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Volume 16
Issue 13
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Materials, Volume 16, Issue 13 (July-1 2023) – 397 articles

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Artificial joints, dental implants, and orthopedic/osseous screws are common applications for titanium, titanium alloys and titanium-based coatings. Bioactive coatings containing titanium oxides and hydroxyapatite (HAP) are obtained through Plasma Electrolytic Oxidation (PEO). Despite the numerous advantages of PEO coatings, the issue of organic contamination often found on bioactive surfaces still needs to be addressed. A coated surface was cleaned using an autoclave, ultraviolet light, radio frequency, air plasma, and UV ozone cleaner. After applying surface cleaning methods, the carbon content decreased from 5.21 at. % to 0.11 at. %. Ozone treatment was the most effective and gentle among the above-mentioned cleaning methods. View this paper

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20 pages, 4093 KiB  
Article
Effect of Blade Geometry on γ′ Lattice Parameter and Primary Orientation of SX Cored Turbine Blades (II)
by Jacek Krawczyk, Włodzimierz Bogdanowicz and Jan Sieniawski
Materials 2023, 16(13), 4892; https://doi.org/10.3390/ma16134892 - 07 Jul 2023
Viewed by 1110
Abstract
The distributions of the lattice parameter of the γ′-phase (aγ′) and angular components of the primary crystal orientation along the lines parallel to the main axis of the single-crystalline CMSX 4-cored turbine blades were studied. The studies were carried out on the regions [...] Read more.
The distributions of the lattice parameter of the γ′-phase (aγ′) and angular components of the primary crystal orientation along the lines parallel to the main axis of the single-crystalline CMSX 4-cored turbine blades were studied. The studies were carried out on the regions of the blades located far from the selector and its continuer extension (CE), positioned asymmetrically relative to the blade’s axis. It was found that, similarly to the regions of the blade located close to the CE (studied in part I), at the level of the blade related to the change of its cross-section, there were correlated local changes in aγ′ and the angular components of the primary crystal orientation representing the bending of the dendrites. However, the correlation was less clear due to the presence of low-angle boundaries (LABs) and the intensification of the consequences of the “fanning effect” in the regions far from the CE. It was found that the range of local changes in aγ′ and the angular components of the primary crystal orientation of the blade regions were influenced by both the distance from the CE and the separation of these regions from the CE by surfaces of the cooling bores. It was found that the deviation angle in the [001] direction from the blade axis increased with an increase in the distance from the CE. Based on the aγ′ changes, differences in the alloying element concentration near the cooling bores were discussed. Full article
(This article belongs to the Section Advanced Materials Characterization)
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43 pages, 23940 KiB  
Review
State of the Art in Development of Heat Exchanger Geometry Optimization and Different Storage Bed Designs of a Metal Hydride Reactor
by Viktor Kudiiarov, Roman Elman, Natalia Pushilina and Nikita Kurdyumov
Materials 2023, 16(13), 4891; https://doi.org/10.3390/ma16134891 - 07 Jul 2023
Cited by 5 | Viewed by 1736
Abstract
The efficient operation of a metal hydride reactor depends on the hydrogen sorption and desorption reaction rate. In this regard, special attention is paid to heat management solutions when designing metal hydride hydrogen storage systems. One of the effective solutions for improving the [...] Read more.
The efficient operation of a metal hydride reactor depends on the hydrogen sorption and desorption reaction rate. In this regard, special attention is paid to heat management solutions when designing metal hydride hydrogen storage systems. One of the effective solutions for improving the heat and mass transfer effect in metal hydride beds is the use of heat exchangers. The design of modern cylindrical-shaped reactors makes it possible to optimize the number of heat exchange elements, design of fins and cooling tubes, filter arrangement and geometrical distribution of metal hydride bed elements. Thus, the development of a metal hydride reactor design with optimal weight and size characteristics, taking into account the efficiency of heat transfer and metal hydride bed design, is the relevant task. This paper discusses the influence of different configurations of heat exchangers and metal hydride bed for modern solid-state hydrogen storage systems. The main advantages and disadvantages of various configurations are considered in terms of heat transfer as well as weight and size characteristics. A comparative analysis of the heat exchangers, fins and other solutions efficiency has been performed, which makes it possible to summarize and facilitate the choice of the reactor configuration in the future. Full article
(This article belongs to the Special Issue Functional Materials for Energy Conversion and Storage (Second Volume))
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16 pages, 6735 KiB  
Article
Microstructural Evolution, Mechanical Properties and Tribological Behavior of B4C-Reinforced Ti In Situ Composites Produced by Laser Powder Bed Fusion
by Jingguang Du, Yaojia Ren, Xinyan Liu, Feng Xu, Xiaoteng Wang, Runhua Zhou, Ian Baker and Hong Wu
Materials 2023, 16(13), 4890; https://doi.org/10.3390/ma16134890 - 07 Jul 2023
Viewed by 1147
Abstract
Based on the advantage of rapid net-shape fabrication, laser powder bed fusion (LPBF) is utilized to process B4C-reinforced Ti composites. The effect of volumetric energy density (VED) on the relative density, microstructural evolution, tensile properties and wear behaviors of [...] Read more.
Based on the advantage of rapid net-shape fabrication, laser powder bed fusion (LPBF) is utilized to process B4C-reinforced Ti composites. The effect of volumetric energy density (VED) on the relative density, microstructural evolution, tensile properties and wear behaviors of B4C-reinforced Ti composites were systematically investigated. The LPBF-ed samples with high relative density (>99%) can be achieved, while the pores and un-melted powders can be observed in the sample owing to the low energy input (33 J/mm3). The additive particulates B4C were transformed into needle-like TiB whiskers with nano-scale while C dissolved in the Ti matrix. Fine-scale grains (<10 μm) with random crystallographic orientation can be achieved and the residual stress shows a downtrend as the VED increases. Through the analysis of the tensile and wear tests, the sample at 61 J/mm3 VED showed a good combination of strength and wear performance, with an ultimate tensile strength of 951 MPa and a wear rate of 3.91 × 10−4 mm3·N−1m−1. The microstructural evolution in VED changes and the corresponding underlying strengthening mechanisms of LPBF-ed Ti + B4C composites are conducted in detail. Full article
(This article belongs to the Special Issue Recent Advances in Metal Powder Based Additive Manufacturing)
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12 pages, 3738 KiB  
Article
Dynamic Characteristic Analysis of a Toothed Electromagnetic Spring Based on the Improved Bouc—Wen Model
by Xiaoyuan Zheng, Cheng Zhang, Yifang Lou, Guangming Xue and Hongbai Bai
Materials 2023, 16(13), 4889; https://doi.org/10.3390/ma16134889 - 07 Jul 2023
Viewed by 847
Abstract
Electromagnetic spring active isolators have attracted extensive attention in recent years. The standard Bouc–Wen model is widely used to describe hysteretic behavior but cannot accurately describe asymmetric behavior. The standard Bouc–Wen model is improved to better describe the dynamic characteristic of a toothed [...] Read more.
