Search

Let f (x) be a function on x. The Wiener-type indices, denoted by W f (G) , is defined as W f = W f (G) = ∑ { u , v } ⊆ V (G) f (d G (u , v)). In this note, we use Wiener-type indices to give some sufficient conditions for lower bounds on vulnerability parameters of graphs, including integrity, tenacity, binding number and toughness. Our results generalized existing results of Yatauro (2023). [ABSTRACT FROM AUTHOR]

Twenty types of polyethylene (PE) including high density polyethylene (HDPE) and linear low‐density polyethylene (LLDPE) with various viscosity were used to study the in‐situ formation of PE‐ ethylene propylene rubber (EPR) core‐shell rubber particles (CSRP) in polypropylene (PP) matrix by melt blending. The results show that PE and EPR cannot form CSRP if PE melt flow index (MFI) is lower than about 0.3 g/10 min. As a result, the impact fracture of PP/PE/EPR composite is brittle. If PE MFI is higher than 0.3 g/10 min, PE and EPR can form CSRP, leading to the ductile impact fracture of PP/PE/EPR composite. Interestingly, upper limit content of PE for the formation of CSRP depends on the type and viscosity of PE. For HDPE, upper limit content of PE tends to increase with the increase of its MFI, whereas it drops considerably for LLDPE. Understanding these relationships provides insights into optimizing the selection of core types and viscosity for enhancing the mechanical properties of polymer composites with core‐shell structure. This may potentially guide the development of cost‐effective and high‐performance polymer composites. [ABSTRACT FROM AUTHOR]

The mechanical properties and microstructure of double-hard-phase TiB 2 –25-wt.%-TiC–20-wt.%-CoNi cermets prepared at different temperatures were investigated by performing scanning electron microscopy, X-ray diffraction, and transmission electron microscopy. The results showed that the transverse rupture strength, indentation fracture toughness, hardness, and relative density of the cermets reached the maximum values of 1654 MPa, 11.06 MPa m1/2, 90.1 HRA, and 99.42 %, respectively, when the sintering temperature was 1462 °C. Solid- and liquid-phase sintering occurred at temperatures below and above 1354.5 °C, respectively. The cermets were composed of TiB 2 , TiC, TiB, and CoNi phases when sintered at 1440 °C and below, but the TiB phase disappeared when sintered at 1462 °C and above. Both TiB 2 core–(Ti, Co, Ni)B rim and TiC core–(Ti, Co, Ni)C rim structures appeared in cermets sintered at 1440 °C and above. In addition, a few TiC core–(Ti, W)C inner–(Ti, W, Co, Ni)C outer double rim structures were formed. A coherent interface was found between the (Ti, Co, Ni)B rim and TiB 2 core. A thin CoNi amorphous metallic layer existed at the interface between the (Ti, Co, Ni)C rim and TiC core. In addition, amorphous CoNi was observed in the interfacial region between the CoNi binder and (Ti, Co, Ni)C rim phase and inside the CoNi binder phase. These multi-interface and core–rim structures resulted in excellent strength and toughness of the cermets. [ABSTRACT FROM AUTHOR]

For a set ℋ of connected graphs, a spanning subgraph H of a graph G is an ℋ -factor if every component of H is isomorphic to some member of ℋ. In this paper, we give a criterion for the existence of tight toughness, isolated toughness and binding number bounds in a graph of a strong -star factor, { 1 , 3 , ... , 2 n − 1 } -factor and f -star factor. Moreover, we show that the bounds of the sufficient conditions are sharp. [ABSTRACT FROM AUTHOR]

The { K 1 , 1 , K 1 , 2 , ... , K 1 , k , (2 k + 1) } -factor and { K 1 , 2 , K 1 , 3 , K 5 } -factor of a graph are a spanning subgraph whose each component is an element of { K 1 , 1 , K 1 , 2 , ... , K 1 , k , (2 k + 1) } and { K 1 , 2 , K 1 , 3 , K 5 } , respectively, where (2 k + 1) is a special family of trees. In this paper, we obtain a sufficient condition in terms of tight toughness, isolated toughness and binding number bounds to guarantee the existence of a { K 1 , 1 , K 1 , 2 , ... , K 1 , k , (2 k + 1) } -factor and { K 1 , 2 , K 1 , 3 , K 5 } -factor for any graph. [ABSTRACT FROM AUTHOR]

2219Al alloys microalloyed with varying trace contents (0–0.1 wt.%) of Cd were cast, and subjected to standard sequential thermo-mechanical processes of rolling and age-hardening treatments. Uniaxial tensile and Charpy impact tests were performed, and fractured surfaces were studied under scanning electron microscope (SEM). Variations in tensile ductility and toughness with trace additions of Cd were reported under given processing conditions. Independent influences of Cd compositions, peak-ageing treatment and rolling were investigated to identify predominant fracture modes (ductile/fibrous, brittle/cleavage or mixed) of 2219Al alloys for the first time. Salient features and fracture mechanisms as exhibited from the fractographs were further correlated with microstructural evolution, mechanical ductility and toughness. Cast 2219Al alloy exhibited typically ductile fractographs, compared to moderate level of ductility after microalloying. Lower fracture strain and toughness of peak-aged alloys were accompanied with mixed mode of fracture surfaces. Rolling resulted in fractographs of mixed mode, however with higher ductility compared to peak-aged alloys. Impact testing resulted in failure at higher strain rate, exhibiting typically brittle fractographs, correlated with the impact toughness values. Present fractographic analysis provided a structure-property correlation, to validate the susceptibility of these alloys, to different modes of failure, subjected under various loading and thermo-mechanical treatments. [ABSTRACT FROM AUTHOR]

Polysorbates are non-ionic amphiphilic organic compounds, widely used as surfactants. They have a molecular weight in the 1200–1400 g mol−1 range, so they are on the borderline between monomeric and polymeric plasticizers. Therefore, they can potentially provide the benefits of both plasticizer types. In this work, polyethylene glycol sorbitan monolaurate (Tween® 20), and polyethylene glycol monooleate (Tween® 80) are proposed as environmentally friendly plasticizers for PLA with enhanced ductile properties. The addition of 20 wt% of polysorbates into a PLA matrix, leads to a noticeable increase in elongation at break, from 4.0% (neat PLA) up to values around 180%. The plasticization efficiency was assessed by the decrease in the glass transition temperature (Tg), from 61.0 ºC (neat PLA) down to such los values of 29.5 ºC, and 36.6 ºC, for plasticized PLA formulations with 30 wt% Tween® 20, and 30 wt% Tween® 80, respectively. Moreover, due to the high molecular weight of polysorbates, they are not highly volatile, which allows processing PLA by conventional extrusion and injection molding without plasticizer volatilization. This works widens the industrial applications of polysorbates, as cost-effective, highly efficient and environmentally friendly plasticizers for PLA with enhanced toughness. [ABSTRACT FROM AUTHOR]

