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BACKGROUND: The combination of machine learning and medical metal materials can make up for the inefficiency and high cost of traditional experiments and computational simulations, and quickly and accurately predict the characteristics of metal materials by analyzing large amounts of data, optimize material design and performance, and improve the safety and efficiency of medical applications. OBJECTIVE: To summarize the research progress and shortcomings of machine learning in the characteristics of medical materials. METHODS: The first author searched CNKI, PubMed, X-MOL, and Web of Science databases by computer to search all relevant articles from January 2013 to April 2023. The Chinese search terms were “machine learning of medical metal materials, medical titanium alloy, medical magnesium alloy, medical metal material properties”. The English search terms were “machine learning medical metal materials, medical stainless steel alloy, medical cobalt-chromium alloy, medical titanium alloy, medical magnesium alloy”. Finally, 70 relevant articles were included for a summary. RESULTS AND CONCLUSION: (1) The introduction of machine learning as a material design methodology has opened up new paradigms for material science research as the accessibility of large amounts of data generated by traditional experimental and computational simulation methods increases. (2) The machine learning workflow is divided into four main parts: data collection and preprocessing, feature engineering, model selection and training, and model evaluation, each of which is indispensable. (3) Medical metal materials are categorized into: stainless steel co-base alloys, cobalt-chromium alloys, titanium alloys, and magnesium alloys. For stainless steel co-base alloy, machine learning predicts its mechanical properties, to improve the generalization ability of machine learning. For cobalt-chromium alloy, machine learning predicts its mechanical properties, and it can conclude that cobalt-chromium alloy is the optimal material for hip implants. For titanium alloy, machine learning predicts its mechanical properties, and it can select the implant with the best mechanical properties. For magnesium alloy, machine learning predicts its corrosion resistance and mechanical properties; the ensemble model can accurately predict the mechanical properties of magnesium alloys, and the random forest model can predict the optimal elemental contents of magnesium alloys as vascular stents. (4) Machine learning has deficiencies in the field of medical materials. For example, the model is relatively lagging; the data failed to be standardized, and the generalization is low. To solve such problems, we should make full use of deep learning and segmentation algorithm technology, use unified standard data, and improve the model to increase the generalization ability. [ABSTRACT FROM AUTHOR]

To develop high-temperature structural materials with broadband microwave transmission ability used for high-speed aircraft radome, a sandwich-structured silicon nitride (Si 3 N 4) ceramic consisting of porous core and dense shell is designed based on CST simulation, which helps to obtain the optimized structural and dielectric properties. After that, its near-net-shape preparation strategy is presented by a controllable combined process including gel-casting (GC), polymer infiltration and pyrolysis (PIP), and chemical vapor deposition (CVD). The mechanical and electromagnetic performances were studied. The results show that the optimally-structured sandwich Si 3 N 4 processes a flexural strength of 216.5 MPa and a microwave transmissivity of 80 % in 2–13.4 GHz, which are obviously higher than that of traditional Si 3 N 4 ceramics. Besides, this sandwich-structured Si 3 N 4 ceramics also shows excellent dielectric and mechanical stabilities after a high-temperature oxidization at 1600 °C for 2 h in air atmosphere. Our prepared Si 3 N 4 ceramics achieves excellent mechanical strength, high microwave transmissivity, and good high temperature stability, indicating a great application potential as high-speed aircraft radome materials. [ABSTRACT FROM AUTHOR]

"The keyhole repair welding experiments were conducted on 5 mm thick BFel0-l-l copper-nickel alloy using the friction plug repar welding method. The study examined the micr-morphology, micr-hardness, temperature field distribution and mechanical properties of the plug repair welding joint at different spindle speeds. The results indicated that the spindle speed significantly influenced the plug welding form of the Copper-Nicke-Iron alloy. As the spindle speed increased, the weak connection defect at the bottom of the joint gradually diminished, the metal friction flow line in the plug area became more evident, and the gran was broken and reined. The heat affected zone was considerably reduced from the top to the bottom of the rewelded joint. Due to the fine gran s treng t hening, t he microhardness of t he plug zone was higher t han t ha t of t he base ma t eral, and t he microhardness of the upper side of t he plug zone was higher than that of the middle and lower side. The t ensile s trength of the joint was the highes t at 2 100 r/min, reaching 78% of t he base mat era. The joints showed duc tile fracture characteristics.With the increase of rotational speed, the weak connection defects of the joints gradually decreased and shrank. [ABSTRACT FROM AUTHOR]