Electromagnetic spring active isolators have attracted extensive attention in recent years. The standard Bouc–Wen model is widely used to describe hysteretic behavior but cannot accurately describe asymmetric behavior. The standard Bouc–Wen model is improved to better describe the dynamic characteristic of a toothed electromagnetic spring. The hysteresis model of toothed electromagnetic spring is established by adding mass, damping, and asymmetric correction terms with direction. Subsequently, the particle swarm optimization algorithm is used to identify the parameters of the established model, and the results are compared with those obtained from the experiment. The results show that the current has a significant impact on the dynamic curve. When the current increases from 0.5 A to 2.0 A, the electromagnetic force sharply increases from 49 N to 534 N. Under different excitations and currents, the residual points predicted by the model proposed in this work fall basically in the horizontal band region of −20–20 N (for an applied current of 1.0 A) and −40–80 N (for an application of 4.5 mm/s). Furthermore, the maximum relative error of the model is 12.75%. The R2 of the model is higher than 0.98 and the highest value is 0.9993, proving the accuracy of the established model. Full article
(This article belongs to the Special Issue Dynamic Behavior of Advanced Materials and Structures)
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16 pages, 11512 KiB  
Article
The Evolution of Insulation Performance of Fiber-Reinforced Silica Aerogel after High-Temperature Treatment
by Rui Gao, Zhangjian Zhou, Hongbo Zhang, Xiaoge Zhang and Yuming Wu
Materials 2023, 16(13), 4888; https://doi.org/10.3390/ma16134888 - 07 Jul 2023
Cited by 2 | Viewed by 1055
Abstract
Fiber-reinforced silica aerogel blankets (FRABs) are an important high-temperature thermal insulation material for industry applications that have emerged in recent years. In order to better understand the performance evolution of FRABs at high temperatures, the effect of heat treatment at different temperatures on [...] Read more.
Fiber-reinforced silica aerogel blankets (FRABs) are an important high-temperature thermal insulation material for industry applications that have emerged in recent years. In order to better understand the performance evolution of FRABs at high temperatures, the effect of heat treatment at different temperatures on the performance of FRABs as well as their base material, hydrophobic silica aerogel powder and glass wool, was investigated. The property evolution of the hydrophobic silica aerogel powder showed two stages with an increase in thermal treatment temperatures. The skeleton structure of the aerogel remained unchanged, but the residual organic chemicals, such as hydrophobic groups, were decomposed when the heat treatment temperature was lower than 400 °C. Above 400 °C, the skeleton began to shrink with the increase in temperature, which led to an increase in thermal conductivity. The structure and room-temperature thermal conductivity of the glass wool blanket were less affected by a heat treatment temperature under 600 °C. Therefore, the performance degradation of FRABs at high temperatures is mainly due to the change in the aerogel powder. The insulation performance of the glass wool and FRAB at high temperatures was studied using a heating table which was designed to simulate working conditions. The energy savings of using FRABs instead of glass fiber were calculated and are discussed here. Full article
(This article belongs to the Special Issue Qualitative-Environmental Aspects to Improve Materials and Processes of Their Formation)
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17 pages, 2019 KiB  
Article
Stability Analysis of Shear Deformable Inhomogeneous Nanocomposite Cylindrical Shells under Hydrostatic Pressure in Thermal Environment
by Abdullah H. Sofiyev and Nicholas Fantuzzi
Materials 2023, 16(13), 4887; https://doi.org/10.3390/ma16134887 - 07 Jul 2023
Cited by 6 | Viewed by 688
Abstract
In this study, the stability of inhomogeneous nanocomposite cylindrical shells (INCCSs) under hydrostatic pressure in a thermal environment is presented. The effective material properties of the inhomogeneous nanocomposite cylindrical shell are modeled on the basis of the extended mixture rule. Based on the [...] Read more.
In this study, the stability of inhomogeneous nanocomposite cylindrical shells (INCCSs) under hydrostatic pressure in a thermal environment is presented. The effective material properties of the inhomogeneous nanocomposite cylindrical shell are modeled on the basis of the extended mixture rule. Based on the effective material properties, the fundamental relations and stability equations are derived for thermal environments. In this process, the first-order shear deformation theory (FSDT) for the homogeneous orthotropic shell is generalized to the inhomogeneous shell theory. This is accomplished using the modified Donnell-type shell theory. The analytical expressions are obtained for hydrostatic buckling pressure of INCCSs in the framework of FSDT and classical shell theory (CST) by obtaining a solution based on Galerkin’s procedure. The numerical examples presented include both comparisons and original results. The last section shows the influences of carbon nanotube (CNT) models, volume fraction, and shell characteristics on the hydrostatic buckling pressure in the thermal environment. Full article
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20 pages, 15933 KiB  
Article
Study on Morphology, Microstructure and Properties of 6063-T6 Aluminum Alloy Joints in MIG Welding
by Shuwan Cui, Yunhe Yu, Rong Ma, Fuyuan Tian and Shuwen Pang
Materials 2023, 16(13), 4886; https://doi.org/10.3390/ma16134886 - 07 Jul 2023
Cited by 2 | Viewed by 1044
Abstract
In this paper, a metal inert gas (MIG) shielded welding method was used for high-quality welding of 6063-T6 aluminum alloy sheet with a thickness of 2.5 mm. The welding process of MIG welding was accurately simulated and the welding temperature field and thermal [...] Read more.
In this paper, a metal inert gas (MIG) shielded welding method was used for high-quality welding of 6063-T6 aluminum alloy sheet with a thickness of 2.5 mm. The welding process of MIG welding was accurately simulated and the welding temperature field and thermal cycle curve were calculated using a combination of Gaussian body heat source and double ellipsoidal heat source. As the welding current increased from 75 A to 90 A, the reinforcing phase precipitated under the microstructure of the joint gradually became larger and re-solidified into the body, resulting in a reduction in mechanical properties. When the welding current is 85 A, the pitting resistance of weld forming and weld area reaches its optimum. At this time, the tensile strength of the joint is up to 110.9 MPa, the elongation is up to 16.3% and the Vickers Microhardness is up to 46.9 HV. Full article
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15 pages, 6299 KiB  
Article
Synthesis and Characterization of Pyridine Acetohydrazide Derivative for Antimicrobial Cotton Fabric
by Saeed El-Sayed Saeed, Meaad Aldubayyan, Ahmed N. Al-Hakimi and Marwa M. Abd El-Hady
Materials 2023, 16(13), 4885; https://doi.org/10.3390/ma16134885 - 07 Jul 2023
Viewed by 807
Abstract
An increase in textile resistance to antimicrobial agents has posed a pressing need for the development of new antimicrobials. Therefore, the antimicrobial characteristics of thiophene and pyridine acetohydrazide derivatives have been developed as novel textile-modified complexes exhibiting antibacterial agents. Synthesis and characterization of [...] Read more.