Heterostructured ferritic steels with bimodal-grained lamellar (BG-L) and ultrafine-grained lamellar (UFG-L) microstructure were prepared through a warm deformation process. The BG-L steel exhibits enhanced mechanical properties compared to conventional quenched and tempered (QT) steel. While the UFG-L steel demonstrates an outstanding combination of strength, ductility, and toughness. Furthermore, the UFG-L steels exhibit no ductile-to-brittle transition (DBT) from room temperature (RT) to liquid nitrogen temperature (LNT) and the Charpy impact energy remains as high as 314 J at LNT. The enhanced toughness at LNT can be attributed to the crack-arrester mechanism caused by grain-boundary delamination. [ABSTRACT FROM AUTHOR]

Epoxy resins, ubiquitous and indispensable thermosetting material in various industries, suffer from the resistance to crack initiation, poor ductility, and irreparable permanent cross‐linked network, which hinder their utilization in high‐performance applications and are detrimental to the development of a sustainable economy. However, achieving the trade‐off between toughness, robustness, and reprocessability of epoxy resins remains a formidable challenge. Herein, an epoxy resin that combines ultratoughness, robustness, and reprocessability by incorporating a hierarchical crosslink structure embedded in a transesterification network is reported. The construction of hierarchical coordination structures facilitates formation of dense nano‐hard domains, enabling enhancement of both strength and toughness at multilength scales. As a result, the epoxy resin, integrating covalent adaptable networks with sacrificial non‐covalent networks, exhibits exceptional elongation at break (280%), modulus (1.8 GPa), stress at break (56.3 MPa), and tensile toughness (142 MJ m−3), showcasing its excellent endurance and ability to undergo multiple reprocessability. The application of this epoxy resin in carbon fiber‐reinforced polymer composites further underscores its potential as the resulting HCEV‐CFRPs exhibit unprecedented tensile properties and facilitate multiple non‐destructive recycling of high‐value carbon fiber under mild conditions. This research provides novel design principles for recyclable and high‐performance materials that combine strength and toughness. [ABSTRACT FROM AUTHOR]

The brittleness and limited plastic deformation of ceramics restrict their applications. In this work, the effects of pristine (CNT P), functionalized (CNT OH , CNT COOH) and silanized MWCNTs on the mechanical properties of Silicon Carbide obtained by pyrolyzing polycarbosilane SMP-10 were studied. Functionalization with 3-glycidoxypropyltrimethoxy was analyzed through dispersion stability, zeta potential, and EDS analyses, revealing increased silicon content and colloidal stability in silanized MWCNTs. However, silanized MWCNTs led to reduced mechanical properties in composites, while untreated MWCNTs (CNT P , CNT OH , CNT COOH), showed a substantial increase in modulus by 74.2 %, 86.9 %, and 30.5 %, respectively. The observed enhancement in mechanical properties exceeded the outcomes predicted by the rule of mixtures, suggesting notable morphological changes induced by MWCNTs. Potential underlying factors including toughening mechanisms and changes in porosity were evaluated and discussed in depth. Composites with untreated MWCNTs showed nearly a two-fold increase in fracture toughness. This work shows a streamlined approach for the development of ceramic nanocomposites (CNCs), achieving significant improvement in mechanical properties through pyrolysis, surpassing traditional methods reliant on densification processes. These findings demonstrate the substantial potential of CNCs, enhancing their suitability for advanced engineering applications. [ABSTRACT FROM AUTHOR]

Traditional epoxy resins are of technological significance for structural adhesives and composite materials, as well as many others. However, brittleness limits its further development, and achieving a combination of toughness and rigidity in epoxy networks remains a great challenge. In this work, we designed and synthesized low-temperature curable, tough and repairable epoxy networks via hindered urea bond (HUB) crosslinking strategies. Mechanical testing revealed that the material exhibited simultaneously improved toughness and stiffness, and specifically, tensile strength, elongation at break, and toughness were able to reach 78.2 MPa, 8.61%, and 4.63 MJ · m−3, respectively. More importantly, the dynamic exchange of HUB dispersed between polymer chains enables HUB crosslinked epoxy with thermal-triggered reparability and recyclability. In addition, thermal properties, chemical stability and water resistance of toughened epoxy samples were also characterized. This work provides a practical guidance for the exploration of high-performance epoxy with the potential to be extended to other polymers. [ABSTRACT FROM AUTHOR]

A major challenge in the application of ceramic materials is a trade‐off between strength and toughness. In this work, hierarchically structured ceramic coatings (HSCCs) are fabricated to address this challenge. HSCCs feature a dual‐layer micron‐scale structure built on a “brick‐mortar” nanoscale structure, which is achieved by changing the crystalline and amorphous phase ratio during plasma electrolytic oxidation (PEO). It is found that HSCCs with homogeneous interfaces exhibit high thermal stability up to 700 °C and a 65% improvement in shear strain resistance compared to conventional crystalline coatings (CCCs). This improvement is attributed to the stabilizing effect of atoms on the boundaries of the enhancement phase and the facilitating effect on the deformation of the compliant phase. The hierarchical structure effectively leverages the plasticity of the compliant phase and the strength of the enhancement phase facilitated by the homogeneous interface. This work proposes a feasible approach for improving the toughness of ceramic functional composites and mitigating their susceptibility to brittle fracture. [ABSTRACT FROM AUTHOR]

The effect of equal channel angular pressing combined with inter‐pass and post‐process annealing on the microstructure and mechanical properties of the Al‐7075 alloy has been studied. The samples underwent successful equal channel angular pressing for three passes using the Bc route. The most significant changes in mechanical properties were observed after the first pass. Despite an 88 % reduction in grain size, the hardness of the alloy increased by 45 % and the fracture toughness decreased by 75 %. Post‐process annealing was found to be an effective method for enhancing the alloy's toughness. Annealing the one‐pass sample at 310 °C resulted in a 33 % increase in fracture toughness; from 15.8 J to 21.02 J. Inter‐pass annealing had a lesser impact on improving fracture toughness compared to post‐process annealing. It can be concluded that a balanced combination of strength and toughness can be achieved by utilizing a combination of equal channel angular pressing and inter‐pass or post‐process annealing. Examination of the fracture surfaces of the samples revealed intragranular fractures, with the annealed samples exhibiting higher energy absorption during impact and better toughness compared to the non‐annealed sample. [ABSTRACT FROM AUTHOR]

