Strength Of Composites Research Articles

Regulating the mechanical properties of (μm B4C+nm SiC)/7075Al composites via nano-SiC content

In this study, micron B4Cp (m-B4Cp) and nanometer SiCp (n-SiCp) reinforced 7075Al composites were prepared by high-energy ball milling, hot press sintering, and hot extrusion. The microstructures and mechanical properties of composites were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), tensile testing, and synchrotron radiation computed microtomography (SR-μCT). The results showed that n-SiCp and m-B4Cp were uniformly distributed in the aluminum matrix without interfacial reaction. The optimal grain refinement was achieved by adding 1.5 wt% n-SiCp, improving the strength and ductility of composites. The room temperature yield strength (YS) and ultimate tensile strength (UTS) of M5N1.5 composites were increased from 350 MPa and 401 MPa of 7075Al to 460 MPa and 502 MPa, respectively. The results revealed that the YS and UTS of composites were decreased, but elongation was increased with increasing temperature. When the temperature increased to 200 °C, the elongation of 7075Al and M5N1.5 was increased from 5.9 % and 4.7 % to 8.7 % and 10.9 %, respectively. Quantitative analysis revealed that dislocation strengthening and grain refinement strengthening caused by the addition of n-SiCp are the dominating strengthening mechanisms at both room and high temperature, while the contribution of m-B4Cp to the strengthening of the composites is very small.

Enhancing the mechanical and electrochemical corrosion properties of Cu composites via manipulation of intragranular graphene quantum dots cluster

Intragranular distribution of reinforcements is highly valued for simultaneously improving strength and corrosion resistance in metal composites. Here, we manipulated zero-dimensional graphene quantum dots (GQDs) clusters into Cu grain interiors via a “nanodispersion-in-grains” strategy. The uniformly dispersed GQDs clusters activate multiple hardening mechanisms resulted in superior mechanical strengthening efficiency (Seff = 228). Furthermore, GQDs clusters contribute to induce the twin domains in composites via forming high stress field, which would elevate the grain boundary stability and in turn restrained the corrosion process. Compared with pure Cu, 0.2 GQDs/Cu composite has a lower corrosion current density (1.50 × 10−5 A cm−2), reducing the corrosion rate by 31.2%. Our work has provided a feasible route to broaden the Cu composites application as reliable structural components.

Applicability and chemical mechanism of lightweight cement composite containing fly ash and sand for sustainable embankment

Lightweight embankment is an effective method for soft foundation treatment, while decreasing its cement usage can protect environment, save resource and reduce cost. This study aims to develop a lightweight cement composite (LC) containing fly ash and sand to provide guidance for filling the sustainable embankment. The chemical mechanism, micro-morphology, mechanical strength and workability of lightweight cement composites were evaluated through macro-micro tests, as well as life cycle assessment was performed to analyze the sustainability, and determine the optimal mixing ratio. The results showed that the moderate amount of fly ash was beneficial to enhance the mechanical strength of LC, while adding sand further improved its ductility, toughness, workability and sustainability. When the replacement rate of fly ash and sand were 10 % and 20 %, the energy absorption and fluidity of LC increased by 57 % and 7 %, and its ductility index, carbon emission and construction cost decreased by 34 %, 46 % and 35 %, respectively. Fly ash reacted with calcium hydroxide produced by cement hydration to generate more calcium silicate gels, which reduced the large pore of LC and improved its internal structure, while sand played a certain skeleton role.

Schematic construction of carbon fiber tow microstructure models and their effect on tensile strength of carbon fiber tow/epoxy composites: Quantification of carbon fiber distribution, misalignment, and interlacing