An increase in textile resistance to antimicrobial agents has posed a pressing need for the development of new antimicrobials. Therefore, the antimicrobial characteristics of thiophene and pyridine acetohydrazide derivatives have been developed as novel textile-modified complexes exhibiting antibacterial agents. Synthesis and characterization of pyridyl-thienyl acetohydrazide derivative (AHZ) using NMR (13C and 1H) and FTIR. Modification of cotton fabric (CF) with acetohydrazide (AHZ) and metal chlorides of divalent Cr, Mn, Co, Ni, Cu, and Zn and trivalent Fe, and Cr. SEM-EDX and Fourier-transform infrared were utilized to characterize cellulose-based cotton fabric (CF) attached to AHZ and their metal (M) complexes. Antimicrobial activity was examined against two types of bacteria, namely S. aureus and E. coli, and two types of fungi, namely C. albicans and A. flavus. All modified samples exhibited higher efficiency towards bacterial strains than fungal strains. In addition, cellulose modified with Ni (II) confers the most antibacterial protection efficiency. Full article
(This article belongs to the Special Issue Advances in Multifunctional Textiles: Materials, Technologies and Production Processes)
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25 pages, 2536 KiB  
Article
High-Efficiency Removal of Lead and Nickel Using Four Inert Dry Biomasses: Insights into the Adsorption Mechanisms
by Candelaria Tejada-Tovar, Angel Villabona-Ortíz and Ángel Darío González-Delgado
Materials 2023, 16(13), 4884; https://doi.org/10.3390/ma16134884 - 07 Jul 2023
Cited by 2 | Viewed by 818
Abstract
In this study, inert dry bioadsorbents prepared from corn cob residues (CCR), cocoa husk (CH), plantain peels (PP), and cassava peels (CP) were used as adsorbents of heavy metal ions (Pb2+ and Ni2+) in single-batch adsorption experiments from synthetic aqueous [...] Read more.
In this study, inert dry bioadsorbents prepared from corn cob residues (CCR), cocoa husk (CH), plantain peels (PP), and cassava peels (CP) were used as adsorbents of heavy metal ions (Pb2+ and Ni2+) in single-batch adsorption experiments from synthetic aqueous solutions. The physicochemical properties of the bioadsorbents and the adsorption mechanisms were evaluated using different experimental techniques. The results showed that electrostatic attraction, cation exchange, and surface complexation were the main mechanisms involved in the adsorption of metals onto the evaluated bioadsorbents. The percentage removal of Pb2+ and Ni2+ increased with higher adsorbent dosage, with Pb2+ exhibiting greater biosorption capacity than Ni2+. The bioadsorbents showed promising potential for adsorbing Pb2+ with monolayer adsorption capacities of 699.267, 568.794, 101.535, and 116.820 mg/g when using PP, CCR, CH, and CP, respectively. For Ni2+, Langmuir’s parameter had values of 10.402, 26.984, 18.883, and 21.615, respectively, for PP, CCR, CH, and CP. Kinetics data fitted by the pseudo-second-order model revealed that the adsorption rate follows this order: CH > CP > CCR > PP for Pb2+, and CH > CCR > PP > CP for Ni2+. The adsorption mechanism was found to be controlled by ion exchange and precipitation. These findings suggest that the dry raw biomasses of corn cob residues, cocoa husk, cassava, and plantain peels can effectively remove lead and nickel, but further research is needed to explore their application in industrial-scale and continuous systems. Full article
(This article belongs to the Special Issue Green Biosorbents: Synthesis, Characterization and Application for the Removal of Contaminants from Water and Soil)
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24 pages, 9643 KiB  
Article
Physical, Mechanical, and Microstructure Characteristics of Ultra-High-Performance Concrete Containing Lightweight Aggregates
by Aref A. Abadel
Materials 2023, 16(13), 4883; https://doi.org/10.3390/ma16134883 - 07 Jul 2023
Cited by 6 | Viewed by 1309
Abstract
This study explores and enhances the resistance of an ultra-high-performance concrete (UHPC) to explosive spalling under elevated temperatures. This study investigates the impact of lightweight aggregates (LWAs) on the mechanical and microstructural properties of the UHPC. Various UHPC specimens were created by replacing [...] Read more.
This study explores and enhances the resistance of an ultra-high-performance concrete (UHPC) to explosive spalling under elevated temperatures. This study investigates the impact of lightweight aggregates (LWAs) on the mechanical and microstructural properties of the UHPC. Various UHPC specimens were created by replacing silica sand with LWAs in percentages ranging from 0% to 30%. The evaluation of these specimens involved assessing their compressive and flexural strengths, density, mass loss, shrinkage, porosity, and microstructural characteristics using scanning electron microscopy (SEM). This study provides valuable insights by analyzing the influence of lightweight aggregates on the strength, durability, and microstructure of UHPC. The results reveal that incorporating LWAs in the UHPC improved its flowability while decreasing its density, as the percentage of LWAs increased from 5% to 30%. Including 30% LWA resulted in a mass loss of 4.8% at 300 °C, which reduced the compressive and flexural strengths across all curing durations. However, the UHPC samples subjected to higher temperatures displayed higher strength than those exposed to ambient conditions. The microstructure analysis demonstrated that the UHPC specimens with 30% LWA exhibited increased density due to continuous hydration from the water in the lightweight aggregate. The pore size distribution graph indicated that incorporating more of the LWA increased porosity, although the returns diminished beyond a certain point. Overall, these findings offer valuable insights into the influence of lightweight aggregates on the physical and strength characteristics of UHPC. This research holds significant implications for developing high-performance, lightweight concrete materials. Full article
(This article belongs to the Special Issue Ultra High Performance Concrete (UHPC): Current and Future Research)
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14 pages, 4324 KiB  
Article
Electrospun Fibers of Biocompatible and Biodegradable Polyesters, Poly(Ethylene Oxide) and Beeswax with Anti-Bacterial and Anti-Fungal Activities
by Selin Kyuchyuk, Dilyana Paneva, Nevena Manolova, Iliya Rashkov, Daniela Karashanova, Mladen Naydenov and Nadya Markova
Materials 2023, 16(13), 4882; https://doi.org/10.3390/ma16134882 - 07 Jul 2023
Viewed by 792
Abstract
Fibrous materials composed of core–sheath fibers from poly(ethylene oxide) (PEO), beeswax (BW) and 5-nitro-8-hydroxyquinoline (NQ) were prepared via the self-organization of PEO and BW during the single-spinneret electrospinning of a homogeneous blend solution of the partners. Additionally, the application of the same approach [...] Read more.