Material selection is the main challenge in the drone industry. In this study, hardness, abrasive wear, impact resistance, tensile strength, and durability (frost resistance and accelerated ageing) were identified as important characteristics of drone materials. The additive manufacturing technology was used to produce the drone leg specimens and prototype. The suitability of PETG as a primary filament material in the design of the drone leg was investigated. Nine series were printed with different raster lines (0.1, 0.2 and 0.3 mm) and infill densities (30, 60 and 90%). Printed specimens were annealed in salt and alabaster, as well as immersed in liquid nitrogen. Series with raster line-infill densities of 0.1–30, 0.3–30, 0.1–90 and 0.3–90 were identified as the most interesting ones. Thermally treated specimens had better mechanical and durability properties, and infill density was found to be the most important printing parameter. Specimen annealed in salt with a raster line of 0.1 mm and infill density of 90% had the best results. Since ABS is the most common material used for drone leg production, its properties were compared with the PETG specimen, which showed the best properties. The potential of PETG as an alternative material was proven, while the flexibility, productivity and suitability of the leg drone design were additionally confirmed. [ABSTRACT FROM AUTHOR]

In this study, we used the depth-sensing indentation technique to determine the cracking resistance of different PVD hard coatings deposited on tool steel substrates. By comparison, with the load–displacement curves, measured at the sites of carbide inclusion and a tempered martensite matrix in the D2 tool steel substrate surface, we observed different fracture mechanisms on TiAlN hard coating prepared by sputtering. Additional information about the deformation and fracture phenomena was obtained from the SEM images of FIB cross-sections of both types of indents. We found that the main deformation mechanism in the coating is the shear sliding along the columnar boundaries, which causes the formation of steps on the substrate surface under individual columns. Using nanoindentation test, we also analyzed the cracking resistance of a set of nl-(Cr,Al)N nanolayer coatings with different Cr/Al atomic ratios, which were sputter deposited in a single batch. From the indentation curves, we determined the loads (Fc) at which the first pop-in appears and compared them with the plasticity index H3/E2. A good correlation of both parameters was found. We also compared the indentation curves of the TiAlN coating, which were prepared by cathodic arc evaporation using 1-fold, 2-fold and 3-fold rotation of the substrates. Additionally, on the same set of samples, the fracture toughness measurements were performed by micro-cantilever deflection test. The impact of growth defects on the cracking resistance of the hard coatings was also confirmed. [ABSTRACT FROM AUTHOR]

Let β > 0 . Motivated by the notion of jumbled graphs introduced by Thomason, the expander mixing lemma and Haemers's vertex separation inequality, we say that a graph G with n vertices is a weakly (n , β) -graph if | X | | Y | (n - | X |) (n - | Y |) ≤ β 2 holds for every pair of disjoint proper subsets X, Y of V(G) with no edge between X and Y. It is an (n , β) -graph if in addition X and Y are not necessarily disjoint. Using graph eigenvalues, we show that every graph can be an (n , β) -graph and/or a weakly (n , β) -graph for some specific value β . For instances, the expander mixing lemma implies that a d-regular graph on n vertices with the second largest absolute eigenvalue at most λ is an (n , λ / d) -graph, and Haemers's vertex separation inequality implies that every graph is a weakly (n , β) -graph with β ≥ μ n - μ 2 μ n + μ 2 , where μ i denotes the i-th smallest Laplacian eigenvalue. This motivates us to study (n , β) -graph and weakly (n , β) -graph in general. Our main results include the following. (i) For any weakly (n , β) -graph G, the matching number α ′ (G) ≥ min 1 - β 1 + β , 1 2 · (n - 1) . If in addition G is a (U, W)-bipartite graph with | W | ≥ t | U | where t ≥ 1 , then α ′ (G) ≥ min { t (1 - 2 β 2) , 1 } · | U | . (ii) For any (n , β) -graph G, α ′ (G) ≥ min 2 - β 2 (1 + β) , 1 2 · (n - 1). If in addition G is a (U, W)-bipartite graph with | W | ≥ | U | and no isolated vertices, then α ′ (G) ≥ min { 1 / β 2 , 1 } · | U | . (iii) If G is a weakly (n , β) -graph for 0 < β ≤ 1 / 3 or an (n , β) -graph for 0 < β ≤ 1 / 2 , then G has a fractional perfect matching. In addition, G has a perfect matching when n is even and G is factor-critical when n is odd. (iv) For any connected (n , β) -graph G, the toughness t (G) ≥ 1 - β β . For any connected weakly (n , β) -graph G, t (G) > 5 (1 - β) 11 β and if n is large enough, then t (G) > 1 2 - ε 1 - β β for any ε > 0 . The results imply many old and new results in spectral graph theory, including several new lower bounds on matching number, fractional matching number and toughness from eigenvalues. In particular, we obtain a new lower bound on toughness via normalized Laplacian eigenvalues that extends a theorem originally conjectured by Brouwer from regular graphs to general graphs. [ABSTRACT FROM AUTHOR]

The high residual stress and low toughness of ceramic matrix composite/metallic brazed joints poses severe challenges for the stable operation of high-speed aircraft under harsh conditions. This article innovatively tackles this issue with electrophoretic deposition (EPD), creating a CNT covered Cu foam composite interlayer for brazing C f /SiC and Nb with an Ag–Cu–Ti alloy filler. A layer of mass ratio-controllable and percolated CNTs was physically adsorbed on the surface of the Cu foam substrate. EPD time was systematically investigated for its impact on the microstructure and mechanical properties of the joints. Results indicate that during brazing, the CNTs reacted with the active Ti element, transforming into ultrafine TiC grains with particle sizes ranging from 6 to 16 nm. These were dispersed evenly in the Ag solid solution. The elastic recovery rate of the cluster regions showed an increase of 123 % compared to the Ag solid solution, showing improved toughness of the seam. When the EPD time was 80 min, the shear strength of the joint produced with the composite interlayer reached 128.6 MPa, a 69 % increase over the directly brazed joint. Moreover, the fracture location of the joint shifted from the brazed seam towards the interior of the bulk C f /SiC. Additionally, finite element analysis was utilized to confirm a significant decrease in residual stresses within the joint, and verified the findings. [ABSTRACT FROM AUTHOR]

