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With the continuous miniaturization and highly integrated development of modern electronics, thermal management materials with high thermal conductivity, good electrical insulating and flexibility are highly desired for the effective heat dissipation to maintain the reliable operations of electronic devices. However, enhancing thermal conductivity generally causes the deterioration of their mechanical properties and electrical insulation. Herein, combining the deformability of Galinstan-based liquid metal (LM) and good film-forming property of bacterial cellulose (BC), a series of thin and flexible boron nitride-based composite (BC/BNNS-LM) films was prepared via a facile vacuum-assisted filtration route. Benefiting from the directional arrangement of BNNS nanosheets, as well as gap-filling and bridging effects of deformable LM droplets, the resultant BC/BNNS-LM ternary nanocomposite film not only presents a high in-plane thermal conductivity of 66.1 W/m·K but also achieves excellent mechanical strength, flexibility and good dielectric property. These desirable properties confirm that the fabricated nanocomposite films have significant potential for effective heat dissipation in high-power-density electronics. [ABSTRACT FROM AUTHOR]

Carbon fiber (CF) is one of ideal reinforcements to hydroxyapatite (HA) owing to its unique structure, excellent biocompatibility and high mechanical properties. However, the mechanical property of CF reinforced HA (CF/HA) composites cannot be effectively improved due to the mismatch in surface properties and thermal expansion coefficients between CF and HA. In order to solve the problems, nano-hydroxyapatite (nHA) coating with different thickness was fabricated on the CF surface. The effect of the coating thickness on mechanical property of nHA-coated CF/HA composites was studied by finite element analysis. The CF with proper nHA coating thickness was subsequently used to reinforce HA. The compressive strength of nHA-coated CF/HA composites was approximately 97.3 % and 164.6 % higher than those of the uncoated CF/HA composites and pure HA ceramics, respectively. The interface properties and crack propagation were analyzed by cohesive element in the finite element analysis. The toughening mechanism of the composites included interfacial debonding, crack deflection, crack branching, and crack bridging. The mechanical properties of nHA-coated CF/HA composites were enhanced due to the strong interfacial bonding strength and reducing cracking in HA matrix. The prepared nHA-coated CF/HA composites satisfy the requirement of the mechanical properties of human load-bearing bone. It can be used to prepare cages, plates, screws, pins and other compact bone substitute parts in bone grafting. The study provided a method for construction of nHA-coated CF/HA composites with the designed properties by adjusting the nHA coating on the fiber and can be used to design other fibers reinforced ceramic matrix composites. [Display omitted] [ABSTRACT FROM AUTHOR]

A coral-like network carbon aerogel was synthesized by introducing acid-modified carbon nanofibers (a-CNF) into phenolic (PR) aerogel through chemical grafting, followed by high-temperature carbonization. The bonding interaction between a-CNF and PR was analyzed by FT-IR spectroscopy. The microstructure of a-CNF/PR composite aerogel (a-CNF/PRA) was studied by SEM and pore structure analysis. The results showed that introducing 5 wt% of a-CNF was most favorable for forming a porous network of a-CNF/PRA. SEM photographs and pore structure analysis indicated that a-CNF/C composite aerogel (a-CNF/CA) developed a stable porous skeletal structure during carbonization. TEM images revealed that the complete porous skeleton consisted of a-CNF encapsulated by carbon layers. The carbonization shrinkage of a-CNF/CA was only 26.53% due to the presence of a-CNF as the skeleton support. Compared to carbon aerogel, a-CNF/CA exhibited lower density (0.072 g cm−3), thermal conductivity (0.0452 W m−1 K−1), and higher compressive strength (up to 3.26 MPa) up to 3.26 MPa than that of carbon aerogel (1.21 MPa). These findings confirmed the excellent mechanical and thermal insulation properties of a-CNF/CA. [ABSTRACT FROM AUTHOR]

In the ultrasonic testing of the mechanical properties of ferromagnetic materials, the main excitation mechanism modes of ultrasonic waves are Lorentz force mechanism ultrasonic and magnetostriction mechanism ultrasonic. Lorentz force mechanism ultrasonic mainly detects the conductive characteristics of materials, while magnetostriction mechanism ultrasonic mainly detects the hysteresis characteristics of materials. However, conventional electromagnetic acoustic transducers (EMATs) cannot simultaneously characterise these two characteristics of ferromagnetic materials. In this study, we conclude from the finite element simulation that a quantitative lift-off distance (i.e. the distance between EMAT and the specimen) can change the main mechanism mode of the excited ultrasonic wave. Based on this conclusion, an electromagnet electromagnetic acoustic transducer with dual main excitation modes (DM-E-EMAT) is designed, which can realise the dual mode switching of the main Lorentz force mechanism and main magnetostriction mechanism by adding or removing hollow square gasket. The ultrasonic testing of ferromagnetic materials based on the two main mechanisms of DM-E-EMAT can simultaneously characterise the conductivity and magnetostriction properties of ferromagnetic materials, which enables the characterisations of two types of characteristic parameters with one transducer, improves the efficiency of electromagnetic ultrasonic non-destructive testing of the mechanical properties and reduces the detection errors of ferromagnetic material. [ABSTRACT FROM AUTHOR]

Microcapsules encapsulating payloads are one of the most promising delivery methods. The mechanical properties of microcapsules often determine their application scenarios. For example, microcapsules with low mechanical strength are more widely used in biomedical applications due to their superior biocompatibility, softness, and deformability. In contrast, microcapsules with high mechanical strength are often mixed into the matrix to enhance the material. Therefore, characterizing and regulating the mechanical properties of microcapsules is essential for their design optimization. This paper first outlines four methods for the mechanical characterization of microcapsules: nanoindentation technology, parallel plate compression technology, microcapillary technology, and deformation in flow. Subsequently, the mechanisms of regulating the mechanical properties of microcapsules and the progress of applying microcapsules with different degrees of softness and hardness in food, textile, and pharmaceutical formulations are discussed. These regulation mechanisms primarily include altering size and morphology, introducing sacrificial bonds, and construction of hybrid shells. Finally, we envision the future applications and research directions for microcapsules with tunable mechanical properties. [Display omitted] • Characterization methods of the mechanical properties of microcapsules are delineated. • Regulatory mechanisms of the mechanical properties of microcapsules are summarized. • The applications and future research directions of microcapsules with controllable mechanical properties are discussed. [ABSTRACT FROM AUTHOR]

Al2O3‐based composite seal with 10 wt% Al powder addition (A10) possesses excellent plastic and mechanical performance under wide temperature range of solid oxide fuel cell. The thickening phenomenon of A10 seal between 250°C–400°C and 600°C–750°C is caused by the thermal expansion of organic additives and the volume expansion when solid–liquid Al react with oxygen to form Al2O3. The thickness change rate reaches the maximum which is about 5% at 300°C and is about 4.46% at 650°C. The Gibbs free energy for reaction between Al and Al2O3 in the temperature range of 523–1 023 K is all less than 0, which is proved by the fact that A10 exhibits excellent self‐expansion and thermodynamic properties in the solid oxide fuel cell operating temperature. [ABSTRACT FROM AUTHOR]

A novel CaO–Al 2 O 3 –SiO 2 –Li 2 O (CASL) glass was developed for bonding yttria–stabilized zirconia ceramics (YSZ). The CASL glass possessed a coefficient of thermal expansion (CTE) that matched with YSZ and exhibited outstanding wettability on the surface of YSZ substrate. During the bonding process, mutual dissolution and diffusion between YSZ and CASL glass took place, which ensured good interface bonding. Furthermore, the rapid cooling speed led to a completely amorphous seam, which allowed the CTE of the seam to correspond with that of the original glass. The optimal flexural strength of YSZ/YSZ joints could reach more than 90 % of that of the YSZ. [ABSTRACT FROM AUTHOR]

