jaeyong Lee, Dong Hee Park, Juhyeon Park and Do Kyun Kim

Materials 2025, 18(1), 57; https://doi.org/10.3390/ma18010057 - 26 Dec 2024

Viewed by 196

Abstract

A 3D thermal elastic-plastic welding analysis ACT (Application Customization Toolkit) was developed in ANSYS, making welding analysis more accessible. The welding analysis was performed using a decoupled method, separated into thermal and structural analyses. To validate the results, comparisons were made with previous [...] Read more.

A 3D thermal elastic-plastic welding analysis ACT (Application Customization Toolkit) was developed in ANSYS, making welding analysis more accessible. The welding analysis was performed using a decoupled method, separated into thermal and structural analyses. To validate the results, comparisons were made with previous studies for two types of welding: T-joint fillet welding and butt welding. Subsequently, the residual stress and deformation obtained from the welding analysis were applied as initial imperfections in a compression analysis to evaluate the ultimate compressive strength with conventional compression analysis. This comparison allowed for a more realistic assessment of the effects of deformation and residual stress distribution on the structural behaviours. Full article

(This article belongs to the Special Issue Design, Mechanical Properties, and Fatigue Behavior of Materials, Welding Joints and Structures)

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22 pages, 19807 KiB

Open AccessArticle

Experimental Investigation and Modeling of Surface Roughness in BTA Deep Hole Drilling with Vibration Assisted

by Xubo Li, Chuanmiao Zhai, Canjun Wang, Ruiqin Wu, Cunqiang Zang, Shihao Zhang, Bian Guo and Yuewen Su

Materials 2025, 18(1), 56; https://doi.org/10.3390/ma18010056 - 26 Dec 2024

Viewed by 226

Abstract

The surface roughness of hole machining greatly influences the mechanical properties of parts, such as early fatigue failure and corrosion resistance. The boring and trepanning association (BTA) deep hole drilling with axial vibration assistance is a compound machining process of the tool cutting [...] Read more.

The surface roughness of hole machining greatly influences the mechanical properties of parts, such as early fatigue failure and corrosion resistance. The boring and trepanning association (BTA) deep hole drilling with axial vibration assistance is a compound machining process of the tool cutting and the guide block extrusion. At the same time, the surface of the hole wall is also ironed by the axial large amplitude and low-frequency vibration of the guide block. The surface-forming mechanism is very complicated, making it difficult to obtain an effective theoretical analytical model of the surface roughness of the hole wall through kinematic analysis. In order to achieve accurate prediction of the surface quality of the hole wall, the chip-breaking mechanism and the hole wall formation mode of BTA deep hole vibration drilling were analyzed. The influence of drilling spindle speed, feed, amplitude, and vibration frequency on the surface roughness of the hole wall during BTA deep hole vibration drilling was illustrated by a single-factor experiment. A four-factor and three-level test scheme was designed by using the Box–Behnken design (BBD) experimental design method. A surface roughness prediction model for hole wall machining was established based on the response surface methodology. The accuracy of the prediction model was analyzed through ANOVA, and the complex correlation coefficient of the model was 0.9948, indicating that the prediction model can better reflect the mapping relationship between vibration drilling parameters and surface roughness. After optimization analysis and experimental verification, the obtained vibration drilling parameters can achieve smaller surface roughness. The error between the predicted value of the model and the experimental measurement value is 8.65%. The established prediction model is reliable and can accurately predict the surface roughness of the hole wall of BTA deep hole axial vibration drilling, providing a theoretical basis for the surface quality control of the machining hole wall. It can be applied to process optimization in practical production. Full article