Fibrous materials composed of core–sheath fibers from poly(ethylene oxide) (PEO), beeswax (BW) and 5-nitro-8-hydroxyquinoline (NQ) were prepared via the self-organization of PEO and BW during the single-spinneret electrospinning of a homogeneous blend solution of the partners. Additionally, the application of the same approach enabled the preparation of fibrous materials composed of core–double sheath fibers from PEO, poly(L-lactide) (PLA) and NQ or 5-chloro-7-iodo-8-hydroxyquinoline (CQ), as well as from PEO, poly(ε-caprolactone) (PCL) and NQ. The consecutive selective extraction of BW and of the polyester with hexane and tetrahydrofuran, respectively, evidenced that core–double sheath fibers from PEO/polyester/BW/drug consisted of a PEO core, a polyester inner sheath and a BW outer sheath. In order to evaluate the possibility of the application of fibrous materials from PEO/BW/NQ, PEO/PLA/BW/NQ, PEO/PCL/BW/NQ and PEO/PLA/BW/CQ for plant protection, microbiological studies were performed using both phytopathogenic microorganisms (Pseudomonas corrugata, Fusarium graminearum and Fusarium avenaceum) and beneficial microorganisms (Pseudomonas chlororaphis, Bacillus amyloliquefaciens and Trichoderma asperellum). It was found that the fibrous materials had anti-bacterial and anti-fungal activity against both phytopathogenic and beneficial microorganisms. This is the first report on the activity of fibrous materials loaded with 8-hydroxyquinoline derivatives not only against phytopathogenic but also against beneficial microorganisms that are of importance in agriculture. Full article
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17 pages, 4435 KiB  
Article
Study on Adhesion Performance and Aging Strength Degradation Mechanism of SBS Modified Asphalt with Different Anti-Aging Additive
by Chuanyi Zhuang, Hao Guo, Fengxiang Li, Yan Hao, Kun Chen, Gen Li and Yali Ye
Materials 2023, 16(13), 4881; https://doi.org/10.3390/ma16134881 - 07 Jul 2023
Cited by 2 | Viewed by 865
Abstract
After aging, the adhesiveness of asphalt deteriorates, leading to a reduction in the durability of asphalt mixtures and affecting the service life of asphalt pavements. To enhance the anti-aging performance of asphalt, this study employed the method of melt blending to prepare three [...] Read more.
After aging, the adhesiveness of asphalt deteriorates, leading to a reduction in the durability of asphalt mixtures and affecting the service life of asphalt pavements. To enhance the anti-aging performance of asphalt, this study employed the method of melt blending to prepare three types of modified asphalt: graphene/SBS modified asphalt (G/SBSMA), crumb rubber/SBS modified asphalt (CR/SBSMA), and petroleum resin/SBS modified asphalt (PR/SBSMA). Different dosages of the three types of modified asphalt were tested for changes in conventional performance indicators. The optimal dosages of graphene, crumb rubber, and C9 petroleum resin were determined to be 2%, 15%, and 5%, respectively. Based on the theory of surface free energy, the effects of anti-aging agents on the microscopic properties of SBS modified asphalt before and after aging were analyzed using the three-liquid method. The mechanisms of strength attenuation at the asphalt–aggregate interface under water exposure and aging were revealed. The results showed that with the increase of aging gradient, the asphalt-aggregate biphasic system became more active. The cohesive energy and peel energy of SBS modified asphalt increased continuously, while the adhesive energy decreased continuously, leading to a decrease in the energy ratio parameter. Resin-based anti-aging agents exhibited the most significant improvement in asphalt adhesion performance, while graphene demonstrated a more stable enhancement in asphalt’s water stability during the aging stage. Full article
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13 pages, 5148 KiB  
Article
Experimental Study on the Fracture Toughness of Bamboo Scrimber
by Kairan Zhang, Yubo Hou, Yubin Lu and Mingtao Wang
Materials 2023, 16(13), 4880; https://doi.org/10.3390/ma16134880 - 07 Jul 2023
Cited by 3 | Viewed by 870
Abstract
In the past decade, bamboo scrimber has developed rapidly in the field of building materials due to its excellent mechanical properties, such as high toughness and high tensile strength. However, when the applied stress exceeds the ultimate strength limit of bamboo scrimber, cracks [...] Read more.
In the past decade, bamboo scrimber has developed rapidly in the field of building materials due to its excellent mechanical properties, such as high toughness and high tensile strength. However, when the applied stress exceeds the ultimate strength limit of bamboo scrimber, cracks occur, which affects the performance of bamboo scrimber in structural applications. Due to the propensity of cracks to propagate, it reduces the load-bearing capacity of the bamboo scrimber material. Therefore, research on the fracture toughness of bamboo scrimber contributes to determining the material’s load-bearing capacity and failure mechanisms, enabling its widespread application in engineering failure analysis. The fracture toughness of bamboo scrimber was studied via the single-edge notched beam (SENB) experiment and compact compression (CC) method. Nine groups of longitudinal and transverse samples were selected for experimental investigation. The fracture toughness of longitudinal bamboo scrimber under tensile and compressive loadings was 3.59 MPa·m1/2 and 2.39 MPa·m1/2, respectively. In addition, the fracture toughness of transverse bamboo scrimber under tensile and compressive conditions was 0.38 MPa·m1/2 and 1.79 MPa·m1/2, respectively. The results show that, for this material, there was a significant distinction between longitudinal and transverse. Subsequently, three-point bending tests and simulations were studied. The results show that the failure mode and the force–displacement curve of the numerical simulation were highly consistent compared with the experimental results. It could verify the correctness of the test parameters. Finally, the flexural strength of bamboo scrimber was calculated to be as high as 143.16 MPa. This paper provides data accumulation for the numerical simulation of bamboo scrimber, which can further promote the development of bamboo scrimber parameters in all aspects of the application. Full article
(This article belongs to the Section Construction and Building Materials)
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17 pages, 8752 KiB  
Article
Study on Elastic Mixed Mode Fracture Behavior and II-III Coupling Effect
by Xinting Miao, Jinbo Zhang, Haisheng Hong, Jian Peng, Binbin Zhou and Qianqian Li
Materials 2023, 16(13), 4879; https://doi.org/10.3390/ma16134879 - 07 Jul 2023
Viewed by 857
Abstract
Mixed mode fracture is a widely studied topic, while the coupling effects of mixed mode cracking are unclear. In this paper, elastic fracture behaviors and the coupling effects of the mixed mode cracks are studied in detail based on the finite element method, [...] Read more.
Mixed mode fracture is a widely studied topic, while the coupling effects of mixed mode cracking are unclear. In this paper, elastic fracture behaviors and the coupling effects of the mixed mode cracks are studied in detail based on the finite element method, experimental study and linear elastic fracture mechanics. Results show that there always exist II-III coupling effects at the crack tips of mixed mode cracks, which have many effects on the crack tip field and crack propagation behavior. It is found that a mode II component at the tip of a mixed mode crack is the main reason for crack deflection, while the mode III components show no effect. For any mixed mode crack, mode II components at the crack tip can be divided as that by mode II loading which causes plane crack propagation, and by the coupling effect which causes spatial crack propagation. On this basis, a new fracture criterion suitable for any mixed mode crack is proposed, combined with the coupling effect and the linear elastic superposition principle. The research in this paper provides a solution to the problem of an II-III coupling effect in mixed mode fracture research and further promotes the development of fracture mechanics. Full article
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13 pages, 3918 KiB  
Article
Three-Dimensional Macroporous rGO-Aerogel-Based Composite Phase-Change Materials with High Thermal Storage Capacity and Enhanced Thermal Conductivity
by Zhang Tao, Wei He, Xiaoliang Xu, Jianzhong Fan, Zhifeng Zhang, Ziyue Yang, Yanqiang Liu, Heng Ma, Miao Qian and Mu Yang
Materials 2023, 16(13), 4878; https://doi.org/10.3390/ma16134878 - 07 Jul 2023
Cited by 1 | Viewed by 946
Abstract
Three-dimensional porous network encapsulation strategy is an effective means to obtain composite phase-change materials (PCMs) with high heat storage capacity and enhanced thermal conductivity. Herein, macroporous reduced graphene oxide (rGO) aerogels with adjustable pore size are prepared by the emulsion template method and [...] Read more.