Polymer-derived SiBCN ceramic aerogels have attracted extensive attention in recent years due to the excellent electromagnetic wave absorption and thermal insulation properties. With these merits, SiBCN aerogels are promising for the application of high-speed vehicles requiring thermal and electromagnetic shielding. However, the brittleness and poor mechanical property of SiBCN aerogel seriously hinder its practical applications. In this paper, SiBCN/SiBCN nf composite ceramic aerogels with enhanced mechanical property were prepared by combining electrospinning technique with simultaneous pyrolysis process of polyborosilane (PBS) fibers and precursor aerogels. The effect of varying fiber content on the density, mechanical property, thermal insulation as well as microwave absorption performance of the composite aerogel was investigated. In addition, the underlying toughness mechanism of the SiBCN/SiBCN nf composite ceramic aerogel was elucidated. The compressive strength of the SiBCN/SiBCN nf composite aerogel increased from 0.29 MPa to 1.62 MPa. Importantly, while the mechanical strength of the composite aerogel increased by about 5.5 times, SiBCN/SiBCN nf aerogel still exhibits low density of 0.105 g/cm³, low thermal conductivity of 0.048 W/mK and a minimum reflection loss (RL min) of −20 dB. Owing to the integration of electromagnetic wave (EMW) absorption and thermal insulation properties, SiBCN/SiBCN nf aerogels pave the way for the construction of thermal and electromagnetic shielding material for high-speed vehicles. [ABSTRACT FROM AUTHOR]

An enhanced Ni50A composite coating was formed on the AISI 1045 steel surface using Ti, B 4 C, and Ni50A powders. The work meticulously examined the effects of various process parameters, including laser power (800, 1200, and 1600 W) and scanning speed (4, 6, and 8 mm/s), as well as different Ti/B 4 C powder ratios (2:1, 3:1, and 4:1, mol.%) on the defect, hardness, wear resistance, and corrosion resistance of the coating. The microstructure of the coating showed that TiB 2 and TiC synthesized in situ were the key phases for coating enhancement, and there were a variety of solid solutions (FeNi 3 and Cr 2 Ni 3). TiB 2 particles showed dark gray hexagons and long rectangular blocks. The TiC particles mainly appeared in light gray dendritic shapes, occasionally petal-shaped and equiaxial forms, and grew around TiB 2. The research results showed that increased laser power and the Ti/B 4 C ratio decreased coating hardness and wear resistance. When the scanning speed increased, the hardness and wear resistance of the coating were significantly improved. The main wear mechanisms of the TiB 2 –TiC ceramic phase coating were oxidative wear and abrasive particle wear. Besides, the higher laser power and Ti/B 4 C ratio reduced the defect rate of the coating and enhanced the corrosion resistance. However, as the scanning speed increased, the defect rate increased, which decreased the corrosion resistance of the coating. The comprehensive performance evaluation showed that under the conditions of the laser power of 1200 W, a scanning speed of 8 mm/s, and a Ti/B 4 C ratio of 4:1, the coating exhibited optimal performance (dilution rate = 10.928 ± 0.090 %, defect rate = 8.657 ± 0.128 %, hardness = 63.300 ± 1.159 HRC, wear volume = 0.0149 ± 0.000100 mm3, Ecorr = − 0.565 ± 0.001 V, Icorr = 1.058 E − 06 ± 1.528 E − 09 A ⋅ c m 2). The results provide an important basis for research on the high-quality and efficient strengthening technology and performance of refractory alloys. [ABSTRACT FROM AUTHOR]

The scotch yoke inerter (SYI) is a new geometrically nonlinear vibration isolator with a smaller maximum transmissibility than linear inerter systems. The influence of internal friction and the damping effect on the response of the SYI system for seismic isolation can be significant and needs to be studied. In this study, a small-scale SYI is designed and tested, and an accurate model of SYI is developed for describing its dynamic behavior. Then, the motion equation of the coupled structure-SYI system is established, and several dynamic analyses are studied, including the amplitude-frequency response, the critical excitation amplitude, the backbone curve, the peak response, the starting frequency, and the linearization design, and many fitting expressions for engineering applications are proposed. Finally, the vibration isolation performance of SYI is investigated when friction and damping effects are considered or not, using a single-degree-of-freedom system and a building structure as examples. For harmonic excitations, the maximum transmissibility of the SYI system is superior to that of the linear inerter system, and its advantage becomes more obvious as the excitation amplitude increases. Its seismic isolation effect is slightly better than that of a linear inerter for seismic excitations, where the SYI considering friction and damping effects is better. Practical Applications: A scotch yoke inerter is a geometrically nonlinear inerter that is simple to construct, easy to implement, and has the advantage of variable inertance. The variation of inertance is reflected in two aspects: first, its nominal inertance can be changed by adjusting the location of the pin; second, its dynamic inertance is related to its deformation, which can provide greater negative stiffness effects for larger external excitations. The precise and simplified output force model of the scotch yoke inerter is provided, which can be applied to the calculation and verification of the output force in the design of scotch yoke inerters. Fitting expressions for the critical excitation amplitude, starting frequency, and linearization design are proposed, which can provide a theoretical basis for the application of scotch yoke inerters in base-isolated structures. Compared with traditional linear inerters, scotch yoke inerters have a better isolation control effect, and this control effect can be further improved by making reasonable use of the internal friction and the damping in SYI. [ABSTRACT FROM AUTHOR]

Expanded polystyrene (EPS) concrete is a new typical composite concrete, but its material toughness and hydrophilicity are poor, leading to low strength and poor toughness. To solve this critical issue, this study used an interactive method of experimentation and simulation to systematically study the mechanism of how the synergistic strengthening of styrene–butadiene latex (SBL) and polyvinyl alcohol (PVA) fibers improves the performance of EPS concrete from the macro, micro, and nano multiscale systems. Macromechanical tests showed that the mechanical properties of EPS concrete are obviously improved by adding PVA and SBL. PVA fiber can reduce the compressive strength of EPS concrete but increase the flexural strength. The addition of SBL has a positive effect on the anticompression and flexural properties. Observation and analysis of microexperiments using electron microscopy, X-ray diffraction, and infrared spectroscopy showed that the addition of SBL improved the weak interface zone, increased the hydration crystallinity of unhydrated cement products, and formed a more abundant cement-based gel to fill weak cement pores, resulting in a more uniform and stable internal structure. At nano scale, the molecular dynamics interface models of EPS/calcium silicate hydrate (C-S-H), EPS/SBL/C-S-H, PVA/C-S-H, and PVA/SBL/C-S-H were established and simulated and analyzed at the nanoscale. The results showed that the addition of SBL played a crucial role in connecting organic polymers with inorganic silicates in a "bridge" form. It formed numerous hydrogen bonds and ionic bonds with EPS, PVA molecular chains, and C-S-H, effectively stabilizing the crystalline layer structure of hydrated calcium silicate and compensating for the weak hydrophilicity of EPS particles, making the EPS/C-S-H and PVA/C-S-H systems more tightly stable. Practical Applications: Expanded polystyrene (EPS) foam concrete, with its advantages of ultralightweight, easy construction, and environmental friendliness, has been widely used in the construction industry. It finds applications in load-bearing precast concrete components, thermal insulation boards, cushioning or structural insulation boards, composite floors, pavement substrates, building envelope structures, and offshore floating structures, among others. These structures possess high strength, excellent insulation performance, high fire resistance, good water repellency, affordability, and strong sound absorption and noise reduction capabilities. However, the hydrophobic nature and porosity of EPS material result in uneven stratification and segregation during the preparation of EPS particles, as well as the existence of numerous weak interface transition zones between EPS and cement-based materials. In order to further expand its prospects in engineering applications and meet the requirements of modern engineering, it is necessary to enhance the workability and mechanical performance of EPS concrete. This study combines experiments and simulations to investigate the mechanisms and methods for reinforcing EPS concrete from a multiscale and multiangle perspective, providing references for the preparation of more stable and high-performance EPS concrete. [ABSTRACT FROM AUTHOR]