Overcoming the hardness‐toughness trade‐off in diamonds attracts much interest in physics, chemistry, materials science, and engineering. Recently synthesized nanotwinned diamond composite exhibits massive enhancement in fracture toughness without sacrificing its unprecedented Vickers hardness [Y. Yue et al., Nature 582, 370 (2020)]. Several mechanisms for the toughness enhancement are unveiled based on the edge‐cracked models while the mechanism from Vickers indentation has remained elusive. Here, the energy of nanotwinned diamonds, diamond polytypes, and diamond composites is systematically investigated from Vickers indentation simulation. The results show diamond structures dissipate energy by interface migration, accompanied by the phase transformation from diamond polytypes to the cubic diamond (3C diamond). By tuning the density and distribution of interfaces, the dissipated energy of the diamond is increased to more than twice that of a single‐crystal 3C diamond. This work complements the established mechanisms and provides a universal strategy for toughening diamonds and related materials. [ABSTRACT FROM AUTHOR]

Covalent polymer networks find wide utility in diverse engineering applications owing to their desirable stiffness and resilience. However, the rigid covalent chemical structure between crosslinking points imposes limitations on enhancing their toughness. Although the incorporation of sacrificial chemical bonds has shown promise in improving toughness through energy dissipation, composite networks struggle to maintain both rapid recovery and stiffness. Consequently, a significant challenge persists in achieving a covalent network that combines high strength, stiffness, toughness, and fast recovery performance. To address this challenge, we propose a novel sacrificial structure termed “sacrificial conformation.” In this approach, β‐cyclodextrin is covalently embedded into the network skeleton as the sacrificial conformation element. Compared to traditional covalent networks (LCN), well‐designed cyclodextrin‐embedded covalent network (CCN) exhibit a 100‐fold increase in Young's modulus and a 60‐fold increase in toughness. Importantly, CCN maintains excellent elasticity, ensuring swift recovery after deformation. This sacrificial conformational strategy enables efficient energy dissipation without necessitating the rupture of chemical bonds, thereby overcoming the limitations of traditional approaches. This advancement holds great promise for the design and fabrication of advanced elastomers and hydrogels with superior mechanical properties and dynamic behavior. [ABSTRACT FROM AUTHOR]

The effect of SiC content (10 vol%, 20 vol% and 30 vol%) and sintering temperature (1800 °C, 1900 °C and 2000 °C) on the microstructure and mechanical properties of high entropy boride-silicon carbide (HEB-SiC) composites were systematically investigated in this work. The densification was gradually increased with the increase of SiC content and sintering temperature. More specially, the densification of HEB-30 vol% SiC composite obtained at 2000 °C was as high as 99.1 %. As for the mechanical properties, the dense HEB-30S-2000 composite possessed the highest fracture toughness (5.24 MPa m1/2) and Vickers hardness (28.5 GPa). The above significantly enhanced fracture toughness was closely pertained to the fracture modes adjusting. In details, after the addition of SiC, the branching and bridging of crack, the rupture of large SiC grain, and the deflection of crack existing near the HBE matrix and SiC particles jointly promote the improvement of fracture toughness. Besides, the Vickers hardness increased linearly with the relative density increasing. A simplified equation was established, which could effectually reflect the linear connection between the Vicker hardness and relative density (SiC content) of HEB-SiC composites. It will certainly play an important guiding role in the further development of HEB-SiC composites. [ABSTRACT FROM AUTHOR]

While blending with flexible polymers has been a commonly employed strategy to enhance the toughness of polylactic acid (PLA), it's still a great challenge to avoid the sacrifice of tensile strength at the same time. In this work, we demonstrate a promising route to simultaneously improve the strength and toughness of PLA by compounding PLA with poly(ε‐caprolactone) (PCL) and PLA grafted multi‐walled carbon nanotubes core‐shell nanofiller (MWNT‐PCLPLA) via a two‐step ring‐opening polymerization and have analyzed the strengthening and toughening mechanism through molecular dynamics simulation. The double polymer layers of MWNT‐PCLPLA effectively improve the interfacial interaction between MWNTs and the matrix, in which the outer PLA layer has the same molecular structure with the matrix and facilitates stress transfer, while the flexible PCL layer can absorb energy through self‐deformation and induce local plastic deformation of the matrix. When the content of MWNTs was only 1 wt%, the strength and elongation at break of PLA/MWNT‐PCLPLA nanocomposites were increased by 47.92% and 690.11% compared to neat PLA. Furthermore, the toughness of nanocomposites reached 11.93 MJ/m3, which is about 16 times that of neat PLA. This novel core‐shell nanofiller with double polymer layers is expected to be further applied in other polymer systems. Highlights: A core‐shell nanofiller with double polymer layers was synthesized.Improved dispersion and interfacial compatibility of nanofillers in matrix.The crystallization ability of PLA was improved by functionalized MWNTs.Simultaneously improved strength and toughness of PLA/MWNT‐PCLPLA nanocomposite. [ABSTRACT FROM AUTHOR]

In this paper, the influence of Cr element on the mechanical properties of welded joints of gas-shielded solid wire used in oil and gas long-distance pipelines was studied by means of tensile test, impact test, and hardness test, and the microstructure and crack propagation path of weld were characterized by means of an optical microscope, scanning electron microscope, and electron backscattering diffraction. The results show that with the addition of Cr, the strength and toughness of the weld are significantly improved, in which the tensile strength is increased from 607 MPa to 656 MPa, and the impact toughness is increased from 126.37 J to 223.79 J. The proportion of the ferrite side plate in the weld structure is reduced by about 20%, and the effective grain size of acicular ferrite is reduced by about 15%. The reason is that the addition of the Cr element improves the hardenability of the weld structure, inhibits the formation of the ferrite side plate, and promotes the effective refinement of acicular ferrite, which increases the proportion of high-angle grain boundaries in the weld, effectively hindering the crack propagation, improves the crack propagation work, and thus improves the strength and toughness of the weld. [ABSTRACT FROM AUTHOR]

Designing heat‐resistant thermosets with excellent comprehensive performance has been a long‐standing challenge. Co‐curing of various high‐performance thermosets is an effective strategy, however, the traditional trial‐and‐error experiments have long research cycles for discovering new materials. Herein, a two‐step machine learning (ML) assisted approach is proposed to design heat‐resistant co‐cured resins composed of polyimide (PI) and silicon‐containing arylacetylene (PSA), that is, poly(silicon‐alkyne imide) (PSI). First, two ML prediction models are established to evaluate the processability of PIs and their compatibility with PSA. Then, another two ML models are developed to predict the thermal decomposition temperature and flexural strength of the co‐cured PSI resins. The optimal molecular structures and compositions of PSI resins are high‐throughput screened. The screened PSI resins are experimentally verified to exhibit enhanced heat resistance, toughness, and processability. The research framework established in this work can be generalized to the rational design of other advanced multi‐component polymeric materials. [ABSTRACT FROM AUTHOR]