Carbon fiber reinforced polymers (CFRPs) are increasingly being used in cutting-edge technologies, thus rendering accurate material characterization essential. However, the unexpected microstructures of carbon fiber (CF) tows, such as random fiber distribution, misalignment, and interlacing, degrade the mechanical properties of CFRPs and render them unpredictable. Hence, the microstructures of CF tows and their effect on the performance of CFRPs must be investigated.Herein, we propose a framework for quantifying the microstructural parameters of three types of T700 grade CF tows and investigate their effects on the tensile strengths of CF tows and CF tow-reinforced composites. CF cross sections are analyzed via microscopy to measure the fiber distribution and misalignment with respect to the location. A two-roll mill experiment is designed to evaluate fiber interlacing by compressing the CF tow in the thickness direction. The tensile strengths of CFs, CF tows, and CF tow-reinforced composites are measured, whereas their interfacial shear strengths are obtained via a micro-droplet test.Two CF tow microstructure models are proposed: the uniform distribution model with a low degree of fiber misalignment resulted in a higher tensile strength ratio of CF tow compared to the core-shell model, as well as a higher tensile strength of CF tow/epoxy composites. Results indicate that the microstructure of the CF tow significantly affects the properties of the composite materials. Therefore, utilizing the framework proposed herein as a tow design parameter is expected to fulfill the varying requirements of important properties in composite material design based on the application field.

Investigating the spall phenomena in glass filler embedded epoxy composites using laser-induced stress wave

Recently, Singh and Kitey (Experimental Mechanics, 60(7), 2020) used laser-induced stress pulse in conjugation with Michelson's interferometer to measure the spall strength of thin polymer layers. In this investigation, the method is expanded to measure the spall strength of spherical and slender glass filler-reinforced epoxy composites. A filler-reinforced epoxy layer of ∼150 μm was deposited onto a glass substrate, and a short-duration and high-magnitude stress pulse developed at the back surface of the substrate. A complex interaction between the mode-converted main compressive wave and slow-moving secondary tensile wave generated a greater magnification tensile area near the layer's free surface, causing a spall. The composite layers experienced a strain rate of ∼107/s, with the secondary wave not distinct from the interferometric data due to filler-induced multiple mode conversions. An equation correlating strain rate, impedance, and fracture toughness with spall strength was used to ascertain the composite layers' spall strength. The findings showed that stiff reinforcements improve epoxy spall strength, with milled fiber composites exhibiting greater spall strength than spherical particle cases, as corroborated by optical micrographs showing fiber-bridging across the spalled zone. The spall strength of epoxy composites with 10 % milled fibers was nearly 2.5 times greater than pure epoxy.

Effect of high plant protein/peptide nutrition supplementation on knee osteoarthritis in older adults with sarcopenia: A randomized, double-blind, placebo-controlled trial

Background & AimsSkeletal muscle is an important contributor to joint health. Previous studies have shown that age-related muscle mass and strength loss are closely associated with the development of knee osteoarthritis. The objective of this study is to investigate whether a high plant protein/peptide nutrition supplementation can alleviate knee osteoarthritis by improving muscle mass and strength. MethodsThis randomized, double-blind, placebo-controlled trial that included participants aged 50–70 years diagnosed with knee osteoarthritis and sarcopenia was conducted in China from February 2022 to September 2022 (ChiCTR2200056415). Participants were randomized to receive a 12-week high plant protein/peptide nutrition supplementation or a placebo twice daily, with one serving each after breakfast and lunch, respectively. The primary outcome analyzed using intention-to-treat analysis was difference in Short Physical Performance Battery (SPPB) from baseline to week 12 between the two groups. The secondary outcomes included changes in muscle mass, strength, symptom and imaging of knee osteoarthritis, body composition, biochemical parameters, and health quality scores. ResultsAfter 12 weeks, a total of 124 participants (38.7% male) completed the trial and were included in the final analysis. Over the 12-week follow-up, the experimental group showed a significant improvement in the SPPB total score (1.03, 95% CI, 0.69 to 1.38, P < 0.0001) compared with the placebo group. Grip strength (2.83 kg, 95% CI, 2.13–3.53, P < 0.0001) and skeletal muscle mass index (0.66 kg/m2, 95% CI, 0.45–0.86, P < 0.0001) were also significantly increased in the experimental group compared with the placebo group. The mean change in Western Ontario and McMaster Universities Osteoarthritis Index total score was −3.95 points (95% CI, −5.02 to −2.89, P < 0.0001) in the experimental group and 0.23 points (95% CI, −0.17 to 0.63, P = 0.253) in the placebo group. Additionally, within the experimental group, nine participants experienced an improvement in osteophyte magnetic resonance imaging results, while no improvement was observed in the placebo group. The experimental group also exhibited significant improvements in health quality compared with the placebo group as assessed by Short Form 36, the World Health Organization Quality of Life Brief Scale, and the Chalder Fatigue Scale. No serious adverse event was reported during the trial. ConclusionOral supplementation with high levels of plant protein/peptides can alleviate symptoms of osteoarthritis in elderly individuals with minor and mild knee osteoarthritis and sarcopenia. The improvement may be attributed to the enhancement of muscle mass, strength, and physical performance.