Highlights This study aimed to explore the application of a mechanochemical method for effectively integrating polyimide nanofibers, which are widely recognized for their outstanding thermal and mechanical properties, into an epoxy resin matrix. The researchers observed an 87.5% reduction in the diameter of polyimide nanofibers after mechanical treatment. The dispersion, compatibility, and interface between the nanofibers and epoxy matrix were analyzed using molecular dynamics simulations and scanning electron microscopy. The addition of polyimide nanofibers significantly increased the binding energy of the composite, resulting in a 52.8% improvement. Moreover, compared to pure epoxy resin, the inclusion of modified polyimide nanofibers led to a 21.9% increase in tensile strength and an 18.8% increase in impact strength. The PI/epoxy composite also exhibited a 15.6% increase in tensile strength and a 16.4% increase in impact strength. Additionally, electrochemical corrosion analysis showed that the PI/epoxy composite had excellent corrosion resistance. In conclusion, due to the exceptional mechanical properties and strong interfacial adhesion of polyimide nanofibers, the PI/epoxy resin composite demonstrated significant overall performance improvement compared to pure epoxy resin. Mechanochemical method to disperse polyimide fiber, shorter and finer fibers were obtained Improve performance by adding small amounts Microscopic analysis of composites by Materials Studio, PIENFs efficiently improved the interaction on the phase interface Experiments have verified that PIENFs could make the mechanical properties and corrosion resistance [ABSTRACT FROM AUTHOR]

In this work, firstly, the zirconium-based MOF material UiO66-NH2 was synthesized and designed to obtain the PA functionalized MOF material UiO66-NH2-PA,which was then dispersed in an epoxy resin matrix to prepare carbon fiber/UiO66-NH2 epoxy composites with excellent properties. Subsequently, UiO66-NH2 as well as UiO66-NH2-PA were characterised by FT-IR,SEM and XRD,and the mechanical properties of the carbon fiber/UiO66-NH2 epoxy composites were tested using a universal testing machine. The results showed that UiO66-NH2-PA was successfully prepared and the bending and shear strength of the modified carbon fiber composites were increased by 26. 54% and 29. 09%,respectively. This was attributed to the enhanced interfacial strength by the action of amino and phosphorus groups in UiO66-NH2-PA,which enhanced both the energy storage modulus of the carbon fiber/UiO66-NH2 epoxy composites and the interfacial bonding ability of the composites, thus achieving the goal of improving the mechanical properties of carbon fiber and epoxy composites through the joint action. [ABSTRACT FROM AUTHOR]

Narrow gap welding of 316L stainless steel thick plate was carried out using the cold metal transition pulsed wire-arc swing method. The effects of heat input, arc swing, and shielding mode on weld shaping and lack of fusion were investigated, and microstructure and tensile properties of welded joints were analyzed and characterized. The results indicate that arc swing amplitude was the primary factor affecting sidewall fusion. The tendency of undercut and incomplete fusion at the weld toe increased with the increase of wire feeding speed. Narrow gap weld with built-in shielding was easy to produce pores. The microstructure of welded joints was mostly represented by twin crystals in HAZ and columnar dendrites in the weld. Solidification sub-boundaries were produced between dendritic crystal clusters in the middle of the weld under high heat input, resulting in severe regional segregation and crystalline cracks that extended along subgrain boundaries. The microhardness of the weld and HAZ was greater than that of the base material. The tensile strength of welded joints was comparable to that of base material with good mechanical properties. [ABSTRACT FROM AUTHOR]

Developing high-performance infrared radiation ceramic materials with desired broadband emissivity while reducing thermal conductivity to prevent heat transfer is highly desirable for emerging industrial and aerospace applications. Nevertheless, it remains a grand challenge to simultaneously meet these requirements in existing infrared radiation ceramic materials. Herein, a high-entropy strategy is employed to enhance the high-temperature infrared radiation property with a high emissivity above 0.9 at room temperature and 0.68 at 1200 °C across the entire range of wavelength (1–14 μm), and integrate a low thermal conductivity (<0.88 W m−1 K−1 at 1000 °C) and remarkable mechanical properties. High-entropy rare earth (RE) disilicates ((Y 0.4 Yb 0.4 Tm 0.1 Lu 0.05 Ho 0.05) 2 Si 2 O 7) ceramic coating with high lattice entropy has a more complex electronic structure, inducing lattice distortion and extra multi-mode vibrations, which boosts the emissivity in mid-infrared range (3–14 μm). Meanwhile, the high-entropy strategy prompts the formation of impurity energy levels as gap states, achieving optical absorption at low photon energies, and thus enhancing the emissivity in near-infrared range (1–3 μm). Simultaneously, (Y 0.4 Yb 0.4 Tm 0.1 Lu 0.05 Ho 0.05) 2 Si 2 O 7) ceramic coating owns diffusion-mediated thermal transport properties with strong phonon scattering, assisted further by the lamellar porous structure, thereby enabling a low thermal conductivity. The excellent mechanical properties ensure the reliability of the coating in extreme environments. All these merits render the high-entropy ceramic coating competitive for the development of high-temperature broadband high-emissivity thermal radiation materials. [ABSTRACT FROM AUTHOR]