A novel phenylethynyl-terminated siloxane-containing ortho -hydroxy polyimide (O-SPI) was synthesized and physically blended with thermoplastic polyimide (PI) to enhance both the thermal and mechanical properties of polyimide, addressing the growing demand for high-performance materials in harsh environments. The blend underwent conversion to semi -Interpenetrating Polymer Networks (semi -IPNs) and benzoxazole structures through thermal curing of reactive phenylethynyl groups and thermal rearrangement of ortho-hydroxy imide units. The trends in thermal and mechanical properties were investigated in relation to the chemical structures and varying mass fraction of O-SPI. The covalent incorporation of semi -IPNs and rigid benzoxazole structures restrict segmental motion while the backbone linkage confers the toughness of the blends. These synergistic effects insure the cured blends with high glass transition temperatures (472.51°C) and tensile strength (117.81 MPa) simultaneously, demonstrating their potential for applications in challenging conditions. [ABSTRACT FROM AUTHOR]

Glass coatings find application across diverse fields, offering chemical resistance, insulation, and hardness to substrates. Toughness enhancement of glass coatings is strongly required to maintain these functions in the practical applications. In this study, we propose a novel approach to improve fracture toughness of glass coating by incorporating silver particles into it prepared via the sol-gel method. Samples with 0–2.0 vol% of 73 nm and 730 nm Ag particles in the precursor solution were obtained. The resulting samples exhibited high transparency, minimal change in Young's modulus, and considerably improved fracture toughness. At 73 nm and 730 nm, the maximum fracture toughness occurred at 0.5 vol% and 1.0 vol%, respectively, with a 1.4- and 1.8-fold increase compared to the original coating. This approach shows promise for enhancing glass coating toughness with minimal additive amounts and negligible loss of coating properties. [ABSTRACT FROM AUTHOR]

Copyright of China Rubber Industry is the property of Editorial Office of China Rubber Industry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Poly(butylene succinate) (PBS) was melt-blended with paramylon based mixed ester, paramylon propionate hexanoate (PaPrHe) and characterized for its morphology, thermal and mechanical properties. The PBS/PaPrHe blends were found to be immiscible throughout the loading range of PaPrHe (10–90 wt%), with individual glass transition peaks. Due to the immiscibility, there was phase separation observed in the bulk, evident by sea-island morphology. However, further observation of the micro-structure revealed that, in low PaPrHe loading (10–30 wt%), there was a micron to sub-micron order distribution of PBS particles and partially miscible PBS/PaPrHe phase. On increasing the PaPrHe to 50 wt% and beyond, the sub-micron scale domains fused to form a co-continuous morphology. As a result, the impact strength of PBS increased from 6.6 to 16.4 kJ/m2 in the 50/50 blend. Under tensile loading, the strength at break and elongation decreased after the introduction of less-flexible PaPrHe particles in the blend. This could be countered by uniaxially stretching the blended films with 10–30 wt% PaPrHe, after which the tensile strength increased by up to 380% (from 33–52 MPa to 165–200 MPa) compared to the unstretched films, attributable to the increased degree of orientation of the molecular chains. In terms of thermal processability, all the blend ratios had high thermal degradation temperature (>350 °C), higher than the melt-flow temperature (124–133 °C) providing a wide processing window. Overall, PBS/PaPrHe blend is a novel bio-based blend with properties suitable for packaging, mulching, and related applications. [ABSTRACT FROM AUTHOR]

Recycling end-of-life tires (EOLT) presents a sustainable solution for addressing a major waste issue in many countries. This study focuses on the reuse of EOLT as construction materials, particularly in the form of EOLT-based rubberised concrete. However, several research gaps hinder the understanding of this construction material for implementation into practice. This study delves into key parameters, including admixture composition, aging, thickness, rubber distribution, and surface roughness, which play pivotal roles in designing and implementing rubberised concrete noise barriers. The paper presents the results of investigations into the performance of fibre-reinforced rubberised concrete when entrained with air, shedding light on flexural toughness and post-crack behaviour. The effects of incorporating fly ash and ground granulated blast furnace slag (GGBFS) as cement replacements are also examined. The acoustic performance of fibre-reinforced rubber concrete is studied, including the impact of sample conditioning (surface saturated dry or dry). The results indicate that air-entraining admixtures, the replacement of coarse sand with tire-derived rubber shreds, and the inclusion of recycled polypropylene fibre significantly enhance the mechanical and acoustic properties of the concrete. For instance, compressive strength improves by 43%, flexural strength by 120% and acoustic performance nearly twice, while water absorption and volume of permeable voids remain relatively unaffected. This study suggests an optimized sustainable mix design with rubber replacing more than 75% of the aggregate volume. It underscores the potential of EOLT-based rubberised concrete as an environmentally responsible construction material, offering enhanced performance across multiple domains, including noise attenuation barriers. [ABSTRACT FROM AUTHOR]

Copyright of Paint & Coatings Industry (0253-4312) is the property of Paint & Coatings Industry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ti--10V--2Fe--3Al alloys exhibit shape memory (SM) and reverse shape memory (RSM) effects. When an alloy sample that has been strained by external force at room temperature is heated, the strain recovers and SM effect develops at around 300, but as the temperature increases further, the shape changes in the opposite direction due to RSM effect at around 450. This RSM effect has potential applications in forming processes such as thin--walled pipes, but has the disadvantage that the RSM treatment makes the material very brittle. Therefore, in this study, a heat treatment to restore toughness while maintaining the shape after forming was investigated. The alloy quenched from 1050 had a microstructure consisting of a β matrix phase and αAA--martensite (αAAMq). Differential scanning calorimetry (DSC) results showed that the continuous heating process occurred in the following order: αAAMq → β reverse transformation, ω formation, ω disappearance, thermally induced αAAiso phase formation, α precipitation and α → β transformation. Ageing at 300, where the SM effect appears, caused significant embrittlement due to the formation of the ageing ω phase. Ageing treatment at 450, where the RSM effect is obtained, resulted in the formation of a fine α phase, which also caused significant embrittlement. On the other hand, additional aging at 600 for 1.8 ks after RSM treatment significantly improved the toughness and produced material properties comparable to aerospace material specifications. It was found that the embrittlement in the RSM treatment was due to the precipitation of fine α phase, and that the growth of α phase with a width of about 0.2µm or more was required for toughness recovery. It was also found that the specimen shape formed by the RSM treatment hardly changed after the additional heat treatment of 1.8 ks at 600. [ABSTRACT FROM AUTHOR]

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Heterostructured ferritic steels with bimodal-grained lamellar (BG-L) and ultrafine-grained lamellar (UFG-L) microstructure were prepared through a warm deformation process. The BG-L steel exhibits enhanced mechanical properties compared to conventional quenched and tempered (QT) steel. While the UFG-L steel demonstrates an outstanding combination of strength, ductility, and toughness. Furthermore, the UFG-L steels exhibit no ductile-to-brittle transition (DBT) from room temperature (RT) to liquid nitrogen temperature (LNT) and the Charpy impact energy remains as high as 314 J at LNT. The enhanced toughness at LNT can be attributed to the crack-arrester mechanism caused by grain-boundary delamination.