Poly(vinyl chloride) composites reinforced with wood flour and calcinated halloysite

ABSTRACT Hybrid poly(vinyl chloride) composites were prepared by adding calcinated halloysite and wood flour to the PVC matrix by mixing in a molten state. The mechanical (DMTA analysis, tensile strength, strain at break, Young’s modulus, hardness and impact strength) and thermal (thermal stability, Vicat softening temperature and heat deflection temperature) properties of the composites were tested. The plastographometric analysis suggests that simultaneous addition of two fillers of different origins to the PVC matrix results in a longer gelation time and higher torque values than those observed for neat PVC. Moreover, the presence of calcinated halloysite in PVC/wood flour composites leads to the rise of weight loss temperature compared to PVC composites with only wood flour. When added to PVC/halloysite composites, wood flour improves their homogeneity by breaking halloysite agglomerates, which ensures approx. 116% better thermal stability (confirmed in the Congo red test) compared to unfilled PVC. The synergistic effect of the fillers used on the mechanical properties is demonstrated by the 14.4% higher stiffness and 22.5% higher tensile strength of the PVC composites containing wood flour and 5 wt% halloysite compared to the material loaded with wood flour only.

Compressive strength, chloride-ion-penetration resistance, and crack-recovery properties of self-healing cement composites containing cementitious material capsules and blast-furnace-slag aggregates

Blast-furnace-slag aggregate (BFSA), a by-product of the steel industry, is an eco-friendly natural, aggregate substitute used in mortar and concrete. However, research on self-healing cement composites using BFSA is rare. In this study, the compressive strength, chloride-ion-penetration resistance, and crack-recovery properties of self-healing cement mortar samples prepared using cementitious material capsules (CMC) and BFSA of different ratios were examined and compared to a control sample. The test samples were: Control; C05B00 (5 % CMC and 0 % BFSA); C05B25 (5 % CMC and 25 % BFSA); C05B50 (5 % CMC and 50 % BFSA); C10B00 (10 % CMC and 0 % BFSA); C10B25 (10 % CMC and 25 % BFSA); and C10B50 (10 % CMC and 50 % BFSA). The compressive-strength recovery rate of the control stopped increasing after 28 days and was approximately 110 % on day 56 – that of C10B50 was approximately 121 %, (∼10 % greater than that of the control) and continued to increase even after 56 d. The chloride-ion-penetration resistance of C10B50 was excellent; the 28-day total charge was approximately 5858 C (∼ 40.2 % lower than that of the control). The crack-recovery rates, on day 28, of C05B50 and C10B25 were 71 % and 70 %, respectively (∼ 29–30 % higher than that of the control).

Structure Investigation of highly porous bioceramics based on biogenic hydroxyapatite with graphene oxide coating

Highly porous bioceramics (porosity equal to 93–94 %) based on biogenic hydroxyapatite and sodiumborosilicate glass (40wt% of glass) was prepared by foam replication method at 700 °C and coated by graphene oxide using CVD method. Obtained bioceramics samples were studied by SEM, XRD and Raman spectroscopy. Phase composition, morphology, skeleton density, porosity and compression strength were evaluated. It was shown that biogenic hydroxyapatite in highly-porous bioceramics composition is stable and keeps hydroxyapatite phase without secondary phase formation after sintering with sodiumborosilicate glass as well as after application of CVD method for graphene oxide coating. Formation of graphene oxide for coated bioceramics was confirmed by XRD, SEM and Raman spectroscopy. Significant effect of graphene oxide coating on the porosity and skeleton density was not detected due to thin layer and low content of graphene oxide, but it allows 30 % increasing the compression strength of highly porous bioceramics.

Plasma C-terminal agrin fragment concentrations across adulthood: Reference values and associations with skeletal muscle health.