Three-dimensional porous network encapsulation strategy is an effective means to obtain composite phase-change materials (PCMs) with high heat storage capacity and enhanced thermal conductivity. Herein, macroporous reduced graphene oxide (rGO) aerogels with adjustable pore size are prepared by the emulsion template method and hydrothermal reduction process. Further, the shape-stabilized rGO-aerogel-based composite PCMs are constructed after the combination of 3D porous rGO supports and paraffin wax (PW) through vacuum melting infiltration. By regulating the pore structure of the rGO aerogel network, the rGO-based composite PCMs achieve excellent energy storage properties with a phase-change enthalpy of 179.94 J/g for the loading amount of 95.61 wt% and an obvious enhancement in thermal conductivity of 0.412 W/m−1·K−1, which is 54.89% higher than pristine PW and enduring thermal cycling stability. The obtained macroporous rGO-aerogel-based composite PCMs with high thermal storage and heat transfer performance effectively broaden the application of PCMs in the field of thermal energy storage. Full article
(This article belongs to the Special Issue Advanced Materials and Technologies for Thermal Energy Storage)
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19 pages, 5633 KiB  
Article
Influence of Fiber Orientation on the Water and Ions Transportation of Engineered Cementitious Composite (ECC)
by Abdullah M. Tawfek, Zhi Ge, Jian Li, Kangkang Zhang, Nengdong Jiang, Yingxuan Shao, Yifeng Ling and Branko Šavija
Materials 2023, 16(13), 4877; https://doi.org/10.3390/ma16134877 - 07 Jul 2023
Viewed by 952
Abstract
An engineered cementitious composite (ECC) belongs to a type of high-performance fiber-reinforced materials. Fiber alignment causes the anisotropy of such materials. Herein, the influence of the fiber orientation on water and ion penetration into an ECC was studied. Fiber alignment was achieved using [...] Read more.
An engineered cementitious composite (ECC) belongs to a type of high-performance fiber-reinforced materials. Fiber alignment causes the anisotropy of such materials. Herein, the influence of the fiber orientation on water and ion penetration into an ECC was studied. Fiber alignment was achieved using an extrusion approach. Water absorption, sorptivity, chloride penetration resistance, sulfate attack resistance, and freezing–thawing resistance of specimens with fiber aligned horizontally (AH), vertically (AV), and randomly (R), corresponding to the direction of the exposure surface that was studied. The results showed that fibers oriented perpendicular to the water path delayed water migration into the ECC matrix. The sorptivity was significantly affected by the fiber direction. The sorptivity of the AH specimens was 35% and 13% lower than that of the AV and R specimens, respectively. After 180 days of exposure, the chloride penetration depth of the AH specimens was 5.7 mm, which is 13.6% and 20.8% lower than that of the AV and R specimens, respectively. The sulfate ingress profile indicates that the fiber–matrix interface oriented perpendicular to the penetration path can effectively delay sulfate migration. The fiber orientation also influences the compressive strength gain under immersion conditions (Na2SO4 solution, Na2SO4 + NaCl solution, and water). Compared with the AH and R specimens, the AV specimens are more sensitive to the immersion condition. In contrast, the fiber orientation has no significant effect on ECC specimens under freeze–thaw cycles. These findings indicate that controlling the fiber alignment and orientation in an ECC can improve its durability under certain exposure conditions. Full article
(This article belongs to the Special Issue Advances in Preparation and Characterization of High-Performance Cement-Based Structural Materials)
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26 pages, 11506 KiB  
Article
Silver Vapor Supersonic Jets: Expansion Dynamics, Cluster Formation, and Film Deposition
by Alexander V. Bulgakov, Nikolay Y. Bykov, Alexey I. Safonov, Yuri G. Shukhov and Sergey V. Starinskiy
Materials 2023, 16(13), 4876; https://doi.org/10.3390/ma16134876 - 07 Jul 2023
Cited by 1 | Viewed by 908
Abstract
Supersonic jets of metal vapors with carrier gas are promising for producing nanostructured metal films at relatively low source temperatures and high deposition rates. However, the effects of the carrier gas on the jet composition and expansion dynamics, as well as on film [...] Read more.
Supersonic jets of metal vapors with carrier gas are promising for producing nanostructured metal films at relatively low source temperatures and high deposition rates. However, the effects of the carrier gas on the jet composition and expansion dynamics, as well as on film properties, remain virtually unexplored. In this work, the free-jet expansion of a mixture of silver vapor with helium in a rarefied regime at an initial temperature of 1373 K is investigated through mass spectrometry and direct-simulation Monte Carlo methods. Introducing the carrier gas into the source is found to result in a transition from a collisionless to a collision-dominated expansion regime and dramatic changes in the Ag jet, which becomes denser, faster, and more forward-directed. The changes are shown to be favorable for the formation of small Ag clusters and film deposition. At a fairly high helium flow, silver Ag2 dimers are observed in the jet, both in the experiment and the simulations, with a mole fraction reaching 0.1%. The terminal velocities of silver atoms and dimers are nearly identical, indicating that the clusters are likely formed due to the condensation of silver vapor in the expanding jet. A high potential of supersonic Ag-He jets for the deposition of nanostructured silver films is demonstrated. The deposited jet Ag2 dimers appear to serve as nucleation centers and, thus, allow for controlling the size of the produced surface nanostructures. Full article
(This article belongs to the Special Issue Advances in Coatings Prepared by Deposition: Microstructure, Properties and Applications)
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17 pages, 3028 KiB  
Article
Differential Energy Criterion for Brittle Fracture: Conceptualization and Application to the Analysis of Axial and Lateral Deformation in Uniaxial Compression of Rocks
by Vitali Shekov and Gennady Kolesnikov
Materials 2023, 16(13), 4875; https://doi.org/10.3390/ma16134875 - 07 Jul 2023
Cited by 2 | Viewed by 2012
Abstract
This paper discusses modeling the behavior and prediction of fracture of brittle materials. Numerous publications show that progress in this area is characterized by the emergence of a number of new models that meet the requirements of the mining industry, construction and other [...] Read more.
This paper discusses modeling the behavior and prediction of fracture of brittle materials. Numerous publications show that progress in this area is characterized by the emergence of a number of new models that meet the requirements of the mining industry, construction and other engineering practices. The authors focus only on one class of models, paying special attention to the compromise between simplicity of solution and versatility of the model. A new version of the model is proposed, taking into account the advantages of previous models. We present a differential energy criterion for brittle fracture substantiated, according to which, fracture occurs at a certain ratio of dissipated and stored (elastic) energy. Fracture is considered as the end of the deformation process with a virtual transformation of the initial material almost without cracks into a real material with cracks. The highest and lowest elastic moduli are analytically determined, respectively, on the ascending and descending branches of the stress–strain curve. A graphical version of the algorithm for determining the brittle fracture point on the post-peak branch of the stress–strain curve is proposed. The modeling results are consistent with the experimental data known from the literature. Full article
(This article belongs to the Section Construction and Building Materials)
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17 pages, 6420 KiB  
Review
Novel Amorphous-Wollastonitic Low-Calcium Hydraulic Binders: A State-of-the-Art Review
by Mónica Antunes, Rodrigo L. Santos, Ricardo B. Horta and Rogério Colaço
Materials 2023, 16(13), 4874; https://doi.org/10.3390/ma16134874 - 07 Jul 2023
Cited by 1 | Viewed by 666
Abstract
Because of the severe environmental impact of the CO2 emissions associated with the production of ordinary Portland cement (OPC) and the increasing demand for this commodity material, the development of alternative products has become a global concern. One alternative to OPC, or [...] Read more.