Electrochemical co-deposition is a highly effective approach for achieving composites with specific composition and homogeneous distribution of reinforcement by manipulating electrolysis parameters. In this study, laminated carbon nanotubes reinforced copper composites (CNTs/Cu) were prepared through co-deposition and subsequent spark plasma sintering (SPS). In contrast to conventional powder metallurgy, the co-deposition method enables simultaneous deposition of CNTs and Cu particles while preserving the structural integrity of CNTs. It was observed that the CNTs were embedded within the growing Cu grains, resulting in a tightly bonded interface between them. The content of CNTs in composite deposited under current density of 0.5, 1.0 and 1.5 A⋅dm-2 is measured to be 0.51 vol%, 1.05 vol% and 1.31 vol%, respectively. The average grain size exhibited a significant reduction, decreasing from approximately 33.4 μm for pure Cu to 3.3 μm for the CNTs/Cu composite deposited under current density of 1.5 A⋅dm-2. Compared to pure Cu, the composite exhibited a significantly enhanced yield strength of 254 MPa, which is approximately 5 times that of pure Cu, the ultimate tensile strength improved to 290 MPa with an elongation of 15%, and the strengthening efficiency was calculated to be as high as 476. Load transfer is the primary contribution to the strength of the composites, followed by an increase in dislocation density and grain refinement. Meanwhile, the electrical conductivity of the composite with optimized condition demonstrated a high value of 94.4% IACS. The co-deposition method can facilitate the homogeneous dispersion of CNTs, enhance interfacial bonding, improve the structural integrity of CNTs, thereby enabling synergistic optimization of the properties of laminated CNTs/Cu composites. [ABSTRACT FROM AUTHOR]

• A model to explore the multiphysics characteristic of semiconductors is presented. • The model determines the thermal and mechanical properties of complex patterns. • Results show a strong correlation between thermal and mechanical properties. • Dielectric bands asymmetrically affect thermal and mechanical behavior. • Machine learning can predict one property from another. As semiconductor performance improves through advanced package designs, it becomes important to consider both thermal and mechanical properties. Better understanding their relationship enhances system design and optimization. This study has introduced a numerical method that takes into account both thermal and mechanical fluxes to construct thermal and mechanical property maps for practical application in semiconductor engineering. Furthermore, this paper investigated the relationship between the two properties using the constructed property maps in commercially available semiconductor packages. Owing to the complexity of packaging design patterns, a coupled isoparametric mapping and machine learning (ML) method was introduced to investigate their effects. The model then determines and investigates the anisotropic equivalent thermal and mechanical properties of the commercialized semiconductor packages with complex pattern designs, according to the package materials, volume fractions of each material, and design patterns. This approach pursues more sophistication and practicality compared to simplified composite structure property evaluation models. Additionally, all processes in the algorithm are automated based on ML methods, making them practically applicable in the semiconductor industry. The study shows that there is a strong correlation between the thermal and mechanical characteristics in the complex package patterns. This relationship was able to form a fairly clear category based on the shape of the dielectric band because the dielectric band had significantly different effects on the thermal and mechanical fluxes. The study discussed the physical implications of the similarities and differences between the two behaviors and validated the results of the equivalent properties through finite element (FE) analysis. Finally, the study cross-validates the relationship by showing that information from one flux behavior can be used to predict the other based on the ML method. Based on the results, this paper can provide a better understanding of thermal and mechanical fluxes in semiconductor package patterns for package design and optimization. [ABSTRACT FROM AUTHOR]

This study undertakes vacuum pressureless brazing of SiC ceramics with TiSi 2 powder, achieving MAX bonding. Microscopic characterization elucidates the microstructural evolution of the joined seam across various brazing temperatures and durations. The formation process of Ti 3 SiC 2 is detailed through thermodynamic and kinetic analyses. At 1550 ℃ for 30 min or 1600 ℃ for 15 min, the filler undergoes in-situ reaction with SiC, yielding a dense, continuous Ti 3 SiC 2 (MAX) phase, with no other phases observed. This suggests that increased temperature reduces MAX synthesis time. However, prolonged brazing causes voids in the center of the joined seam. Si volatilization was key for Ti 3 SiC 2 in-situ formation, and this reaction equation was proposed. Maximum average shear strength at room temperature is 127.15 MPa at 1550 ℃ for 30 min and 118.15 MPa at 1600 ℃ for 15 min. • In-situ formation of Ti 3 SiC 2 for pressureless joining of SiC ceramics. • Explain the growth principles of Ti 3 SiC 2 layer through the Ti-Si-C ternary phase diagram and kinetic principles. • Joint shear strength: 127.15 MPa. Explain strength variations using microscopic analysis. [ABSTRACT FROM AUTHOR]