This study investigates the tensile and impact property of TRIP (transformation-induced plasticity)-aided steel with different retained austenite (RA) stability at different temperatures. The RA stability of experimental steels processed by hot rolling-coiling at 450 °C, short tempering and long duration tempering followed the sequence: un-temper (C450)

Equal‐period modulated metal/ceramic multilayers have shown promise in enhancing the toughness of ceramic thin films. However, this toughness enhancement typically comes at the sacrifice of hardness, limiting their potential applications. To tackle this issue, this study designed and fabricated two gradient‐structured multilayer variations using Ta/TaB2: one with a higher ceramic layer fraction near the surface (M2) and the other with a converse structure (M3). A conventional equal modulation period Ta/TaB2 multilayer film (M1) served as a reference. M2 exhibited superior performance, with a 30% hardness increase and significant toughness enhancement compared to M1. Conversely, M3 experienced failure due to excessive thermal stress from its unique gradient structure. Finite element simulations revealed that M2's structure could alleviate in‐plane stress and enhance loading uniformity, thus enhancing the film's toughness. These findings suggest that a well‐designed gradient structure holds promise for concurrently improving the hardness and toughness of metal/ceramic multilayer films. [ABSTRACT FROM AUTHOR]

Biodegradable polylactic acid (PLA) melt-blown nonwovens are attractive candidates to replace non-degradable polypropylene melt-blown nonwovens. However, it is still an extremely challenging task to prepare PLA melt-blown nonwovens with sufficient mechanical properties for practical application. Herein, we report a simple strategy for the large-scale preparation of biodegradable PLA/poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) melt-blown nonwovens with high strength and excellent toughness. In this process, a small amount of PHBV is added to PLA to improve the latter’s crystallization rate and crystallinity. In addition, when the PHBV content increases from 0 to 7.5 wt%, the diameters of the PLA/PHBV melt-blown fibers decrease significantly (with the proportion of nanofibers increasing from 7.7% to 42.9%). The resultant PLA/PHBV (5 wt% PHBV) melt-blown nonwovens exhibit the highest mechanical properties. The tensile stress, elongation, and toughness of PLA/PHBV (5 wt% PHBV) melt-blown nonwovens reach 2.5 MPa, 45%, and 1.0 MJ·m−3, respectively. More importantly, PLA/PHBV melt-blown nonwovens can be completely degraded into carbon dioxide and water after four months in the soil, making them environmentally friendly. A general tensile-failure model of melt-blown nonwovens is proposed in this study, which may shed light on mechanical performance enhancement for nonwovens.

Rock breaking has always been a challenging problem that must be solved in projects such as excavating mountains, drilling wells, and constructing railways. Among the rock-breaking cutter steels, AISI H13 steel and wear-resistant high manganese steel have become the best choices. From the characteristics and failure modes of the two, rock-breaking cutter steels should simultaneously have high strength, high toughness and high wear resistance to avoid short-term fracture/damage and cost increase. Analyzing the problems existing in the molding process of rock-breaking cutter steels such as die casting, forging, and hot stamping, traditional strengthening technologies such as alloying optimization, heat treatment, and surface treatment can achieve certain performance enhancement. After reaching the limits of traditional strengthening technologies, a series of nanoparticle strengthening technologies came into being. The selection, addition amount, and addition method of nanoparticles all affect the microstructure, mechanical properties and wear. To this end, this article summarizes the research progress and challenges of rock-breaking cutter steels, and discusses traditional strengthening technologies and mainstream nanoparticle strengthening technologies. It provides a reference for the future development of high-quality and high-performance rock-breaking cutter steels, with aim to simultaneously expand their application potentials to other fields.

In the Jakarta area, the extensive replacement of green lands with concrete buildings have restricted the opportunity for family land ownership dedicated to conservation. This community service aims to develop motivation and a culture of planting to increase the knowledge, awareness, willingness, and ability of Family Welfare Empowerment (FWE) cadres and preschool teachers to preserve a culture of love for the environment and support family food security. The participants in this community service activity are FWE cadres and preschool teachers from the Jatinegara Kaum village. Conducted in August 2022 at the Child-friendly Integrated Public Space in Jatinegara Kaum, the project utilized the Participatory Action Research (PAR) method. Through descriptive analysis of the discussions, it was found that FWE cadres and preschool teachers actively engaged and showed their capability as pivotal agents in strengthening community resilience. This successful engagement underlines the potential for ongoing collaborative activities in community education and sustained support for the FWE cadres and preschool teachers.

In order to improve the impact toughness of polyamide 1012 (PA1012) by reducing the amount of hydrogen bonding resulting from PA1012 itself, 3-pentadecylphenol (PDP) was considered to be added into PA1012 using melting extrusion. The hydrogen bonding interaction between PA1012 and PDP was characterized by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR). The effects of PDP on the crystallization, melting process, and mechanical behavior of PA1012 were tested in detail. The results show that the PDP can reduce the temperature of PA1012 crystallization and melting but it can significantly improve elongation at break and impact toughness. The notched impact strength of the PA1012/PDP composites containing 20 wt% PDP reached to 70.6 kJ·m–2, which is about seven times that of the neat PA1012. The effects of PDP on PA1012 properties is ascribed to hydrogen bonding interaction between hydrogen bonding between phenol hydroxyl groups and amino groups on PA1012 chains. The deduction was also verified by adding acetylated 3-pentadecylphenol (APDP) to modify PA1012. It is believed the research will open up new prospects for the wide application of PA1012 toughening.