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

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Schematic diagram of BTA axial vibration drilling system. Full article ">Figure 2
Axial motion track of the drill and three-dimensional shape of undeformed chips of each cutter tooth in one rotation period (feed fr = 0.05 mm/r, amplitude A = 0.07 mm, frequency rotation ratio ωf = 2). (a) Tool axial motion path, (b) Under different drilling depths of drilling speed n = 1200 r/min and feed f = 0.08 mm/r, (c) Three-dimensional shape of undeformed chips of center and external cutter teeth, (d) Three-dimensional shape of undeformed chips with intermediate cutter teeth. Full article ">Figure 3
Axial motion track of drill bit and three-dimensional shape of undeformed chips of each cutter tooth in one rotation period (feed fr = 0.05 mm/r, amplitude A = 0.07 mm, frequency rotation ratio ωf = 2.5). (a) Tool axial motion path, (b) Under different drilling depths of drilling speed n = 1200 r/min and feed f = 0.08 mm/r, (c) Three-dimensional shape of undeformed chips of center and external cutter teeth, (d) Three-dimensional shape of undeformed chips with intermediate cutter teeth. Full article ">Figure 4
Formation process of surface texture of BTA deep hole machining. Full article ">Figure 5
Tool rotary deep hole drilling machine with internal chip removal. Full article ">Figure 6
Influence of vibration drilling parameters on the surface roughness of the hole wall. (a) fr = 0.06 mm/r, A = 0.14 mm, fw = 27 Hz, (b) n = 800 r/min, A = 0.14 mm, fw = 27 Hz, (c) n = 800 r/min, fr = 0.06 mm/r, fw = 27 Hz, (d) n = 800 r/min, fr = 0.06 mm/r, A = 0.14 mm. Full article ">Figure 6 Cont.
Influence of vibration drilling parameters on the surface roughness of the hole wall. (a) fr = 0.06 mm/r, A = 0.14 mm, fw = 27 Hz, (b) n = 800 r/min, A = 0.14 mm, fw = 27 Hz, (c) n = 800 r/min, fr = 0.06 mm/r, fw = 27 Hz, (d) n = 800 r/min, fr = 0.06 mm/r, A = 0.14 mm. Full article ">Figure 7
3D response surface of hole wall roughness. (a) The effect of speed and feed, (b) The effect of speed and frequency, (c) The effect of speed and amplitude, (d) The effect of feed and frequency, (e) The effect of feed and amplitude, (f) The effect of frequency and amplitude. Full article ">Figure 8
Normal probability of residual surface roughness. Full article ">Figure 9
Contour lines of surface roughness satisfaction function. (a) The effect of speed and feed, (b) The effect of amplitude and vibration frequency. Full article ">Figure 10
Micro-morphology of hole wall surface drilled and formed chips with optimized process parameters. (a) Micro-morphology of hole wall surface, (b) formed chip in BTA deep hole drilling with vibration assistance. Full article ">Figure 11
Wear morphology of BTA deep hole drilling with vibration assistance. (a) The rake face of external cutter teeth, (b) the rake face of the intermediate cutter teeth, (c) the rake face of the center cutter teeth, (d) the flank of external cutter teeth, (e) the flank of intermediate cutter teeth, (f) the flank of center cutter teeth, (g) the edge sizing blade of the external cutter teeth, (h) the first guide block, (i) the second guide block. Full article ">

21 pages, 3368 KiB

Open AccessArticle

Mix Design and Performance Study of High-Strength Self-Compacting Concrete with Manufactured Sand

by Xuan Liu, Xuhao Wang, Yuan Wang, Qianqian Liu, Yuan Tian, Jie Zhou and Yahong Meng

Materials 2025, 18(1), 55; https://doi.org/10.3390/ma18010055 - 26 Dec 2024

Viewed by 260

Abstract

In recent years, research on self-compacting concrete (SCC) has gradually shifted towards high-strength development, while high-strength self-compacting concrete has been widely used in applications such as precast bridge components and high-rise building projects. Using manufactured sand as an aggregate can effectively address the [...] Read more.

In recent years, research on self-compacting concrete (SCC) has gradually shifted towards high-strength development, while high-strength self-compacting concrete has been widely used in applications such as precast bridge components and high-rise building projects. Using manufactured sand as an aggregate can effectively address the challenges posed by the depletion of natural sand resources. This study optimized the mix design for high-strength self-compacting concrete with manufactured sand (MSH-SCC) and explored the effects of the fine aggregate replacement rate, sand ratio, and maximum particle size of coarse aggregate on the performance of MSH-SCC. The results indicated that the optimized mix designs for various strength levels met the performance requirements. The fine aggregate replacement rate and the maximum nominal aggregate size significantly affected the workability of the concrete, while variations in the sand ratio had a smaller impact. The yield stress of the MSH-SCC showed a positive correlation with the fine aggregate replacement rate and the maximum nominal aggregate size, whereas the plastic viscosity reached its maximum value under specific conditions. Additionally, the mix design parameters had a limited effect on the mechanical strength of the MSH-SCC. This study provides a scientific basis for the design of high-strength self-compacting concrete with manufactured sand, contributing to the promotion of manufactured sand use and advancing low-carbon development in the construction industry. Full article