Increasing interest surrounds the utility of blood-based biomarkers for diagnosing sarcopenia. C-terminal agrin fragment (CAF), a marker of neuromuscular junction stability, is amongst the most promising candidates; however, a dearth of reference data impedes the incorporation of its use in public health settings. This study aimed to establish reference values for plasma CAF concentrations across adulthood in a large, well-characterized cohort of healthy adults; and comprehensively examine the association between plasma CAF levels and skeletal muscle health. One thousand people aged between 18 and 87years took part in this study (mean age=50.4years; 51% females). Body composition and muscle strength were examined using DXA and hand dynamometry. Plasma CAF concentrations were measured, in duplicate, using commercially available ELISA kits. Sarcopenia and individual sarcopenia signatures [low skeletal muscle index (SMI) only/low grip strength only] were classified using the EWGSOP2 algorithm. Detailed reference CAF values, according to sex and age, are presented. A significant but modest age-related increase in plasma CAF concentration was observed (P=0.018). Across adulthood, CAF concentrations were negatively associated with grip strength and SMI (both P<0.001). In people ≥50years old, CAF concentrations were 22.6% higher in those with sarcopenia (P<0.001), 11.3% higher in those with low SMI (P=0.006) and 9.6% higher in those with low grip strength (P=0.0034), compared with controls. People in the highest CAF concentration quartile, had 3.25 greater odds for sarcopenia (95% CI=1.41-7.49, P=0.005), 2.76 greater odds for low SMI (95% CI=1.24-5.22, P=0.012), and 2.56 greater odds for low grip strength (95% CI=1.07-5.57, P=0.037), compared with those in the lowest quartile. People with a CAF Z-score ≥2 had 9.52 greater odds for sarcopenia (95% CI=3.01-30.05, P<0.001) compared with a Z-score <1. Plasma CAF concentration had an acceptable level of diagnostic accuracy for sarcopenia (AUC=0.772, 95% CI=0.733-0.807, P<0.001). The reference values presented herein may guide the clinical interpretation of circulating CAF and help identify people at risk of poor skeletal muscle outcomes for inclusion in therapeutic interventions. Our findings add clarity to existing data, demonstrating a robust relationship between circulating CAF and skeletal muscle integrity in the largest adult cohort to date, and support the use of CAF as an accessible, cost-effective screening tool for sarcopenia. However, further research into the prognostic utility of plasma CAF, and the establishment of normative data from other populations, are urgently needed if routine CAF screening is to be embedded into public healthcare settings.

Mechanical and thermal properties of glass fiber reinforced polymer-clay nanocomposites

Abstract The effect of Montmorillonite (MMT) nanoclay on static mechanical and thermal characteristcs of glass fiber-reinforced polymer (GFRP) composites is studied. The static tensile properties of epoxy/MMT nanoclay, which are important properties of GFRP composites, are investigated. The predicted stress-strain curves of epoxy with 0 and 1 wt.% of nanoclay follow experiments. The predicted elastic modulus and tensile strength of epoxy with 3 wt.% of nanoclay are 74 and 230% higher than neat epoxy. For GFRP composites with 0, 1, 3, and 5 wt.% of MMT nanoclays, the measured tensile strengths are 587, 600, 628, and 724 MPa, and flexural strengths are 626, 726, 906, and 542 MPa. For composites with former nanoclays, interlaminar shear strengths are 23, 25, 31, and 28 MPa, and Izod impact strengths are 83, 94, 207, and 145 kJ/m2. Thus, mechanical strengths of composites with 0–5 wt.% of nanoclays improve considerably than pristine sample. The predicted static tensile stress-strain curves of GFRP composites with above nanoclays follow experimental behavior. For GFRP composites with 0 and 1 wt.% of MMT nanoclays, glass transition temperatures are 91 and 101°C, and storage moduli at ambient temperature are 35 and 41 GPa. The thermal conductivities of GFRP composites with 0, 1, and 3 wt.% of MMT nanoclays at ambient temperature are 0.32, 0.36, and 0.42 W/(m·K). Thus, thermal properties of composites are affected significantly on addition of nanoclays.