The development of rigid yet fatigue‐resistant elastomers possess a critical challenge, necessitating materials capable of enduring substantial mechanical loads while maintaining structural integrity through cycles of deformations. Despite soft materials achieving a fatigue threshold of ∼1000 J m−2, their modulus, typically ∼1 MPa, restricts their applications. This study presents a breakthrough in designing rigid, fatigue‐resistant elastomers by controlling nanosheet orientation within the network using a shear force strategy. The elastomers achieve a high fatigue threshold of 1900 J m−2 while maintaining a high elastic modulus of 8 MPa. These superior mechanical properties are attributed to the synergistic effects of microscale alignment of nanosheets and robust interfacial bonding between the polymer chains and nanosheets at the nanoscale. When the nanosheet volume fraction is below the percolation threshold, well‐dispersed nanosheets transfer load effectively through strong interfacial bonding with the polymer, significantly suppressing fatigue crack propagation. Conversely, above the percolation threshold, agglomerated nanosheets create defects in the matrix, reducing load‐bearing capacity. The innovative elastomers demonstrate potential for a wide range of applications, including automotive components, actuators, and stretchable electronic devices, where high mechanical stability and load‐bearing capacity are essential. [ABSTRACT FROM AUTHOR]

High mechanical strength, toughness, and fatigue resistance are essential to improve the reliability of conductive hydrogels for self‐powered sensing. However, achieving mutually exclusive properties simultaneously remains challenging. Hence, a novel directed interlocking strategy based on topological network structure and mechanical training is proposed to construct tough hydrogels by optimizing the network structure and modulating the orientation of molecular chains. Combining Zn2+ crosslinked cellulose nanofibers (CNFs) and a polyacrylamide‐poly(vinyl alcohol) double‐network, the unique interlocked‐network structure exhibits an enhanced toughening effect due to hydrogen bonding and metal‐ligand interactions. The aligned nanocrystalline domains achieved by training further contribute to an increase in the toughness and fatigue thresholds. This innovative approach synergistically enhances the mechanical properties of the nano‐conductive hydrogel, achieving a maximum tensile strength of 4.98 MPa and a toughness of 48 MJ m−3. Notably, the CNFs template with anchored polyaniline, when oriented through mechanical training, forms a unique directional conductive pathway, which significantly enhances the power output performance. Besides, a motion recognition system based on a self‐powered sensing device is designed with the assistance of deep learning techniques to accurately identify human motion behaviors. This work showcases a potentially transformative flexible electronic material for self‐powered sensing systems and intelligent recognition systems. [ABSTRACT FROM AUTHOR]

This study investigates the effect of incorporating polyethylene terephthalate (PET), polyetherimide (PEI), and polyether‐ether‐ketone (PEEK) thermoplastic films in melt form as interlayers to toughen carbon fiber/epoxy composites. The addition of melt‐infused PET, PEI, and PEEK film into carbon fiber/epoxy composite enhanced the mode‐I interlaminar fracture toughness (ILFT) by 60%, 156%, and 284%, respectively. The primary toughening mechanisms found were plastic deformation and mechanical interlocking through fiber bridging, which left fiber imprint traces on the fracture surface. The mode‐II ILFT of PET, PEI, and PEEK film interleaved laminates was improved by 80%, 188%, and 96%, respectively. Plastic deformation was observed to be the principal toughening mechanism. Notably, these enhancements in ILFT were achieved while simultaneously increasing interlaminar shear strength. These findings show the role of hot‐melt‐infused PET, PEI, and PEEK thermoplastic films in the improvement of ILFT of composites which is crucial in the design of damage‐tolerant composite structures. Highlights: Composites were interleaved with PET, PEI, and PEEK films via melt‐infusion.Mode‐I and mode‐II ILFT were significantly enhanced, up to 284% for PEEK.Failure exhibited plastic deformation, extensive fiber bridging, and pull‐out.Melt‐infusion created complex, mechanically interlocked interfaces. [ABSTRACT FROM AUTHOR]

FeCrAl alloy is considered a promising material for light water reactor fuel cladding due to its excellent elevated temperature oxidation resistance and radiation performance. The effects of 0.21 wt% Nb or 0.23 wt% La additions on the microstructure, second phase, yield strength and toughness of FeCrAl alloy are studied. The morphology and number fraction of inclusions in FeCrAl alloys are analyzed. The addition of 0.21 wt% Nb in FeCrAl alloy promotes the precipitation of nanoscale (Fe,Cr)2(Nb,Ti) Laves phase and refining grain size. The addition of La‐modified Al2O3 and MgO·Al2O3 inclusions to La2O3 and LaS, and La2O3 is favorable to promote the heterogeneous nucleation of α‐Fe. The fracture mode of the FeCrAl alloy with 0.21 wt% Nb or 0.23 wt% La transitions from dimple fracture and quasi‐cleavage fracture to dimple fracture, in comparison with Nb‐free or La‐free FeCrAl alloy. Nb and La additions improve the yield strength and toughness of FeCrAl alloy. The addition of Nb exhibits a more pronounced strengthening effect on FeCrAl alloy compared with the addition of La. [ABSTRACT FROM AUTHOR]

To investigate the improvement effect and mechanism of the combined of basalt fiber and fly ash on the tensile performance of cementitious soil, basalt fibers of various contents, lengths and fly ash of different contents were selected and incorporated into the cement soil consisting of weak soil in mountainous areas. A series of splitting tensile tests and electron microscopy scanning tests were conducted to study the strength, deformation, toughness, and microscopic mechanism of action. The results indicate that basalt fiber length 6 mm and doping amount 0. 6%, and fly ash content 12% are the combined effect of the two has the best effect on improving the tensile performance and toughness of cement-soil. Compared with ordinary cement-soil, its tensile strength, residual strength, peak strain, and tensile absorption energy have increased by 40. 55%, 134. 68%, 40. 81%, and 132. 22%, respectively. The 18 mm fibers deteriorate the tensile properties of cementitious soil. The mechanism is that fibers reinforce the weak surface inside the cement soil, bear and transmit tensile stress, making the internal stress of the cement soil more uniform. Fly ash pearl particles can fill the pores inside the cement soil, making the cement soil particles fully bond with fibers, and enhancing the integrity of the sample. [ABSTRACT FROM AUTHOR]

Developing a stiffness-toughness balance, low-cost, and biodegradable PLA composite is an effective strategy for improving product market competitiveness, reducing dependence on petroleum-based resources and protecting the environment. Rice husk (RH) is extensively used as a filler in polymers, but the addition of too much rice husk into PLA has damaged the toughness of the composite. In this work, fully biodegradable composites with a stiffness-toughness balance and low cost are successfully fabricated through melt blending of PLA, RH and acetyl tributyl citrate (ATBC), named PLAC0, PLAC3, PLAC6, PLAC9, PLAC12, PLAC15, PLAC18, PLAC20 respectively according to amount of ATBC (0phr, 3phr, 6phr, 9phr, 12phr, 15phr, 18phr, 20phr). The results show that bio-based plasticizer ATBC can improve the flowability of PLA composites, further enhancing their processability, which promotes the dispersion of RH in PLA. The impact strength and elongation at break of PLAC20 reach the value of 100 J/m and 148%, achieving an increase of 4.3 and 60.1 times compared with PLAC0, respectively. The torque rheological test shows that the maximum torque and equilibrium torque of PLAC18 decrease by about 67.4% and 63.5% respectively compared to PLAC0. This suggests a decrease in friction between PLA molecular chains, thereby increasing the fluidity of PLA composites and indicating a significant improvement in processing performance. As the ATBC amount increases, the water absorption rate of the composite progressively rises, while the contact angle steadily diminishes, resulting in the improvement for hydrophilicity, thereby broadening its potential applications. [ABSTRACT FROM AUTHOR]