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

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Particle size distribution of the aggregates. Full article ">Figure 2
(a) Schematic diagram of a coaxial cylindrical rheometer. (b) Rheological test operation diagram. Full article ">Figure 3
(a) Tarantula Curve for C40 concrete; (b) Power 45 chart for C40 concrete; (c) Tarantula Curve for C60 concrete; (d) Power 45 chart for C60 concrete; (e) Tarantula Curve for C80 concrete; (f) Power 45 chart for C80 concrete. Full article ">Figure 4
The 28-day compressive strength of the concrete with the original mix proportions and the optimized mix proportions. Full article ">Figure 5
The effect of the manufactured sand replacement rate on the rheology of the concrete. Full article ">Figure 6
The effect of the sand ratio on the rheology of the concrete. Full article ">Figure 7
The effect of the maximum nominal aggregate size on the rheology of the concrete. Full article ">Figure 8
The effect of the replacement rate of the manufactured sand on the compressive strength of the concrete. Full article ">Figure 9
The effect of the sand ratio on the compressive strength of the concrete. Full article ">Figure 10
The effect of the maximum nominal aggregate size on the compressive strength of the concrete. Full article ">Figure 11
(a) SF–fine aggregate replacement rate/strength grade relationship; (b) T500–fine aggregate replacement rate/strength grade relationship; (c) T500–sand ratio/strength grade relationship; (d) PA–maximum nominal aggregate size/strength grade relationship. Full article ">

11 pages, 4514 KiB

Open AccessArticle

Influence of Periodically Varying Slit Widths on Sound Absorption by a Slit Pore Medium

by Keith Attenborough

Materials 2025, 18(1), 54; https://doi.org/10.3390/ma18010054 - 26 Dec 2024

Viewed by 220

Abstract

A simple pore microstructure of parallel, identical, and inclined smooth-walled slits in a rigid solid, for which prediction of its geometrical and acoustic properties is straightforward, can yield useful sound absorption. This microstructure should be relatively amenable to 3D printing. Discrepancies between measurements [...] Read more.

A simple pore microstructure of parallel, identical, and inclined smooth-walled slits in a rigid solid, for which prediction of its geometrical and acoustic properties is straightforward, can yield useful sound absorption. This microstructure should be relatively amenable to 3D printing. Discrepancies between measurements and predictions of normal incidence sound absorption spectra of 3D printed vertical and slanted slit pore samples have been attributed to the rough surfaces of the slit walls and uneven slit cross-sections perpendicular to the printing direction. Theories of the influence of (a) sinusoidal walls and (b) periodically varying uniform slit widths on the normal incidence absorption spectra of a slit pore medium are outlined. Although the slit wall surface and geometrical imperfections due to 3D printing differ from these idealizations, predictions assuming the ideal forms of roughness confirm that pore-wall roughness could account for differences between predictions and data. Pore-wall roughness is predicted to increase both flow resistivity and tortuosity, thereby increasing the low-frequency sound absorption of thin hard-backed layers. The extent to which sinusoidal slit walls or periodically varying uniform slit widths could improve the sound absorption of a low flow resistivity hard-backed layer containing identical vertical slits is explored. Full article

(This article belongs to the Section Porous Materials)

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18 pages, 5913 KiB

Open AccessArticle

Effects of Moisture Infiltration on Interfacial Characteristics of Fiber Asphalt Mastic-Aggregate and the Cracking Resistance of Mixture

by Keke Lou, Silin Jia, Peng Xiao, Haochen Wu and Yuhao Wu

Materials 2025, 18(1), 53; https://doi.org/10.3390/ma18010053 - 26 Dec 2024

Viewed by 247

Abstract

The interfacial properties of fiber asphalt aggregate and the cracking resistance of asphalt mixture are directly affected by moisture infiltration. In order to investigate the correlation between interfacial properties and immersion stability of asphalt mixture, three different types of fiber, including basalt fiber [...] Read more.

The interfacial properties of fiber asphalt aggregate and the cracking resistance of asphalt mixture are directly affected by moisture infiltration. In order to investigate the correlation between interfacial properties and immersion stability of asphalt mixture, three different types of fiber, including basalt fiber (BF), glass fiber (GF), and polyester fiber (PF); five types of fiber contents (0.1% to 0.5% by mass of the mixtures); and two types of aggregates (basalt and limestone) were selected. Experimental methods such as the Bond Strength Test (BBS), Disk-Shaped Compact Tension test (DCT), and interfacial image processing were used in order to assess the strength of interfacial interaction and resistance to cracking under both dry and wet conditions. The results showed that the addition of fibers could enhance fiber asphalt mastic-aggregate interfacial strength; under the influence of moisture infiltration, the interfacial strength showed a significant downward trend. In the process of fiber content increasing from 0.1% to 0.5%, the peak load and fracture energy of fiber asphalt mixtures were first increased and then decreased. The interface between asphalt mastic and aggregate is easier to spalling after being subjected to moisture infiltration, resulting in a decrease in cracking resistance. Compared with the dry environment, after moisture infiltration, the correlation index between interfacial strength and fracture energy is much higher than other influencing factors. The interfacial strength is still an important factor affecting the fracture energy. These findings provide valuable insights for the design and application of more durable asphalt pavement. Full article