Quasi-static compression/tension, dynamic compression/shear mechanical property tests, fracture morphology characterization, dynamic response experiment, numerical simulation, and calculation of the ultimate penetration velocity of the high-strength steel under the impact of large mass low-velocity fragments and small mass high-velocity fragments were carried out to study the ballistic performance of high-strength steel used for armor vehicle protection and clarify its dynamic response under Ballistic impact. The fracture mode of the high-strength steel under dynamic impact compression and shear was shear failure. A large number of fine parabolic shear dimples were formed on the fracture surface. The high-strength steel had an obvious strain rate strengthening effect and adiabatic shear sensitivity. The plug formed under the low-velocity impact of a large mass fragment was a cone shape, and the impact area of the target plate underwent slight bending plastic deformation. The damage of the fragment to the target plate includes both adiabatic shear failure and ordinary shear failure. Under the high-velocity impact of small mass fragments, the fragments were seriously deformed and destroyed, and the damage model of the target plate is adiabatic shear failure. [ABSTRACT FROM AUTHOR]

Porous nickel-titanium (NiTi) manufactured using metal injection molding (MIM) has emerged as an innovative generation of drug-loaded stent materials. However, an increase in NiTi porosity may compromise its mechanical properties and cytocompatibility. This study aims to explore the potential of porous NiTi as a vascular drug delivery material and evaluate the impact of porosity on its drug loading and release, mechanical properties, and cytocompatibility. MIM, combined with the powder space-holder method, was used to fabricate porous NiTi alloys with three porosity levels. The mechanical properties of porous NiTi were assessed, as well as the surface cell growth capability. Furthermore, by loading rapamycin nanoparticles onto the surface and within the pores of porous NiTi, we evaluated the in vitro drug release behavior, inhibitory effect on cell proliferation, and inhibition of neointimal hyperplasia in vivo. The results demonstrated that an increase in porosity led to a decrease in the mechanical properties of porous NiTi, including hardness, tensile strength, and elastic modulus, and a decrease in the surface cell growth capability, affecting both cell proliferation and morphology. Concurrently, the loading capacity and release duration of rapamycin were extended with increasing porosity, resulting in enhanced inhibitory effects on cell proliferation in vitro and inhibition of neointimal hyperplasia in vivo. In conclusion, porous NiTi holds promise as a desirable vascular drug delivery material, but a balanced consideration of the influence of porosity on both mechanical properties and cytocompatibility is necessary to achieve an optimal balance among drug-loading and release performance, mechanical properties, and cytocompatibility. [ABSTRACT FROM AUTHOR]

Fiber-reinforced composites were widely used in aerospace, automotive, and wind energy industries, due to their lightweight, high specific strength and stiffness, design flexibility, and durability. This study prepared hybrid fiber preforms using a three-dimensional braided technique. These preforms made of carbon fiber (CF) and aramid fiber (AF) were reinforced into resin-based (ER) composites by a vacuum infusion process (VIP). Our study focused on evaluating the mechanical properties of these composites under different blend arrangements and ratios, with four blend arrangements including layer-by-layer, half-by-half, bundle-by-bundle, and block-by-block. The results showed that the bending strain of the composites with a 3:1 aramid fiber/carbon fiber yarn ratio (3AF1CF) increased by 105.56% compared to that of CF/ER, and the addition of AF improved the toughness of the composite. The tensile strength and modulus of the composites with a 3:1 carbon fiber/aramid fiber yarn ratio (1AF3CF) were improved by 31.17% and 109.68%, respectively, compared to those of AF/ER, and the bending strength and modulus increased by 106.12% and 115.32%, respectively, and increasing the CF ratio thus significantly improved the mechanical properties of the composites. In addition, in four hybrid arrangements with the same AF/CF ratio, the aramid fiber/carbon fiber yarn ratio of 2:2 (2AF2CF-4) possessed the best mechanical properties, with tensile strength and of 608.36 MPa and 13.8 GPa, and bending strength and modulus of 417.203 MPa and 22.9 GPa, respectively. [ABSTRACT FROM AUTHOR]

Red clay exhibits characteristics such as softening owing to water absorption and cracking because of water loss, which can lead to slope instability, road cracking, and compromised structural integrity when used directly in roadbed filling. Although the addition of industrial materials such as cement is a common engineering treatment, it severely impairs soil renewability. Lignosulfonate (LS) extracted from paper plant waste fluids is a natural bio-based polymer with promising applications as a soil improver. In this study, the boundary moisture content and mechanical properties of LS-treated red clay were investigated using Atterberg, unconfined compressive strength, and direct shear strength tests. Additionally, the LS-treated red clay modification mechanism was explored at multiple scales using zeta potential analysis, X-ray diffraction, scanning electron microscopy coupled with energy dispersive spectroscopy, and Fourier transform infrared spectroscopy. The results indicated that the LS dosage significantly affected both the water content and mechanical strength of the red clay boundaries. The optimal dosage of LS for red clay was 3 wt. %, at which the liquid limit was reduced by 32.97%, the plastic limit by 19.33%, and the plasticity index by 48.37%. The 28-day compressive strength of LS-treated red clay was increased by 378.4%, and the direct shear strength was increased by 136%. Analysis of the microstructure and mineral composition revealed that the LS-treated red clay did not form new minerals, but primarily filled pores and connected soil particles. Through the combined effects of hydrogen bonds, electrostatic interactions, and cation exchange, the LS-treated red clay reduced the size of the mineral particles and the thickness of the mineral double electric layer, resulting in increased structural densification. These results are of great scientific significance for the ecological modification of soils. [ABSTRACT FROM AUTHOR]

Lubricant‐infused organo‐gels with low surface energy solvents represent an environment‐friendly lubricating material, while the poor mechanical performance incapacitates them to harsh and intricate service conditions. To address this challenge, a simple yet highly effective strategy to prepare strong, smart, and slippery organo‐gels by glassifying the polymer network is reported. As a proof of concept, appropriate amounts of rigid solvophobic poly(phenyl methacrylate) (PPMA) units are integrated into a solvophilic poly(cyclohexyl acrylate) (PCHA) network infiltrated with lubricant. Upon forming bicontinuous phase‐separated structures, the rigid solvent‐free PPMA segments stay in glassy states, serving as a load‐bearing phase to toughen the materials effectively. Meanwhile, the soft PCHA phase maintains lubricity and extensibility by holding a substantial amount of lubricant. Owing to the synergistic effect, the gels manifest glass‐like mechanical performance with high rigidity (46.6 MPa), strength (7.7 MPa), and toughness (23.7 kJ m−2). Moreover, the materials exhibit high thermo‐sensitivity with the elastic modulus reversibly decreasing from 46.6 MPa at 20 °C to 0.23 MPa at 50 °C, endowing the gels with shape‐memory properties. Furthermore, the organo‐gels display satisfactory anti‐adhesiveness to various foreign matters. Taken together, the work represents a facile and universal strategy to reinforce organo‐gels, thereby adapting them to various applications. [ABSTRACT FROM AUTHOR]

Highlights With the rapid development of modern transportation systems, optimizing the relationship between structure and performance to obtain natural rubber‐based nanocomposites with excellent comprehensive performance is still worth to investigation. Herein, the regulation of flocculation potential through different flocculants selection on the thermomechanical properties for carbon black/graphene oxide reinforced natural rubber (CB/GO/NR) nanocomposites were investigated based on the compression electric double layer theory. The results showed that formic acid owned the highest zeta potential with comparison of sodium chloride (NaCl), calcium chloride (CaCl2), and aluminum chloride (AlCl3). Meanwhile, as the content was 8 wt%, tensile strength, tearing strength and thermal conductivity could achieve to 27.64 MPa, 56.89 N/mm, and 1.05 W m−1 K−1, respectively. While the heat generation after compression fatigue dropped to 10.1°C. These findings reveal that the highest zeta potential of formic acid could promote the improvement of flocculation degree between GO and NR latex and significantly enhanced the thermomechanical properties of CB/GO/NR nanocomposites due to the larger flocculation potential difference. Therefore, this study not only provides important theoretical insights for preparing high‐performance NR‐based nanocomposites, but also highlights the crucial role of high zeta potential flocculants in optimizing the composite performance. More importantly, the findings offer the creative insights for preparation of the excellent comprehensive NR nanocomposites for the practical industry application. The effect of flocculation degree on the properties of CB/GO/NR composites was studied. Formic acid was benefit to the flocculation and could promote the surface interaction. CB/GO/NR composites possessed the improved thermal and mechanical properties. [ABSTRACT FROM AUTHOR]