Influence of evolution in reinforcement scale characteristic parameters on the microstructure and properties of Ti6Al4V-TiBw composites fabricated by electron beam powder bed fusion

The size, aspect ratio, and distribution of reinforcement, referred to as the scale characteristic parameters (SCP), are critical factors that influence the mechanical properties of discontinuous reinforced titanium matrix composites (DRTMCs). To investigate the impact of SCP evolution on the microstructure and mechanical properties of TiBw, this study employed spherical Ti6Al4V-TiBw composite powder prepared by electrode induction melting gas atomization (EIGA) as feedstock for fabricating Ti6Al4V-TiBw composites through electron beam powder bed fusion (EB-PBF) process. By implementing a two-step rapid cooling approach in EIGA and EB-PBF processes to “freeze” the TiBw at nanoscale within Ti6Al4V-TiBw composites, a significantly wider regulation window for microstructure and mechanical properties was achieved. Subsequently, heat treatment was conducted at temperatures ranging from 850 to 1200 °C to systematically elucidate the mutual influence regulation among SCPs, microstructure, and mechanical properties of TiBw. Based on our findings, it can be concluded that when subjected to heat treatment temperatures higher than 950 °C, an orientation relationship between TiBw and α-Ti is observed: {0001} α-Ti//{001} TiBw, {11 2‾ 0} α-Ti//{010} TiBw, {10 1‾ 0} α-Ti//{100} TiBw. Additionally, the cross-section of columnar-shaped TiBw exhibits semi-coherent interfaces with coherent interfaces bonded to Ti along its (100) crystal plane while displaying incoherent interfaces with Ti matrix along its (101) and (10 1‾) crystal planes. The strength of Ti6Al4V-TiBw composites exhibited a trend of initial increase followed by decrease with the evolution of TiBw scale characteristic parameters, while the elongation demonstrated an overall decreasing pattern. This research aims to establish a foundation for microstructure and properties control of DRTMCs and provide experimental references and theoretical basis for high-performance DRTMCs research.

Preparation and Characterization of Hydroxyapatite Based Composite Material via Cold Sintering Process

This study focuses on the synthesis of hydroxyapatite (HA) from bovine bones through calcination and subsequent combination with Polyvinyl Alcohol (PVA) using the Cold Sintering Process (CSP). The CSP, operating at lower temperatures than conventional methods, aims to preserve the bioactivity and biocompatibility of HA, crucial for biomedical applications. The research investigates the influence of HA composition, sintering temperature, and PVA content on the porosity and compressive strength of the HA-PVA composite. The Hydroxyapatite powder, obtained from calcinated bovine bones, exhibits irregular shapes and sizes with a maximum grain size of 10µm, confirmed by SEM analysis. XRD analysis validates the successful production of Hydroxyapatite, showcasing characteristic peaks. The HA/PVA composite's XRD pattern indicates the dominance of HA, with PVA present as well. The study produces 27 specimens through the CSP, varying HA composition and sintering temperature. Porosity increases with higher HA content and sintering temperature, attributed to the role of PVA in binding HA particles. Compressive strength rises with increased HA content, emphasizing HA's role in enhancing mechanical strength. The presence of porosity is mitigated by a strong bond between HA and PVA, contributing to structural integrity. This research provides insights into tailoring HA-PVA materials for biomedical applications, considering controlled porosity and mechanical strength. The CSP, with its unique advantages, emerges as a promising method for developing customized materials to meet diverse biomedical needs.

Modification on Fiber from Alkali Treatment and AESO Coating to Enhance UV-Light and Water Absorption Resistance in Kapok Fiber Reinforced Polyester Composites

ABSTRACT Environmental contamination poses a significant threat to the integrity of materials, including metals and composites. Addressing the degradation of natural fiber-reinforced polymer composites necessitates effective management strategies, particularly in mitigating UV and water-induced deterioration. This study explores the efficacy of Acrylated Epoxidized Soybean Oil (AESO) coating treatment following alkali treatment as a potential solution. Alkali treatment of Kapok fiber (KF) combined with polymer coating yielded composites exhibiting superior mechanical properties, particularly in tensile and flexural strength, following a 30-day aging period. Remarkably, the application of alkali and coating treatments led to a substantial enhancement in the mechanical strength of polyester composites, with the highest tensile strength recorded at 96.04 MPa. This represented a notable increase of 31.97% compared to untreated KF specimens. The observed enhancement in composite performance underscores the critical role of interfacial adhesion between fibers and the matrix, particularly under conditions of UV exposure and water immersion. Importantly, the study demonstrates that alkali treatment and polymer coating effectively mitigate degradation in Natural Fiber-Reinforced Polymer Composites, thereby offering promising avenues for enhancing their durability and longevity.