Because of the severe environmental impact of the CO2 emissions associated with the production of ordinary Portland cement (OPC) and the increasing demand for this commodity material, the development of alternative products has become a global concern. One alternative to OPC, or alitic-based clinkers, are amorphous-wollastonitic low-calcium hydraulic binders (AWLCs). This new class of hydraulic binders, described in the literature for the first time in 2015, may significantly reduce the CO2 emissions associated with its production, resulting from its lower calcium content, but also from the fact that its production technology can be fully electrified. In this paper, a state-of-the-art review is presented, providing a comprehensive description of the latest research, summarizing both the physicochemical and mechanical characteristics of this type of hydraulic binder, as well as possible routes for its production at an industrial scale. Full article
(This article belongs to the Collection Advanced Civil Engineering Materials: From Synthesis to Application)
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9 pages, 3214 KiB  
Communication
Degradation of Polymethylmethacrylate (PMMA) Bioreactors Used for Algal Cultivation
by Ewa Borucinska, Przemyslaw Zamojski, Wojciech Grodzki, Urszula Blaszczak, Izabela Zglobicka, Marcin Zielinski and Krzysztof J. Kurzydlowski
Materials 2023, 16(13), 4873; https://doi.org/10.3390/ma16134873 - 07 Jul 2023
Viewed by 699
Abstract
This paper depicts characteristics of degradation of walls of bioreactors made of polymethylmethacrylate (PMMA) which was used to culture algae. The degradation processes take place stimulated by lighting of external surface and interaction with cultured species on internal surface. Results presented are representative [...] Read more.
This paper depicts characteristics of degradation of walls of bioreactors made of polymethylmethacrylate (PMMA) which was used to culture algae. The degradation processes take place stimulated by lighting of external surface and interaction with cultured species on internal surface. Results presented are representative for degradation of a bioreactor tube after the 4-year cultivation of Chlorella sp. Microscopic observations, roughness and transmission tests showed that changes have occurred on the inner surface. The result of use is a decrease in transmission and an increase in roughness. Microscopic observations showed that particles remained after culture, especially in cracks. Full article
(This article belongs to the Section Polymeric Materials)
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20 pages, 2592 KiB  
Article
A Comparison of Capacitive Deionization and Membrane Capacitive Deionization Using Novel Fabricated Ion Exchange Membranes
by Mahmoud M. Elewa, Mervette El Batouti and Nouf F. Al-Harby
Materials 2023, 16(13), 4872; https://doi.org/10.3390/ma16134872 - 07 Jul 2023
Cited by 3 | Viewed by 1401
Abstract
Another technique for desalination, known as membrane capacitive deionization (MCDI), has been investigated as an alternative. This approach has the potential to lower the voltage that is required, in addition to improving the ability to renew the electrodes. In this study, the desalination [...] Read more.
Another technique for desalination, known as membrane capacitive deionization (MCDI), has been investigated as an alternative. This approach has the potential to lower the voltage that is required, in addition to improving the ability to renew the electrodes. In this study, the desalination effectiveness of capacitive deionization (CDI) was compared to that of MCDI, employing newly produced cellulose acetate ion exchange membranes (IEMs), which were utilized for the very first time in MCDI. As expected, the salt adsorption and charge efficiency of MCDI were shown to be higher than those of CDI. Despite this, the unique electrosorption behavior of the former reveals that ion transport via the IEMs is a crucial rate-controlling step in the desalination process. We monitored the concentration of salt in the CDI and MCDI effluent streams, but we also evaluated the pH of the effluent stream in each of these systems and investigated the factors that may have caused these shifts. The significant change in pH that takes place during one adsorption and desorption cycle in CDI (pH range: 2.3–11.6) may cause problems in feed water that already contains components that are prone to scaling. In the case of MCDI, the fall in pH was only slightly more noticeable. Based on these findings, it appears that CDI and MCDI are promising new desalination techniques that has the potential to be more ecologically friendly and efficient than conventional methods of desalination. MCDI has some advantages over CDI in its higher salt removal efficiency, faster regeneration, and longer lifetime, but it is also more expensive and complex. The best choice for a particular application will depend on the specific requirements. Full article
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16 pages, 4351 KiB  
Review
The Recent Progress of Pitch Nanoengineering to Obtain the Carbon Anode for High-Performance Sodium Ion Batteries
by Wen-Sheng Du, Chen Sun and Qiang Sun
Materials 2023, 16(13), 4871; https://doi.org/10.3390/ma16134871 - 07 Jul 2023
Cited by 6 | Viewed by 2330
Abstract
As an anode material for sodium ion batteries (SIBs), carbon materials have attracted people’s interest because of their abundant resources, good structural stability and low cost. Among most carbon precursors, pitch is viewed as a promising one because of a higher carbon content, [...] Read more.
As an anode material for sodium ion batteries (SIBs), carbon materials have attracted people’s interest because of their abundant resources, good structural stability and low cost. Among most carbon precursors, pitch is viewed as a promising one because of a higher carbon content, good oxidation reversibility and low cost. However, the pitch-based carbon obtained with direct pyrolysis of pitch displays a high degree of graphitization and small layer spacing, which is unfavorable for the storage of sodium ions. In recent years, with the aid of the development of the nanoengineering process, the storage of sodium ions with pitch-based carbon has been drastically improved. This review article summarizes the recent progress of pitch nanoengineering to obtain the carbon anode for high-performance SIBs, including porous structure adjustment, heteroatom doping, co-carbonization and pre-oxidation. In addition, the merits and demerits of a variety of nanoengineering processes are discussed, and future research directions of pitch-based carbon are prospected. Full article
(This article belongs to the Special Issue Development of Novel Electrode and Electrolyte Materials for Lithium and Sodium Ion Batteries)
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15 pages, 3096 KiB  
Article
Effect of Reducing the Size and Number of Faces of Polyhedral Specimen on Wood Characterization by Ultrasound
by Cinthya Bertoldo, Geise Aparecida Pereira and Raquel Gonçalves
Materials 2023, 16(13), 4870; https://doi.org/10.3390/ma16134870 - 07 Jul 2023
Viewed by 627
Abstract
The complete characterization of wood, with the determination of the 12 elastic constants that represent its orthotropy, is greatly relevant in applications employing structural calculation software programs. Ultrasound allows for such characterization with relative simplicity when compared to other methods. The polyhedron is [...] Read more.