For the reaction-formed graphite/SiC composites, the presence of cracks and poor mechanical properties seriously affect their reliability as wear resistant or sealing materials. In this work, a porous carbon preform was pressure formed first by carbon-composite-powder (PFC@G) and carbon black, impregnated with resin and carbonized subsequently, which can heal the micro-cracks, increased the strength of porous carbon preforms and finally reduce the reactivity of liquid Si and carbon during the reaction forming process. The results show that the modified porous carbon preform has a 4.8 % reduction in porosity and a 3.98 times increase in compressive strength. After reactive melt infiltration, the prepared graphite/SiC composites had a compact and isotropic structure and obtained the highest carbon content of 66.18 vol%. In addition, the coupling effect of the PFC@G size on the carbon content and mechanical properties of composites was studied. With the decreasing of the PFC@G size, the mechanical properties of the composites increased and the carbon content decreased. The sample with a carbon content of 48 vol% and a bending strength of 137 MPa exhibited excellent self-lubrication properties. [ABSTRACT FROM AUTHOR]

Thermal shock resistance and mechanical reliability of aluminum nitride (AlN) ceramic substrates are essential in electronic device modules. In this study, the thermal shock behavior of AlN doped with aluminum - yttrium oxide (Al - Y 2 O 3) was explored. The results indicate that adding Al to AlN ceramics increases its flexural strength, thermal conductivity, and thermal expansion coefficient. The microcracks caused by thermal mismatch between the AlN matrix and the secondary phases relieved internal stress, thereby improving thermal shock resistance of AlN ceramics. Furthermore, the addition of Al isolates and homogenizes the secondary phases, resulting in a more uniform microstructure and strengthened grain boundaries, which enhance the flexural strength, Weibull modulus, and thermal shock resistance. After introducing 0.5 wt% Al, the Weibull modulus of AlN ceramics increased by 73.37 %, and their critical thermal shock temperature difference exceeded 800 °C, with a maximum residual strength of 488.01 ± 48.26 MPa at 600 °C. Overall, an appropriate amount of Al improves the reliability and thermal shock resistance of AlN ceramics. [ABSTRACT FROM AUTHOR]

Based on the advantages of triply periodic minimal surface (TPMS) porous structures, extensive research on NiTi shape memory alloy TPMS scaffolds has been conducted. However, the current reports about TPMS porous structures highly rely on the implicit equation, which limited the design flexibility. In this work, novel shell-based TPMS structures were designed and fabricated by laser powder bed fusion. The comparisons of manufacturability, mechanical properties, and shape recovery responses between traditional solid-based and novel shell-based TPMS structures were evaluated. Results indicated that the shell-based TPMS porous structures possessed larger Young's moduli and higher compressive strengths. Specifically, Diamond shell structure possessed the highest Young's moduli of 605.8±24.5 MPa, while Gyroid shell structure possessed the highest compressive strength of 43.90±3.32 MPa. In addition, because of the larger specific surface area, higher critical stress to induce martensite transformation, and lower austenite finish temperature, the Diamond shell porous structure exhibited much higher shape recovery performance (only 0.1% residual strain left at pre-strains of 6%) than other porous structures. These results substantially uncover the effects of structural topology on the mechanical properties and shape recovery responses of NiTi shape memory alloy scaffolds, and confirm the effectiveness of this novel structural design method. This research can provide guidance for the structural design application of NiTi porous scaffolds in bone implants. [ABSTRACT FROM AUTHOR]

Copyright of China Plastics / Zhongguo Suliao is the property of Journal Office of CHINA PLASTICS 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.)

Copyright of China Plastics / Zhongguo Suliao is the property of Journal Office of CHINA PLASTICS 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.)

Carbon fiber reinforced polyamide 66 (CF/PA66) sheets are ultrasonically welded by applying nylon meshes as energy directors (EDs) in this paper. The influence of mesh dimensions is revealed by observing the joint formation process, joint mechanical performance, joint cross‐sectional morphology and joint failure mode. Results show that the joint formation process can be divided into wire flattening stage, ED spread stage, tight bonding stage, and mixing stage. The nylon mesh ED with moderate wire spacing, small wire diameter and small mesh area promotes better weld quality. Welding energy will be dispersed rather than concentrated if the mesh area is too large, resulting in reduced failure load. The joints exhibit two fracture modes: interfacial fracture (IF) and workpiece fracture (WF), and the fracture mode of the joints with nylon mesh EDs transits from IF to WF as the welding energy increases. Highlights: Five types of nylon mesh are used as energy directors to join CF/PA66 sheets by ultrasonic welding.The influence of nylon mesh dimensions on the mechanical property and fracture mode of joints is investigated.The formation process of ultrasonically welded joints can be separated into wires flattening stage, ED spread stage, tight bonding stage, and mixing stage. [ABSTRACT FROM AUTHOR]

As is well known, Laser print paper is usually produced with high‐quality chemical wood pulp. The laser print waste paper fiber (LPWF) is a high‐quality secondary fiber, and the research and development of high‐value utilization technology for laser print waste paper has attracted much attention in the field of renewable resource recycling. In this study, LPWF was used to reinforce poly(lactic acid) (PLA) composites in the field, and the composites were modified with bioenzyme, cationic polyacrylamide (CPAM), and nano‐silicon carbide (Nano‐SiC) to enhance the interfacial compatibility of LPWF/PLA composites. The study systematically investigated the effects of various modification methods on the characteristics and degradability of composites made from laser print waste paper fiber reinforced PLA resin matrix. The results showed that the mechanical properties of the composites treated with CPAM and Nano‐SiC were significantly improved, with tensile strengths of 54.3 and 59.5 MPa, and flexural strengths of 85.1 and 91.5 MPa, respectively, and the water absorption of the composites was reduced after the modification treatment, while the thermal stability was improved. The degradation performance of the composites in various water environments indicated that the inclusion of LPWF accelerated the water degradation rate of the composites, with the maximum degradation rate of the composite reaching 1.26% in 30 days. Highlights: Laser print waste paper is an excellent quality recyclable fiber resource.Four modifiers were used to modify LPWF/PLA composites.Characteristics and degradability of the composites were investigated.Significantly improved properties of CPAM and Nano‐SiC modified composites.The degradation rate of composites is increased by the addition of LPWF. [ABSTRACT FROM AUTHOR]

Additive Manufacturing (AM) of carbon fiber reinforced polyetheretherketone (CF/PEEK) composites with excellent performance by Powder Bed Fusion (PBF) has great potential in the applications where high strength and high service temperature are required. However, the reinforcement mechanisms of CF/PEEK composites based on the PBF process are complex and show significant differences from traditional processing methods. In this paper, the mechanical properties of CF/PEEK prepared by PBF were investigated. The results showed that its X‐axis tensile strength and modulus were approximately equal to or a bit lower than the theoretical value with randomly distributed CF, but much lower than the theoretical value with unidirectional distribution of CF in composites. Meanwhile, mechanical strength anisotropy was observed. The composites' Y‐axis tensile strength was slightly lower than X‐axis, and the lowest strength existed in Z‐axis. To improve the weak Z‐axis strength, post‐processing of annealing and solvent‐induced crystallization were carried out, and the Z‐axis tensile strength of post‐processed parts reached 50 MPa, which was 62% higher than untreated samples. Consequently, suitable CF and proper post‐ processing for AM of high strength CF/PEEK were proposed, which would promote the industrial application of this technology. Highlights: The effect of CF on mechanical property of CF/PEEK prepared by PBF were studied.The optimal CF for PBF of high strength CF/PEEK were obtained.The post‐processing method for improving the Z‐axis strength were proposed.CF/PEEK with comprehensive mechanical property was successfully prepared by PBF. [ABSTRACT FROM AUTHOR]