Development and characterization of hybrid polymer composite materials with reinforcement of glass/carbon fibers for enhanced mechanical properties: an experimental and numerical approach

Composite materials, particularly fiber-reinforced plastics (FRP), are used in aerospace and automotive industries due to their desirable properties and surpassing traditional metals in various applications. Researchers are countering the drawbacks of using a single fiber type in FRP by creating hybrid composites that combine different fibers in a single matrix. These hybrids harness the cost-effectiveness and corrosion resistance of glass fibers alongside the strength and stiffness of carbon fibers, resulting in a balanced combination of properties for various applications. Tensile tests were performed according to the ASTM D3039 standard, with a 2 mm/min strain rate. The results showed that increasing the carbon fiber percentage (6.56%, 13.79%, and 21.07%) led to significant improvements in the tensile strength of the hybrid composites (34.18%, 55.44%, and 85.40% higher than glass fiber composites). However, changing the stacking sequence did not significantly affect tensile strength, indicating its insignificance in this regard. Numerical simulations were conducted to validate the experimental results, and the errors between experimental and numerical data were below 10% for various stacking sequences. These discrepancies were attributed to factors such as fiber waviness, which resulted in heterogeneous property distribution within the composites, and the manufacturing process used for creating the hybrid composites. Scanning electron microscope analysis was also performed to study the failure modes on the fracture surface of the tensile-tested specimens.

Dynamic Effect of Ply Angle and Fiber Orientation on Composite Plates

Composite materials have revolutionized industries such as aerospace and automotive with their impressive strength-to-weight ratios and customizable properties. Ply angle and fiber orientation are critical factors that significantly impact the dynamic behavior of composite structures, influencing stiffness, strength, and vibrational characteristics. This research delves into the dynamic characteristics of composite plates, explicitly examining how ply angle and fiber orientation affect vibrational behavior. Through finite element analysis (FEA), composite plates with varying ply angles and fiber orientations were modeled to understand their influence on natural frequencies, mode shapes, and dynamic responses under various loading conditions. The study reveals that cross-ply [0/0/0/0] exhibits the highest stiffness and superior stress handling, while the cross-ply balanced laminate [90/0/0/90] demonstrates better vibrational characteristics. The findings highlight the intricate relationships between design parameters and structural vibrational behavior, offering opportunities for optimizing composite structures. Additionally, harmonic analysis showed that a cut-out increases the natural frequency. The results underscore the importance of optimizing composite plate configurations to enhance vibrational characteristics and align natural frequencies with operational requirements, thereby mitigating resonance-related issues.

Preparation and characterization of ox bone powder and bamboo fibers reinforced hybrid epoxy composites

Composite materials are one of the fastest growing when compared with metal, ceramic, and polymer due to their high specific strength, stiffness, and versatile application in various fields. This study aimed to develop an ox bone powder and bamboo fiber-reinforced hybrid epoxy composite for stock and bumper applications and investigate the effect of the reinforcements on the composite’s mechanical properties. The reinforcements used in this work were random orientations of animal bone (ox) powder of 75 microns and bamboo fiber. The matrix used for this work was epoxy resin. Composite materials were prepared using the hand layup method with a 40% weight fraction of reinforcement (bone powder and bamboo fiber) and a 60% weight fraction of epoxy resin matrix. Five different combinations of bone powder and bamboo fiber with a fixed amount of epoxy resin were used for this work. The combinations of bamboo fiber and bone powder were: 40% bamboo fiber with 0% bone powder; 30% bamboo fiber with 10% bone powder; 20% bamboo fiber with 20% bone powder; and 0% bamboo fiber with 40% bone powder. The mechanical properties studied were compressive strength, impact strength, and flexural strength. In addition, water absorption was studied for all combinations. The maximum results of the flexural and impact strengths were 278.91 MPa and 7.5 J/m, respectively, at a 0:40 (bone powder: bamboo fiber) composite. The maximum compressive strength and the lowest absorption obtained were 283.3 MPa and 1.05%, respectively, at the 40:0 (bone powder: bamboo fiber) composite. For the hybrid composite case, optimal flexural and impact strengths were 236.72 MPa and 6.66 J/m, respectively, and water absorption was 1.52% at 10:30 (bone powder: bamboo fiber). Since reasonable flexural strength, impact strength, and water absorption were obtained with the hybrid composite of 10:30 (bone powder: bamboo fiber), this combination of the hybrid composite is recommended for stock and bumper applications.