The complete characterization of wood, with the determination of the 12 elastic constants that represent its orthotropy, is greatly relevant in applications employing structural calculation software programs. Ultrasound allows for such characterization with relative simplicity when compared to other methods. The polyhedron is considered the most appropriate specimen format for allowing the 12 constants to be calculated with a single specimen, and the traditionally used one is the 26-sided polyhedron, which, to be produced manually with more precision in directing the main directions of the wood, needs larger faces. The accuracy of this technique tends to be reduced when increasing the growth rings’ inclination since the waves deviate from the main directions of orthotropy. This research aimed to verify whether it is possible to reduce the polyhedra dimension without affecting the results of the elastic parameters obtained in wood characterization by ultrasound. The results indicate that the dimension of the polyhedron can be reduced without prejudice to the results of the elastic parameters obtained by the ultrasound test and that, in the manual production process of the specimen, the best way to make this reduction is to eliminate the faces unused in the test, changing the polyhedron to 18 faces instead of 26. Reducing the number of faces simplifies the manufacturing process and thus increases the possibility of producing specimens with straighter growth rings and better-directed symmetry axes. Full article
(This article belongs to the Special Issue Sustainable Lignocellulosic Materials)
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16 pages, 4296 KiB  
Article
Effect of Cellulose-Based Bioplastics on Current LDPE Recycling
by Giovanni Gadaleta, Sabino De Gisi, Andrea Sorrentino, Luigi Sorrentino, Michele Notarnicola, Kerstin Kuchta, Caterina Picuno and Maria Oliviero
Materials 2023, 16(13), 4869; https://doi.org/10.3390/ma16134869 - 07 Jul 2023
Cited by 2 | Viewed by 1692
Abstract
The increased use of bioplastics in the market has led to their presence in municipal solid waste streams alongside traditional fossil-based polymers, particularly low-density polyethylene (LDPE), which bioplastics often end up mixed with. This study aimed to assess the impact of cellulose acetate [...] Read more.
The increased use of bioplastics in the market has led to their presence in municipal solid waste streams alongside traditional fossil-based polymers, particularly low-density polyethylene (LDPE), which bioplastics often end up mixed with. This study aimed to assess the impact of cellulose acetate plasticized with triacetin (CAT) on the mechanical recycling of LDPE. LDPE–CAT blends with varying CAT content (0%, 1%, 5%, 7.5%, and 10% by weight) were prepared by melt extrusion and analyzed using scanning electron microscopy, Fourier-transform infrared spectroscopy, thermal analysis (thermogravimetric and differential scanning calorimetry), dynamic rheological measurements, and tensile tests. The results indicate that the presence of CAT does not significantly affect the chemical, thermal, and rheological properties of LDPE, and the addition of CAT at different levels does not promote LDPE degradation under typical processing conditions. However, the addition of CAT negatively impacts the processability and mechanical behavior of LDPE, resulting in the reduced quality of the recycled material. Thus, the presence of cellulose-based bioplastics in LDPE recycling streams should be avoided, and a specific sorting stream for bioplastics should be established. Full article
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18 pages, 3859 KiB  
Article
Proposition of New Testing Procedure for the Mechanical Properties of Bulk-Fill Materials
by Matea Macan, Ana Marošević, Bruno Špiljak, Luka Šimunović, Matej Par, Danijela Marovic, Danijela Juric-Kacunic and Zrinka Tarle
Materials 2023, 16(13), 4868; https://doi.org/10.3390/ma16134868 - 07 Jul 2023
Cited by 1 | Viewed by 825
Abstract
This study analysed flexural properties, microhardness, and the degree of conversion (DC) of five bulk-fill composites under clinically relevant conditions (4 mm thick specimens) in comparison to 2 mm specimens according to ISO 4049. Additionally, the effect of rapid polymerisation on 4 mm [...] Read more.
This study analysed flexural properties, microhardness, and the degree of conversion (DC) of five bulk-fill composites under clinically relevant conditions (4 mm thick specimens) in comparison to 2 mm specimens according to ISO 4049. Additionally, the effect of rapid polymerisation on 4 mm specimens was evaluated after accelerated aging. DC was measured using Fourier transform infrared spectrometry at 2 and 4 mm thick layers, while flexural properties and Vickers microhardness were tested using 16 × 2 × 2 mm or 16 × 2 × 4 mm specimens. Three polymerisation protocols were used: (I) “ISO”: 2 mm thickness, 1000 mW/cm2, double-sided; (II) “10 s”: 4 mm thickness, 1000 mW/cm2, one-sided; and (III) “3 s”: 4 mm thickness, 2600 mW/cm2, one-sided. Mechanical properties were tested after 1 day, after 10,000 thermocycles, and after 10,000 thermocycles followed by a 7-day immersion in absolute ethanol. The “ISO” protocol produced a higher DC and microhardness of all materials. Elastic modulus was significantly higher for the “ISO” protocol compared to the 4 mm specimens. The differences in flexural strength for all polymerisation protocols were equalised after thermocycling and immersion in absolute ethanol. All tested materials met the ISO 4049 flexural strength requirement (80 MPa) for all polymerisation methods and all aging conditions. Rapid polymerisation achieved nearly optimal properties (ISO), except for elastic modulus, which was significantly reduced in 4 mm samples. Full article
(This article belongs to the Special Issue Novel Dental Restorative Materials (Volume II))
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16 pages, 2392 KiB  
Article
Effect of Physical Properties on Mechanical Behaviors of Sandstone under Uniaxial and Triaxial Compressions
by Esraa M. Alomari, Kam W. Ng, Lokendra Khatri and Shaun S. Wulff
Materials 2023, 16(13), 4867; https://doi.org/10.3390/ma16134867 - 06 Jul 2023
Viewed by 1306
Abstract
Mechanical properties of sandstone, such as compressive strength and young’s modulus, are commonly used in the design of geotechnical structures and numerical simulation of underground reservoirs using models such as the digital groundwater, equivalent porous medium, and Discrete Fracture Network (DFN) models. A [...] Read more.