(This article belongs to the Special Issue Mechanical Property Research of Advanced Asphalt-Based Materials)

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12 pages, 1942 KiB

Open AccessArticle

Assessment of Radiological Safety of Ceramic Tiles Commonly Used in Polish Buildings

by Aneta Łukaszek-Chmielewska, Marzena Rachwał, Joanna Rakowska, Jakub Ośko, Marta Konop, Bogdan Kosturkiewicz, Mateusz Kosturkiewicz and Marcin Łapicz

Materials 2025, 18(1), 52; https://doi.org/10.3390/ma18010052 - 26 Dec 2024

Viewed by 236

Abstract

The concentration of natural radionuclides ²²⁶Ra, ²³²Th and ⁴⁰K in ceramic tiles manufactured in Poland is presented in this paper. The concentration of natural radioactive isotopes in the tested samples was determined using a low-level digital gamma ray spectrometer equipped [...] Read more.

The concentration of natural radionuclides ²²⁶Ra, ²³²Th and ⁴⁰K in ceramic tiles manufactured in Poland is presented in this paper. The concentration of natural radioactive isotopes in the tested samples was determined using a low-level digital gamma ray spectrometer equipped with an HPGe semiconductor detector. The mean concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K in the analyzed samples were found to be 48 ± 3 Bq∙kg⁻¹, 49 ± 3 Bq∙kg⁻¹ and 476 ± 23 Bq∙kg⁻¹, respectively. The world mean concentrations of these radionuclides (50 Bq·kg⁻¹, 50 Bq·kg⁻¹ and 500 Bq·kg⁻¹, respectively) were not exceeded. Furthermore, in order to ascertain the level of gamma radiation exposure, fundamental radiation protection parameters were established: radioactivity concentration indicator/gamma ray indicator (I_γ), indoor dose rate (D_in) and annual indoor effective dose (E_in). In the case of the investigated ceramic tiles, it was established that the parameters were not higher than the limit values, except the indoor gamma radiation dose rate which was found to be 1.5 times higher than the world average. Therefore, the findings of this study indicate that the utilization of the examined ceramic tiles in constructions should be approached with a degree of caution. Full article

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

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14 pages, 5596 KiB

Open AccessArticle

Microstructure and Mechanical Properties of Rolled (TiC + Ti1400)/TC4 Composites

by Bowen Li, Shanna Xu, Ni He, Guodong Sun, Mingyang Li, Longlong Dong and Mingjia Li

Materials 2025, 18(1), 51; https://doi.org/10.3390/ma18010051 - 26 Dec 2024

Viewed by 217

Abstract

One of the long-standing challenges in the field of titanium matrix composites is achieving the synergistic optimization of high strength and excellent ductility. When pursuing high strength characteristics in materials, it is often difficult to consider their ductility. Therefore, this study prepared a [...] Read more.

One of the long-standing challenges in the field of titanium matrix composites is achieving the synergistic optimization of high strength and excellent ductility. When pursuing high strength characteristics in materials, it is often difficult to consider their ductility. Therefore, this study prepared a Ti1400 alloy and in situ synthesized TiC-reinforced (TiC + Ti1400)/TC4 composites using low-energy ball milling and spark plasma sintering technology, followed by hot rolling, to obtain titanium matrix composites with excellent mechanical properties. The Ti1400 alloy bonded well with the matrix, forming uniformly distributed Ti1400 regions within the matrix, and TiC particles were discontinuously distributed around the TiC-lean regions, forming a three-dimensional network structure. The (TiC + Ti1400)/TC4 composites effectively enhanced their yield strength to 1524 MPa by using 3 wt.% of Ti1400 alloy while preserving an impressive elongation of 9%. When the Ti1400 alloy content reaches 20 wt.%, the overall mechanical properties of the composites decrease. A small amount of Ti1400 does not reduce the strength of the composite. On the contrary, it can undergo stress-induced phase transformation during plastic deformation, thereby coordinating deformation, which not only provides higher strain hardening and increases tensile strength but also benefits ductility. Full article

(This article belongs to the Special Issue Materials, Processing, and Post-treatment for Metal-Based Additive Manufacturing)

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Materials, Volume 18, Issue 1 (January-1 2025) – 80 articles

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