Highlights Recently, thermosetting epoxy resin is expected to be substituted by thermoplastic featured from green circular economy. Poly(methyl methacrylate) (PMMA) has been well known as one promising thermoplastic resin, although its mechanical property needs to be further investigated. In this paper, the free radical polymerization of methyl methacrylate (MMA) was initiated by lauroyl peroxide/N,N‐dimethylaniline (LPO/DMA) and lauroyl peroxide/N,N‐dimethyl‐p‐toluidine (LPO/DMT) redox system at room temperature, respectively. The PMMA (n(MMA:LPO:DMA) = 200:1.2:1) exhibited excellent mechanical properties, and the tensile strength was 66.5 MPa, the bending strength was 118.0 MPa. The tensile strength increased to 78.9 MPa at −40°C, which suggested a promising application at low temperature. The resin was applied to fabricate continuous glass fiber reinforced PMMA (GF/PMMA) composites by vacuum‐assisted resin infusion. The 0° tensile strength and modulus were 1.17 and 43.7 GPa and 90° tensile strength and modulus were 48.3 MPa and 13.2 GPa, respectively. The mechanical properties of GF/PMMA composites are higher than GF/epoxy. Moreover, PMMA resin and glass fiber can be recycled from GF/PMMA composites by MMA as solvent, which is more energy‐efficient and environment‐friendly. This work is of great significance for preparing sustainable resin and composites. GF/PMMA composites were fabricated by vacuum perfusion. GF/PMMA composites showed higher mechanical properties than GF/epoxy. GF/PMMA composite was recycled with MMA and closed‐loop recovery was achieved. [ABSTRACT FROM AUTHOR]

BACKGROUND: In recent years, additive manufacturing (also known as 3D printing) has gradually become the mainstream method for producing titanium alloy brackets for removable partial dentures. Heat treatment, as an important method to improve the mechanical properties of 3D printed titanium alloys, has become a current hot topic of attention. OBJECTIVE: To summarize the main heat treatment technologies currently applied to 3D printed titanium alloy specimens (including annealing, solution aging, hot isostatic pressing, and other heat treatments) and their effects on the mechanical properties and microstructure of 3D printed titanium alloy specimens, providing a theoretical basis for improving the heat treatment technology of removable partial denture titanium alloy supports. METHODS: A computer search was conducted on research materials related to 3D printed titanium alloy heat treatment in databases such as CNKI, PubMed, and ScienceDirect. The search period was from 2012 to 2023. A total of 61 articles were selected based on inclusion and exclusion criteria. RESULTS AND CONCLUSION: (1) Using conventional annealing techniques to treat 3D printed titanium alloy specimens, keeping them at 500-900 °C for 2-4 hours, can effectively increase the elongation of 3D printed titanium alloy specimens. (2) Compared to conventional annealing techniques, solid solution aging treatment is more complex, and the titanium alloy specimens after solid solution aging treatment exhibit outstanding yield strength and better corrosion resistance. However, the 3D printed titanium alloy specimens after solid solution aging treatment have no advantage in terms of ductility. (3) Hot isostatic pressing treatment can reduce the internal defects of 3D printed titanium alloy specimens, significantly increase the elongation of 3D printed titanium alloy specimens, and increase their fatigue life. (4) Rapid heat treatment can significantly improve the elongation of 3D printed titanium alloy specimens, and the speed is faster. In terms of elongation improvement and heat treatment efficiency, it has more advantages than conventional annealing in the past. (5) The improvement of elongation of 3D printed titanium alloy specimens by cyclic heat treatment exceeds that of conventional annealing. Cyclic heat treatment can significantly improve the grain structure of 3D printed titanium alloy specimens, but the heat treatment time is too long and the efficiency is low. [ABSTRACT FROM AUTHOR]

The dispersion of silica in rubber systems and its interaction with rubber are two key factors in the preparation of rubber composites with excellent properties. In view of this, silica modified with terminal isocyanate-based polybutadiene liquid rubber (ITPB) is used to improve the dispersion effect of silica in rubber and enhance its interaction with the rubber matrix to improve the rubber's performance. The impact of different modification conditions on the dispersion of silica and the properties of modified silica-filled rubber composites were studied by changing the amount of ITPB and the modification method of silica, including blending and chemical grafting. The experimental results show that ITPB is successfully grafted onto silica, and the use of modified silica improves the cross-linking density of rubber, promotes the rate of rubber vulcanization, and overcomes the shortcomings of the delayed vulcanization of silica itself. When the ratio of ITPB liquid rubber to silica equals 1:20, the comprehensive performance of rubber is the best, the ITPB-modified silica has a better dispersion effect in rubber, and the rolling resistance is slightly improved, with tensile strength reaching 12.6 MPa. The material demonstrates excellent overall performance and holds promise for applications in the rail, automotive, and electrical fields. [ABSTRACT FROM AUTHOR]

Cu alloys have been widely used in the manufacture of liners because of their high density, good plasticity, and excellent thermal conductivity. In order to achieve excellent jet stability and penetration performance, it is necessary to further improve the mechanical properties of Cu-based liners. Nevertheless, the simultaneous enhancement of strength and ductility of the Cu alloys remains a huge challenge due to the strength–ductility trade-off phenomenon of metals/alloys. In this study, the microstructure evolution of rare earth Nd-modified Cu alloy and its effect on mechanical properties were investigated using OM, SEM, EBSD, and TEM techniques. The results show that the ultimate tensile strength (218 MPa) and elongation (50.7%) of sample 1 without Nd are the lowest. With increasing Nd content; the tensile strength and elongation of the samples increase; and the mechanical properties of sample 4 are the best, with a tensile strength of 278.6 MPa and elongation of 65.2%. In addition, with the increase in Nd content, not only is the grain size of the Cu-Nd alloy refined, but also the strength and plasticity are improved so that the strength–ductility trade-off phenomenon is improved. The strength improvement is mainly attributed to grain refinement strengthening, dispersion strengthening, and strain hardening. The increase in ductility is mainly related to the improvement of the microstructure heterogeneity by the Nd element. [ABSTRACT FROM AUTHOR]

To investigate the mechanical properties and microstructure evolution of P92 steel during long-term service, the operated P92 main steam pipes from the first ultra-supercritical units in China were sectioned into samples representing various service durations and stresses (0# (as-received state, 1# (82,000 h, 67.3 MPa), 2# (85,000 h, 78.0 MPa), and 3# (100,000 h, 80.3 MPa)). Thereafter, a comprehensive assessment of their mechanical properties, including tensile strength, impact, hardness, and creep resistance, as well as a detailed microstructure analysis, was carried out. The effect of stress on the aging of material properties during operation is discussed. The results show that the circumferential stress caused by the increase in the internal steam pressure can significantly promote the creep life consumption of P92 steel, resulting in the degradation of mechanical properties and the expedited aging of the microstructure. The Rp0.2 and Rm of the P92 main steam pipe at room temperature and 605 °C decreased with the service time increase, reflecting the influence of stress in operation, which is expected to be used for the residual life evaluation of P92 steel. The relationship between the impact absorption energy (FATT50), Brinell hardness, and the operating time of P92 operating pipes is non-monotonic, indicating that these parameters are not sensitive indicators of material aging due to stress. The evaluation of performance degradation in P92 operating pipes due to stress-induced aging is not reliably discernible through optical metallography alone. To achieve a thorough assessment, the use of transmission electron microscopy (TEM) is essential. [ABSTRACT FROM AUTHOR]

Wire rope isolator (WRI) devices are widely used in vibration reduction industrial equipment, and stiffness is the key parameter that determines isolation effectiveness. WRI devices show slight nonlinearity under small loads, and the manufacturers generally only provide the initial parameters. To investigate the mechanical behavior changes in the WRI devices under repeated loads, five types of WRI specimens were tested under various amplitudes, loading speeds, and preloads. The test results of large symmetrical compression and tension loads showed that the WRI devices demonstrated stable hysteresis curves under repeated loads, while the hysteresis curves were independent of the loading speed. The test results of small cyclic loads with large preloads show that the stiffness of the WRI specimen follows the logarithmic law, with the cycle number under various loading conditions. Particularly, the stiffness of the specimen increases by about 10–30% after 50 cycles. The initial stiffness Ka decreases linearly with the preloads, while the decrease is quadratic in relation to the cyclic load. The hardening coefficient Ca shows a positive correlation with the loading capacity of the WRI devices, while it shows a negative correlation with the preload and cyclic load amplitudes. It is recommended to consider the stiffness increase in the WRI devices during the evaluation of isolation effectiveness. [ABSTRACT FROM AUTHOR]