Mechanical properties of sandstone, such as compressive strength and young’s modulus, are commonly used in the design of geotechnical structures and numerical simulation of underground reservoirs using models such as the digital groundwater, equivalent porous medium, and Discrete Fracture Network (DFN) models. A better understanding of the mechanical behaviors of sandstone under different loading conditions is imperative when assessing the stability of geotechnical structures. This paper highlights the effect of the physical properties (i.e., porosity, mean grain size) and environmental conditions (i.e., water content and confining stress) on uniaxial compressive strength, triaxial compressive strength, and young’s modulus of sandstone. A series of uniaxial and triaxial compression experiments are conducted on sandstone formations from Wyoming. In addition, experimental data on sandstones from the literature are compiled and integrated into this study. Prediction equations for the compressive strengths and young’s modulus of sandstone are established based on commonly available physical properties and known environmental conditions. The results show that the mean Uniaxial Compressive Strength (UCS) decreases as the porosity, water content, and mean grain size increase. Furthermore, a predictive empirical relationship for the triaxial compressive strength is established under different confinements and porosity. The relationship suggests that the mean peak compressive strength increases at a higher confinement and decreases at a higher porosity. The results and recommendations provide a useful framework for evaluating the strength and deformation of most sandstone. Full article
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12 pages, 7306 KiB  
Article
Synthesis and Characterization of a New Cu(II) Paddle-Wheel-like Complex with 4-Vinylbenzoate as an Inorganic Node for Metal–Organic Framework Material Design
by Egla Yareth Bivián-Castro, Marcos Flores-Alamo, Roberto Escudero, Virginia Gómez-Vidal, José J. N. Segoviano-Garfias, Jesus Castañeda-Contreras and Quetzalcoatl Enrique Saavedra-Arroyo
Materials 2023, 16(13), 4866; https://doi.org/10.3390/ma16134866 - 06 Jul 2023
Cited by 1 | Viewed by 1418
Abstract
A new Cu(II) paddle-wheel-like complex with 4-vinylbenzoate was synthesized using acetonitrile as the solvent. The complex was characterized by X-ray crystal diffraction, FT-IR, diffuse reflectance spectroscopy, thermogravimetric, differential scanning calorimetric, magnetic susceptibility, and electronic paramagnetic resonance analyses. The X-ray crystal diffraction analysis indicated [...] Read more.
A new Cu(II) paddle-wheel-like complex with 4-vinylbenzoate was synthesized using acetonitrile as the solvent. The complex was characterized by X-ray crystal diffraction, FT-IR, diffuse reflectance spectroscopy, thermogravimetric, differential scanning calorimetric, magnetic susceptibility, and electronic paramagnetic resonance analyses. The X-ray crystal diffraction analysis indicated that each copper ion was bound at an equatorial position to four oxygen atoms from the carboxylate groups of the 4-vinylbenzoate ligand in a square-based pyramidal geometry. The distance between the copper ions was 2.640(9) Å. The acetonitrile molecules were coordinated at the axial position to the copper ions. Exposure of the Cu(II) complex to humid air promoted the gradual replacement of the coordinated acetonitrile by water molecules, but the complex structure integrity remained. The EPR spectra exhibited signals attributed to the presence of a mixture of the monomeric (S = ½) and dimeric (S = 1) copper species in a possible 3:1 ratio. The magnetic studies revealed a peak at 50–100 K, which could be associated with the oxygen absorption capacity of the Cu(II)–vba complex. Full article
(This article belongs to the Special Issue Synthesis and Application of Metal-Organic Framework Materials)
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19 pages, 6114 KiB  
Article
3D Model of Heat Flow during Diffusional Phase Transformations
by Łukasz Łach and Dmytro Svyetlichnyy
Materials 2023, 16(13), 4865; https://doi.org/10.3390/ma16134865 - 06 Jul 2023
Cited by 1 | Viewed by 921
Abstract
The structure of metallic materials has a significant impact on their properties. One of the most popular methods to form the properties of metal alloys is heat treatment, which uses thermally activated transformations that take place in metals to achieve the required mechanical [...] Read more.
The structure of metallic materials has a significant impact on their properties. One of the most popular methods to form the properties of metal alloys is heat treatment, which uses thermally activated transformations that take place in metals to achieve the required mechanical or physicochemical properties. The phase transformation in steel results from the fact that one state becomes less durable than the other due to a change in conditions, for example, temperature. Phase transformations are an extensive field of research that is developing very dynamically both in the sphere of experimental and model research. The objective of this paper is the development of a 3D heat flow model to model heat transfer during diffusional phase transformations in carbon steels. This model considers the two main factors that influence the transformation: the temperature and the enthalpy of transformation. The proposed model is based on the lattice Boltzmann method (LBM) and uses CUDA parallel computations. The developed heat flow model is directly related to the microstructure evolution model, which is based on frontal cellular automata (FCA). This paper briefly presents information on the FCA, LBM, CUDA, and diffusional phase transformation in carbon steels. The structures of the 3D model of heat flow and their connection with the microstructure evolution model as well as the algorithm for simulation of heat transfer with consideration of the enthalpy of transformation are shown. Examples of simulation results of the growth of the new phase that are determined by the overheating/overcooling and different model parameters in the selected planes of the 3D calculation domain are also presented. Full article
(This article belongs to the Special Issue Microstructure and Mechanical Properties of Alloys and Steels)
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23 pages, 7582 KiB  
Article
Tensile Behaviors and Mechanical Property Analyses of T-Welded Joint for Thin-Walled Parts in Consideration of Different TIG Welding Currents Using Multiple Damage Models and Fracture Criterions: Numerical Simulation and Experiment Validation
by Minghui Pan, Yuchao Li, Siyuan Sun, Wenhe Liao, Yan Xing and Wencheng Tang
Materials 2023, 16(13), 4864; https://doi.org/10.3390/ma16134864 - 06 Jul 2023
Viewed by 1160
Abstract
In order to deeply investigate the tensile properties and fracture behaviors that are obtained by tensile tests of welded joints, constitutive and damage models are imperative for analyzing the tensile behaviors. In this work, the tensile tests are conducted on the T-welded joint [...] Read more.
In order to deeply investigate the tensile properties and fracture behaviors that are obtained by tensile tests of welded joints, constitutive and damage models are imperative for analyzing the tensile behaviors. In this work, the tensile tests are conducted on the T-welded joint specimens of aluminum alloy 6061-T6, which were cut from the T-welded joints of thin-walled parts under different welding currents of Tungsten Inert Gas Welding (TIGW). A modified Johnson-Cook (J-C) model based on the original J-C equation, Swift model, Voce model, and Hockett-Sherby (H-S) model, their linear combination model, and fracture failure model are constructed and applied to simulate tensile behaviors, combined with tensile test data. What is more, the finite element (FE) simulation of tension tests is executed with the VUMAT and VUSDFLD subroutines. Compared to those results simulated with different fracture criteria and tensile experiments, the tensile strength and yield strength of T-welded joint thin-walled parts under different welding currents were achieved, and their best mean errors were only about 1%. Furthermore, the accuracy of different fracture criteria is also evaluated by the correlation coefficient and mean squared error. The results show that the combination model can accurately predict the tensile properties and fracture behaviors of T-welded joints better than the single model, especially the results simulated with the Swift-H-S model and H-S-Voce model, which are in good agreement with tensile test results, which will provide an analysis foundation for enhancing the welding assembly quality and preventing fracture failure for complex thin-walled antenna structures. Full article
(This article belongs to the Special Issue Mechanics, Fatigue and Fracture of Metallic Materials)
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3 pages, 196 KiB  
Editorial
Surface Engineering & Coating Technologies for Corrosion and Tribocorrosion Resistance
by Yong Sun
Materials 2023, 16(13), 4863; https://doi.org/10.3390/ma16134863 - 06 Jul 2023
Cited by 2 | Viewed by 795
Abstract
Corrosion of materials not only accounts for about 3 to 4% of economic losses in GDP in an industrial nation, but it also contributes significantly to greenhouse emissions and climate change because material production is one of the largest greenhouse emitters [...] Full article
(This article belongs to the Special Issue Surface Engineering & Coating Technologies for Corrosion and Tribocorrosion Resistance)
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