Digital light processing (DLP) provides a promising avenue for constructing ceramic parts with high precision and complex shapes, yet the inherent brittleness and strength‐toughness trade‐off hinder their wide applications. Here, according to DLP 3D printing, the textured alumina ceramic components with horizontally aligned textured microstructure were successfully created by adding anisotropically shaped platelets. As a critical process in the preparation of textured ceramics, the alumina platelets were aligned horizontally during printing by using the special shear fields and forming capabilities of DLP technology. The shrinkage, density, microstructure, mechanical performance, and damage‐tolerance behavior of alumina parts with different platelet concentrations were examined, and the toughening mechanisms were investigated. The strength and toughness of ceramics with 5 vol.% platelet addition are increased by 22% and 43%, respectively, as compared with those without platelets. The improved damage tolerance capabilities were primarily ascribed to the collaborative toughening mechanisms stimulated by the platelet addition, including crack branching, crack deflection, uncracked‐ligament bridging, and platelet pull‐out, which increased the crack tortuosity and consumed more fracture energy. The strategy opens up new opportunities to design complex 3D ceramic geometries with bio‐inspired layered or textured architectures, providing optimized damage tolerance. [ABSTRACT FROM AUTHOR]

The rapid development of train transportation toward higher speed and heavier load requires superior wheel materials with high strength and toughness. Herein, a 20Mn2SiNiMo bainitic wheel steel is developed and bainitic wheels are produced. The quenching and tempering process of bainitic wheels is studied considering the bainitic ferrite content and stability of retained austenite (RA). The quenching process includes water spraying and air cooling. Proeutectoid ferrite can be suppressed during the water‐spraying process. During air cooling, the bainitic ferrite transformation is promoted and the stability of RA is improved with the extension of cooling time. Corresponding microstructure of as‐quenched steel at wheel rim is bainite with different morphologies, martensite, and RA. The evolution of RA at lower and higher tempering temperatures is dominated by carbon enrichment and carbon consumption, respectively. Yield strength of bainitic wheel steel mainly comes from body‐centered cubic phase (containing martensite and bainitic ferrite). The increase of dislocation density and the decrease of effective grain size are beneficial for yield strength improvement. Bainitic packets with various direction, deformation‐induced martensite transformation of RA, and plastic deformation all play an important role in enhancing the toughness of bainitic wheel steel. [ABSTRACT FROM AUTHOR]

Laminated composite materials are susceptible to damage, such as delamination, due to poor out-of-plane properties and inadequate adhesion at the layer interface. Using the interlayering method is an effective way to enhance resistance against delamination in these materials. However, interlayer synthesis methods have been limited and sometimes very expensive. Therefore, this study investigates the impact of novel 3D-printed polyvinyl alcohol (PVA) interlayers on the mode II interlaminar fracture toughness in glass/epoxy laminated composites. Notably, the interlayers feature a geometrical structure consisting of square cell shapes, allowing the filament to have an equal volume percentage to the resin in the interlayer. To achieve this, end-notch flexure specimens (ENF) were prepared, and the mode II interlaminar fracture toughness was calculated using the compliance-based beam method (CBBM). The specimens' crack growth resistance curve (R-curve) analysis revealed that using the desired 3D-printed interlayer increases the mode II interlaminar fracture toughness by 73%. Furthermore, the behavior of crack growth resistance in laminated composites reinforced with 3D-printed interlayer shows an increasing trend. The mode II fracture surface analysis of reinforced specimens demonstrates the influence of square cell shapes in creating shear hackles, increasing surface friction at the interface of laminated composite layers, crack pinning mechanism, and changing the direction of crack growth, ultimately leading to increased resistance to crack growth. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Nanchang University (Engineering & Technology) is the property of Nanchang University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper provides a method of assessing the toughness of augmented cables required for Ethernet technology. The use of augmented category 6 (Cat 6A) in Ethernet-enabled Internet of Things (IoT) infrastructure continues to grow due to the high demand for services requiring such configuration. The increasing demand for Cat 6A over Ethernet is due to its ability to transmit both data and power to devices used in IoT which is cost-saving. However, the availability of counterfeit and substandard cables in the market disguised as category-rated cables is of great concern to cable installers and engineers. There is also the basic problem of handling stress anticipated during installation as cables could be manipulated in the form of repeated coiling and uncoiling. Therefore, there is a need to have a method of assessing the toughness of the cables before deployment. In this paper, two Cat 6A cables from different manufacturers were selected from the market to be used as samples for the experiment. The Cat 6A cables were exposed to two rounds of coiling to imitate the handling stress anticipated during installation. The return loss and near-end crosstalk (NEXT) of the cables which are the major performance indicators were collected using the DSX-5000 cable analyzer for each of the test processes. This is to evaluate their resilience or otherwise to handling stress. Feature Selective Validation (FSV) which is a standardized method of measuring the degree of agreement between two data sets was used in this research. The results showed the cable with the lowest variations between the first and third test measurements for each of the pairs examined. The method presented showed that it can be used to assess cable measurements which can lead to objective decisions on the cables selected for deployment. [ABSTRACT FROM AUTHOR]

For the application of Ti-6Al-4V alloys in urban air mobility, safety is very important, so achieving excellent strength and toughness is essential to prevent fractures. Regarding toughness, which is a combination of strength and ductility, it is necessary to derive the optimal heat treatment conditions for this combination of Ti-6Al-4V alloy and further understand its microstructure and fracture characteristics. For this purpose, this study investigated the microstructure in terms of grain size, plate thickness, and element distribution, as well as mechanical properties, including phase hardness and tensile properties, of Ti-6Al-4V alloy subjected to solution treatment and aging (STA) heat treatment under various aging conditions. As a result, this study suggests that solution treatment followed by aging at 630 °C for 480 min can achieve approximately 26% higher toughness than the just-solution treatment process. This is because there is little difference in hardness between the equiaxed α and basketweave structures, and β plates, which contain an excessive V between α plates, function like fibers and delay fracture. [ABSTRACT FROM AUTHOR]