[Display omitted] Enhancing the flame retardancy of epoxy (EP) resins typically entailed a trade-off with other physical properties. Herein, hyperbranched poly(amidoamine) (HPAA) and phytic acid (PA) were used to functionalize graphene oxide (GO) via electrostatic self-assembly in water to prepare a phosphorus-nitrogen functionalized graphene oxide nanosheet (PN-GOs), which could be utilized as high efficient flame-retardant additive of epoxy resin without sacrificing other properties. The PN-GOs demonstrated improved dispersion and compatibility within the EP matrix, which resulted in significant concurrent enhancements in both the mechanical performance and flame-retardant properties of the PN-GOs/EP nanocomposites over virgin EP. Notably, the incorporation of just 1.0 wt% PN-GOs yielded a 20.4, 6.4 and 42.7 % increases in flexural strength, flexural modulus and impact strength for the PN-GOs/EP nanocomposites, respectively. Furthermore, simultaneous reductions were achieved in the peak heat release rate (pHRR) by 60.0 %, total smoke production (TSP) by 43.0 %, peak CO production rate (pCOP) by 57.9 %, and peak CO 2 production rate (pCO 2 P) by 63.9 %. This study presented a facile method for the design of GO-based nano flame retardants, expanding their application potential in polymer-matrix composites. [ABSTRACT FROM AUTHOR]

In this paper, we propose an effective method for doping WC into Ta-Hf-C ceramics to significantly enhance their densification and mechanical properties. An increasing WC doping amount from 0 to 20 at.%, enhances the densification of Ta-Hf-C ceramics from 92.4 % to 99.1 %. This is mainly due to the fact that the doping of WC effectively removes the harmful oxygen impurities from the ceramics, thereby increasing their sintering activity. Furthermore, the doping of WC plays an active role in the mechanical properties of the ceramics. The Ta-Hf-C doped with 15 at.% WC has the highest value of 36.41 GPa for nano-hardness due to the solid solution strengthening mechanism, while the highest Vickers hardness (38.75 GPa) and fracture toughness (3.76 MPa m1/2) appear in Ta-Hf-C doped with 20 at.% WC. The main toughness mechanism is W segregation at the grain boundary, enhancing grain boundary strength. [ABSTRACT FROM AUTHOR]

The introduction of pores to improve the toughness of alumina ceramics is considered to be a feasible strategy by using the inhibitory effect of pores on crack propagation. However, the mechanical properties of alumina ceramics are often reduced due to the uncontrollable pore shape. In this work, the nano-scale C@Al 2 O 3 core-shell particles were fabricated and introduced into the alumina powder treated by dielectric barrier discharge plasma-assisted milling, and the alumina ceramics with closed pores of regular shape (approximate sphere) and small size (<1 μm) were prepared. Since the approximate spherical pore structure and small pore size eliminate the adverse effects of stress concentration, and the deflection and pinning effect of closed pores on cracks, the flexural strength and fracture toughness of the prepared samples were improved, increasing by 12.6 % and 18.8 % respectively. [ABSTRACT FROM AUTHOR]

An essential tool for assessing the viscoelastic characteristics and temperature transitions of polymer composites is dynamic mechanical analysis (DMA). This research looked at the influence of process factors on the flexural and DMA properties of the coir fiber composite. These variables were fiber laying, length of the fiber, fiber volume percentage, and fiber surface treatment with alkali. According to Taguchi L18 design, needle-punched nonwoven was developed. Through this investigation, the optimized flexural strength of the sample was found as 52.812 MPa. According to DMA research, the greatest storage modulus, loss modulus, and loss factor were found to be 3.24 GPa, 0.508 GPa, and 0.164 Gpa at 26 °C and 55% RH. The best outcomes were obtained using cross-directional fiber laying, 6-cm fiber length, 40% fiber volume fraction, and 3% sodium hydroxide pretreatment. It was discovered by statistical analysis that the alkali pretreatment parameter had a significant relationship with both the flexural and dynamic mechanical characteristics of the composite. [ABSTRACT FROM AUTHOR]

Basalt fibers, known as "green materials without pollution in the 21st century", have gained widespread attention due to its good mechanical properties. Basalt fiber‐based composites have applications in various fields such as construction, transportation, energy, and protection. However, as an inorganic fiber material, basalt fiber is hard and brittle and prone to catastrophic failure, reducing the safety of the material. Therefore, it is important to strengthen the toughness of basalt fiber‐based composites. This paper reviews the contributions made by researchers in recent years to enhance the toughness of basalt fiber reinforced composites. It mainly focuses on four aspects: physical and chemical modification of fibers surface, mixed application of multiple fibers, different textile and 3D printing technology, and design of biomimetic structures. Through these methods, the toughness of basalt fiber‐reinforced composite materials was increased by 10%–90%. In today's advocacy for green industrial development, the research and application of basalt fibers are very important for advancing the process of green development. These contributions can promote the application of basalt fiber in engineering fields. Highlights: Basalt fiber is a green material without pollution.Basalt fiber reinforced composites is the key material for engineering field.Strengthening interfacial adhesion can significantly improve the toughness of composites.Basalt fibers can serve as an alternative to glass fibers in composite materials.The hybridization of basalt fibers with soft fibers can effectively enhance the toughness of composites. [ABSTRACT FROM AUTHOR]

Continuous carbon fiber‐reinforced poly(ether‐ether‐ketone) composites (CCF/PEEK) are widely used in aerospace. However, long‐term service to elevated temperatures induces material aging in CCF/PEEK composite structures, significantly reducing their load‐bearing capacity. In this paper, the mechanisms of thermal aging effects on the mechanical properties of CCF/PEEK composites were investigated. Mechanical performance experiments were conducted on three‐point bending, short beam shear, and double cantilever beam specimens after accelerated aging in the range of 250–300°C. The evolution mechanism of crystallization behavior and aging characteristics was revealed through differential scanning calorimetry and thermogravimetric analysis. The results indicated that thermal aging primarily impacted the mechanical properties of CCF/PEEK composites through changes in crystallization and interfacial properties, which were highly sensitive to aging temperature, particularly with crystallization exhibiting temperature−/time‐ dependent behaviors during aging. The thermal aging environment promoted the growth and perfection of the crystals. However, at higher temperatures, further aging caused cross‐linking and degradation, resulting in a significant decrease in crystallinity following an initial increase. Moreover, the rate of oxidation and decomposition of the sizing agent escalated with increasing aging temperature, which led to a significant decline in interfacial properties. Generally, thermal aging at 250°C contributed to the improvement of bending and interlaminar shear properties of the composites. However, at 300°C, a significant decrease in both bending and interlaminar shear properties, as well as mode‐I interlaminar fracture toughness. Highlights: The effect and mechanism of thermal aging on the mechanical properties of continuous carbon fiber‐reinforced poly(ether‐ether‐ketone) composites are investigated within the temperature range of 250–300°C.Thermal aging significantly influences the mechanical properties of the composites primarily by inducing alterations in both crystallization and interfacial properties.The differential scanning calorimetry (DSC) experimental results reveal that the crystallization of the PEEK matrix exhibits temperature−/time‐ dependent behaviors during thermal aging.Further aging at 300°C induces oxidation and decomposition of components such as sizing agents, resulting in interfacial debonding.The experimental results indicate that aging at 250°C is conducive to improving the mechanical properties and thermal stability of the composites. [ABSTRACT FROM AUTHOR]