Multifunctional Ta4C3Tx MXene/HTPP - PBS composites with multi cross-linking systems to cope with complex nuclear environments

The development of multifunctional radiation protection materials is crucial to ensure the safety of personnel and equipment in complex nuclear environments. Herein, a flexible radiation protection material integrating self-healing, thermal management, and behaviour response was prepared from Ta4C3Tx MXene, Hydrogen-terminated phenyl polysiloxane, and Polyborosiloxane through esterification, “thiol-ene click” hydrosilylation reaction using L(+)-Cysteine as a bridge. The results showed that when Ta4C3Tx MXene reached 20 wt%, the tensile strength of composite was 0.6321 MPa with the self-healing rate at 90.22 %. And the gauge factor of the material reached 25.83 at 100 % strain. This compensated for the gap between low strain and high sensitivity. Additionally, the multilayer structure of Ta4C3Tx MXene and the absorption properties of Tantalum enable the material to attenuate γ-rays through absorption and scattering mechanisms. The attenuation capability of Ta2O5 and Ta4C3Tx MXene fillers for 59.6 KeV γ-rays was compared at the same Tantalum content. When the Tantalum content reaches 23.81 wt%, the Ta4C3Tx MXene composite contains 20 wt% filler and has an attenuation coefficient of 0.757. Similarly, the Ta2O5 composite contains 22.5 wt% filler and has an attenuation coefficient of 0.734. These results are significant for improving temperature and behaviour monitoring of workers in low-temperature nuclear environments.

Electric-field induced phase separation and dielectric breakdown in leaky dielectric mixtures: Thermodynamics and kinetics.

Dielectric materials form the foundation of many electronic devices. When connected to a circuit, these materials undergo changes in microscopic morphology, such as the demixing of dielectric mixtures through phase separation and dielectric breakdown, resulting in the formation of micro-filaments. Consequently, the macroscopic properties and lifespan of the devices are significantly altered. To comprehend the physical mechanisms behind it, we conducted a systematic investigation of the thermodynamics of multicomponent leaky dielectric materials. Beginning with the total energy functional, we derived expressions for the binodal composition, spinodal composition, and critical points. Furthermore, we constructed and validated theoretical phase diagrams for the binary leaky dielectric mixture, incorporating three crucial freedoms: composition, temperature, and electric field strength. In addition, we analyzed the equilibrium interfacial tension impacted by the electric field and studied the dynamic aspects of dielectric materials, examining two morphological transformations: electrostriction and dielectric breakdowns. Our analysis unveiled a connection between these dynamic phenomena and the electric field-induced interfacial instability. The present work is expected to be supportive of future research on multicomponent dielectric materials by offering a comprehensive understanding of their thermodynamic and kinetic behaviors.

Investigation on Critical Microstructure Size for Numerical Analysis of Metal-Matrix Composites with Network Reinforcement Architecture

Finite element method (FEM) is a powerful tool to predict the properties and reveal the mechanisms of metal-matrix composites (MMCs) with very complex architectures and novel microstructures. Recent studies have demonstrated the effectiveness of network reinforcement architectures on simultaneous strengthening and toughening. Here, as a key factor in modeling network architecture, the critical microstructure size was studied via FEM. We found that a critical microstructure size of 23 [Formula: see text]m (cell count [Formula: see text]20) existed in the FEM model, beyond which the crack deflection may be feasibly induced from particle-rich to matrix regions, leading to crack propagation in the ductile matrix cells and thus high strength and elongation. While, with cell size 20–23 [Formula: see text]m in SiC/6061Al model, the composite strength and elongation remained intact, implying that the maximal microstructure size is 23 [Formula: see text]m for effective network architecture simulations.