Inorganic fillers like hexagonal boron nitride (h‐BN) have the potential to enhance the thermal conductivity of polymer mixtures. However, it has been restricted due to poor dispersion of particles in polymer matrices by melt mixing process. The addition of inorganic powders into sticky prepolymer is expected to alleviate the aggregation of powders. In this paper, h‐BN/polymethyl methacrylate (PMMA) composites were prepared by in situ polymerization of methyl methacrylate (MMA) with 5 and 20 μm of h‐BN particle as fillers respectively, for even distribution of fillers with in composites. The structures and properties of composites were characterized by FT‐IR, DSC, TGA, SEM, laser thermal conductivity meter and universal electronic tester. By SEM, it can be seen that a highly uniform dispersion of h‐BN in PMMA. When the mass fraction of h‐BN is 20 wt%, the thermal conductivity of the composites is increased by 107% for 5 μm h‐BN and 189% for 20 μm h‐BN, respectively. With the mass constituting of 5 wt% h‐BN, majority of mechanical characteristics of the composite, such as tensile strength, tensile modulus, along with impact strength, are enhanced, alongside a decrease in bending strength. This work would provide a filling strategy of h‐BN into the polymer matrices to achieve uniform dispersion, and enhance both the thermoconductivity and mechanical strength of thermoplastic composites. Highlights: A technique for creating h‐BN/PMMA composites using in suit redox polymerization.Ehancing the thermal conductivity of these composites is achievable through the even distribution of h‐BN flakes within the PMMA matrix.It provides a reference for the design of future h‐BN/PMMA composites with favorable the thermal conductivity which achieves a good balance between performance and cost. [ABSTRACT FROM AUTHOR]

Poly(N‐isopropylacrylamide) (PNIPAM) gels change their volume and hydrophilicity in response to temperature stimulus in flexible actuators, flexible sensors, and energy storage management. However, traditional PNIPAM gels exhibit low mechanical properties and poor self‐recovery ability due to weak intermolecular (chain) interactions and necessary covalent crosslinking. Herein, a water/ionic liquid (H2O/IL) binary solvent system that provides additional hydrogen bonding and hydrophobic interactions as well as can significantly increase the solubility (up to 60 wt.%) of NIPAM is developed. The fully physically crosslinked PNIPAM ionogel is prepared by utilizing the H2O/IL binary solvent and exhibited excellent mechanical performances, rapid self‐recovery properties, and strong adhesion strength. In addition, the lower critical solution temperature of the PNIPAM ionogel can also be tuned over a wide range (37‐70 °C) by adjusting the IL ratio in the binary solvent. Furthermore, based on the temperature sensitivity and ionic conductivity of the PNIPAM ionogel, applications of PNIPAM ionogels in smart devices, temperature‐managed adhesion, and flexible sensing are demonstrated, respectively. This work improves various performances of PNIPAM gels by using the H2O/IL binary solvent to adjust non‐covalent interactions and provided new ideas for developing high‐performance temperature‐sensitive gels. [ABSTRACT FROM AUTHOR]

Highlights The 3D woven spacer fabric lightweight composites (WSFC) show promising applications in construction, transportation and aerospace. In this study, the 3D WSFC with different structural variations (e.g., layer thicknesses, stacking and face layer thickening) were designed and fabricated. The fracture strengths of single‐layer WSFC in the weft direction with layer thicknesses of 5, 10 and 15 mm were 54.4, 14.3, and 5.4 MPa. In the weft direction, the fracture strengths of double‐ and triple‐stacked 3D WSFCs were 30.6 and 21.7 MPa, which improved 1.1 times and 3.0 times as compared with those of original single‐layer 3D WSFCs, respectively. The double‐ and triple‐stacked WSFC also had large flexural deformation. The 3D WSFC with double‐layer misaligned stacking had the similar flexural strengths in both directions, which obviously reduced the performance differentiation of 3D WSFC in different directions. With the addition of face layer fabric, the mechanical performances of 3D WSFC were notably enhanced, and the damage modes were changed from brittle failure to ductile failure. Furthermore, a multi‐scale model of 3D WSFC with different structural variations was developed for numerical simulation to analyze the stress distribution and damage mechanism. Stacking design obviously improves mechanical properties of 3D WSFC. WSFC with misaligned stacking has similar flexural strengths. A multi‐scale elastic–plastic damage model for 3D WSFC is established. Damage modes of WSFC are changed with the stacking method. [ABSTRACT FROM AUTHOR]

Microextrusion‐based additive manufacturing of zirconia‐based bioceramics is capable of fabricating design‐specific architectures with high mechanical strength properties and relative density. We developed a novel organic residue‐free binder system for zirconia paste printing (ZP2) with the shear‐thinning properties apropos to microextrusion‐based 3D printing. Based on thermogravimetric analysis, debinding protocol was established followed by high‐temperature heat treatment under four sintering conditions. Quantitative linear shrinkage (32.3%–42.7% ranging from in‐plane to vertical direction), density (83.3%–87.5%), and surface roughness (7.7–13.8 µm from the parallel to the perpendicular to the infill direction) as a factor of sintering conditions (1400°C–1500°C for 3–4 h) were analyzed. Whereas qualitative phase assemblage demonstrated “sintering condition independent” phase stability; grain growth and reduction in porosity were observed in the microstructure with increment in sintering temperature and hold time. Interestingly, at higher temperature and hold time, the compressive (46–72.4 MPa) and tensile strength (16.2–23.1 MPa) properties experienced a trade‐off between grain growth and reduction in porosity. The ZP2 scaffolds sintered at lower temperature and hold time qualified for the bone scaffold applications having interconnected porosities, biologically relevant surface roughness, and human bone mimicking mechanical properties. With a unique finite element analysis recipe, the mechanical behavior of the “life‐like” reconstructed computer aided design (CAD) geometries identical to real 3D‐printed‐sintered ZP2 scaffolds was quantitatively predicted. [ABSTRACT FROM AUTHOR]

A 12-mm caliber gas gun was used to launch a high-strength steel cylindrical projectile to impact a polyurea-coated B4C ceramic target plate to investigate the effects of the polyurea coating position and the thickness of the polyurea coating on the protective ability of the ceramic composite target plate, reveal the penetration resistance mechanism of the polyurea-coated B4C ceramic plate and protection mechanism of polyurea coating. The result showed that the ceramic cone top diameter of the composite target plate coated with polyurea on the front side was 52.4–60.5% lower than that of the uncoated ceramic target plate, and the ceramic cone bottom diameter was 0.2–4% lower than that of the uncoated ceramic target plate. For the same area density, the ceramic target plate coated with polyurea on both sides had the largest percentage of mass remaining and the smallest mass of dislodged ceramic fragments. In addition, composite target plates coated with polyurea on the back side and both sides significantly reduced the head velocity of the post-target debris cloud. The polyurea coating on the front of the target plate utilizes the strain rate effect to dissipate the kinetic energy of the projectile and inhibit the spallation of ceramic fragments toward the front of the target plate. The polyurea coating on the back of the target plate utilizes bulge deformation to dissipate the kinetic energy of the projectile and intercepts the scattering of the post-target debris cloud. The polyurea coating effectively reduces ceramic target plate damage and improves composite target plate integrity level and resistance penetration. [ABSTRACT FROM AUTHOR]

The microstructure and mechanical properties of steel corrosion products in marine environment are key parameters for developing the concrete corrosioninduced model. In this study, steel corrosion products from steel plates, concrete specimens with 10 mm and 20 mm covers, and cracked beams in Zhejiang province were sampled and analyzed. Initially, the microstructure of the steel corrosion products were determined by X-ray diffractometry (XRD), thermogravimetric analysis (TG), scanning electron microscopy (SEM), and energy-dispersive spectrometry (EDS). Subsequently, the mechanical properties of steel corrosion products including nanoindentation elastic modulus, hardness and instantaneous elastic modulus were measured by nanoindentation and consolidation experiments. This study holds potential for establishing the concrete corrosion-induced model and assessment of the concrete structure durability in marine environment. [ABSTRACT FROM AUTHOR]

An attempt has been made to optimize areal density and number of layers of needle-punched jute nonwoven fabric for the development of a rigid composite with desirable performance properties using Taguchi L9 experimental design. The hand lay-up followed by compression molding protocol was used to prepare composite sheet with jute nonwoven fabric as reinforcement and unsaturated polyester resin as matrix. We evaluated the tensile strength, flexural strength, and volume of reinforcement of the developed composites, and analyzed the data in Minitab 18.0 software to optimize the processing conditions. Results inferred that the areal density of jute fabric reinforcement positively influenced the mechanical properties of the composite sheet, while the number of layers had a negative impact. Statistical analysis revealed that 400 GSM jute nonwoven fabric in three layers could be an optimum condition to develop a rigid composite sheet with the desirable properties of an automobile product. [ABSTRACT FROM AUTHOR]

Beetle femur–tibial joints can bear large loads, and the joint structure plays a crucial role. Differences in living habits will lead to differences in femur–tibial joint structure, resulting in different mechanical properties. Here, we determined the structural characteristics of the femur–tibial joints of three species of beetles with different living habits. The tibia of Scarabaeidae Protaetia brevitarsis and Cetoniidae Torynorrhina fulvopilosa slide through cashew-shaped bumps on both sides of the femur in a guide rail consisting of a ring and a cone bump. The femur–tibial joint of Buprestidae Chrysodema radians is composed of a conical convex tibia and a circular concave femur. A bionic structure design was developed out based on the characteristics of the structure of the femur–tibial joints. Differences in the failure of different joint models were obtained through experiments and finite element analysis. The experimental results show that although the spherical connection model can bear low loads, it can maintain partial integrity of the structure and avoid complete failure. The cuboid connection model shows a higher load-bearing capacity, but its failure mode is irreversible deformation. As key parts of rotatable mechanisms, the bionic models have the potential for wide application in the high-load engineering field. [ABSTRACT FROM AUTHOR]

The uniformity of growth and mechanical properties of grafted seedlings affect the quality of mechanical grafting operations. The growth uniformity of grafted seedlings in a greenhouse will be poor due to the uneven and unstable light and temperature conditions. Plant factories can cultivate grafted seedlings in the most suitable environment by regulating environmental parameters such as light and temperature. The aim of this study was to investigate the impact of the light conditions on tomato seedlings in plant factory and to develop an optimal cultivation light formula. The effects of light intensity (50, 100, 150, 200, and 250 μmol m−2 s−2) and photoperiod (10, 12, 14, 16, and 18 h a day(h/d)) on the morphological and mechanical properties of tomato seedlings were experimentally investigated. Orthogonal experiments were conducted involving light quality (R:B = 75:25, R:B = 50:50, and R:B = 25:75), light intensity (150 μmol m−2 s−2, 200 μmol m−2 s−2, and 250 μmol m−2 s−2), and photoperiod (14, 16, and 18 h/d) as independent variables to determine the optimal combination. Finally, a comparative grafting experiment was conducted between the seedlings cultivated using the optimal light formula and commercially available seedlings. The result showed that increasing light intensity inhibited hypocotyl length and promoted seedling stem growth, and excessive light intensity decreased seedling mechanical properties. The optimal light intensity for rootstocks is 200 μmol m−2 s−2, and the optimal light intensity for scions is 250 μmol m−2 s−2. Shortening the photoperiod would promote hypocotyl growth and inhibit seedling stem elongation. Different photoperiods had a significant impact on the mechanical properties of tomato seedlings. The most suitable photoperiod for rootstocks was 18 h/d and for scions was 16 h/d. The most suitable light formula was R:B = 50:50, 250 μmol m−2 s−2, 18 h/d. By analyzing the experimental results, the mechanical properties of seedlings grown by the regulated light environment were better than those of commercially available seedlings, and the success rate of mechanical grafting was 7% higher. Overall, in plant factories compared to commercially available tomato seedlings, tomato seedlings cultivated by the regulated light environment were more suitable for mechanical grafting. This research result provides theoretical support for subsequent research on grafting machinery. [ABSTRACT FROM AUTHOR]

According to the revised Andreasen-Andersen model, alkali activated mineral powder was used to completely replace cementitious materials to design the mix ratio of alkali activated ultra-high performance concrete. The impact of different water-binder ratios on the working performance and volume stability performance of ultra-high performance concrete (UHPC) was analyzed, and then the morphology of the alkali activated UPHC cross-section was analyzed using a scanning electron microscope. The results show that the unconfined compressive strength of alkali activated UHPC gradually increases with the decrease of water-binder ratio. The volume stability of alkali activated UHPC prepared by alkali activated mineral powder as cementing material is obviously improved. With the increase of curing age, the hydration products of alkali activated UHPC have more dense structure and excellent microstructure. [ABSTRACT FROM AUTHOR]

The mechanical properties of bolts are important factors affecting the shear behavior of bolted joints. In this study, tensile and pure shear tests were conducted on five kinds of bolts made from different materials to measure their tensile and shear parameters. Direct shear tests were conducted to analyze the effects of tensile and shear strength parameters on the shear behavior of bolted joints. The test results showed that the mechanical properties of bolts made from different materials were clearly different and that these differences mainly affected the plastic deformation stage of the bolted joints. The larger the bolt elongation was, the larger the joint shear displacement at bolt failure. The tensile and shear strengths of the bolts were positively correlated with the shear strength of the bolted joints. According to the standard regression analysis, the bolt shear strength had a greater influence than the bolt tensile strength on the bolt contributions when the bolts were perpendicular to the joint surface. Based on the empirical equation for the bolt contribution proposed by Spang, the maximum shear loads in the pure shear test were introduced, and a new equation was established to predict the contributions of bolts. The prediction results obtained using the modified equation were in good agreement with the experimental results. [ABSTRACT FROM AUTHOR]

Context and results: The structure, mechanical, electronic, vibration, and hydrogen bonding properties of a novel high-energy and low-sensitivity 5, 5′-dinitroamino-3, 3′-azo-oxadiazole 4, 7-diaminopyridazino [4, 5-c] furoxan salt have been studied by density functional theory. The calculated vibrational properties show that the low-frequency mode is mainly contributed by the vibration of the -NO2 group, and the high-frequency mode is mainly contributed by the vibration of the -NH2 group and the N7-H3 bond which protonates the cation. In addition, it is analyzed that the first bond to break may be the N-NO2 bond. The calculated hydrogen bond properties indicate that the hydrogen bond between water molecules and cations is N7-H3... O5 (1.563 Å), which is the shortest hydrogen bond among all hydrogen bonds. The presence of this exceptionally short hydrogen bond renders the N7-H3 and H6-O5 bonds resistant to disruption at high frequencies, underscoring the pivotal role of hydrogen bonding in stabilizing the structure of energetic materials. Given the absence of experimental and theoretical data on the electronic, mechanical, and vibrational properties of the material thus far, our calculations offer valuable theoretical insights into the ionic salts of high energy and low sensitivity. Computational methods: All calculations have been carried out based on density functional theory (DFT) and implemented in the CASTEP code. The mode-conserving pseudopotential is utilized to describe the plane wave expansion function, while the PBE functional within the generalized gradient approximation (GGA) is employed to characterize the exchange–correlation interaction. Additionally, dispersion correction is applied using Grimme's DFT-D method. [ABSTRACT FROM AUTHOR]

Carbon nanotubes (CNTs) are extensively utilized in the fabrication of high-performance composites due to their exceptional mechanical, electrical, and thermal characteristics. To investigate the mechanical properties of CNTs filled polymers accurately and effectively, a 3D modeling approach that incorporates the microstructural attributes of CNTs was introduced. Initially, a representative volume element model was constructed utilizing the modified nearest neighbor algorithm. During the modeling phase, a corresponding interference judgment method was suggested, taking into account the potential positional relationships among the CNTs. Subsequently, stress–strain curves of the model under various loading conditions were derived through finite element analysis employing the volume averaging technique. To validate the efficacy of the modeling approach, the stress within a CNT/epoxy resin composite with varying volume fractions under different axial strains was computed. The resulting stress–strain curves were in good agreement with experimental data from the existing literature. Hence, the modeling method proposed in this study provides a more precise representation of the random distribution of CNTs in the matrix. Furthermore, it is applicable to a broader range of aspect ratios, thereby enabling the CNT simulation model to more closely align with real-world models. [ABSTRACT FROM AUTHOR]