Highlights Three‐dimensional molybdenum disulfide (MoS2) functionalized MWCNTs hybrid nanoparticles were synthesized using in‐situ hydrothermal reaction. Two types of hybrids, MoS2/MWCNTs‐1 and MoS2/MWCNTs‐2 with MWCNTs to MoS2 precursor weight ratios 1:2 and 1:1 respectively were prepared with varying degrees of hybridization and the effects of their incorporation on tensile strength and fracture toughness properties of epoxies were investigated. Epoxy/MoS2/MWCNTs‐2 nanocomposites showed exceptional mechanical properties due to their improved dispersion, constrained chain mobility and excellent interfacial interactions. MoS2/MWCNTs‐2 nanocomposites showed maximum improvement of tensile strength by 28.52% at 0.5 wt% nanofiller concentration and the highest improvements in fracture toughness by 172% at 0.2 wt% nanofiller concentration. The excellent enhancement of fracture toughness properties was due to the synergic effect of MoS2/MWCNTs hybrid nanoparticles due to the crack pinning and bifurcation properties of MoS2 nanoparticles along with the pull‐out and crack bridging mechanisms of MWCNTs as observed in morphological analysis of fractures nanocomposites. The incorporation of 0.2 wt% of MoS2/MWCNTs‐2 increased the degradation temperatures of epoxy from 591 to 796°C at 95% weight loss due to the improved physical barrier effect. MoS2/MWCNTs nanoparticles were synthesized using in‐situ hydrothermal reaction 0.5 wt% MoS2/MWCNTs‐2 incorporated epoxies showed highest tensile strength 0.2 wt% MoS2/MWCNTs‐2 incorporated epoxy composites show improved K1c value Incorporation of MoS2/MWCNTs improved the thermal stability of epoxy Synergistic effect of nanocomposite due to crack pinning, bifurcation & bridging [ABSTRACT FROM AUTHOR]

Highlights We herein report the enhancement of thermal, electrical, electromagnetic interference (EMI) shielding, and mechanical performance of polyethylene (PE) nanocomposites by the introduction of non‐covalently modified multi‐walled carbon nanotube (MWCNT) and ethylene‐glycidyl methacrylate (EGMA) copolymer. For this purpose, benzylacetic acid‐functionalized MWCNT (BA‐M) is prepared by ball milling, and it is melt‐mixed with EGMA to prepare a masterbatch. The masterbatch is then melt‐compounded with neat PE to manufacture a series of PE/EGMA/BA‐M nanocomposites with 0.5–5 wt% MWCNTs. Electron microscopic and spectroscopic analyses confirm the successful fabrication of non‐covalently functionalized BA‐M, the uniform dispersity of MWCNTs in the PE matrix, and the chemical reactions between the carboxylic acid groups of BA‐M and the epoxy group of EGMA in the nanocomposites. Scanning calorimetric data reveals that BA‐M acts as an efficient nucleating agent for the crystallization of PE. The excellent dispersity and robust interfacial bonding of BA‐M in the PE matrix result in improved electrical and EMI shielding properties in PE/EGMA/BA‐M nanocomposites. Furthermore, the tensile strength, initial modulus, and impact strength of the nanocomposites gradually rise as the BA‐M content increases. Thus, the PE/EGMA/BA‐M nanocomposite containing 5 wt% MWCNT achieves excellent performance of EMI shielding effectiveness of ~14.7 dB/mm, tensile strength of ~34.5 MPa, initial modulus of ~295.7 MPa, and impact strength of ~539.9 J/m, which represent enhancements of ~265%, ~40%, ~82%, and ~452%, respectively, compared to pristine PE. Non‐covalently modified MWCNT (BA‐M) was prepared by facile ball milling. PE nanocomposites with BA‐M and EGMA were prepared by masterbatch melt‐mixing. Excellent dispersity and interfacial bonding of MWCNT in the PE matrix were attained. Tensile strength and initial modulus of the nanocomposites were highly improved. EMI shielding effectiveness of the nanocomposite with 5 wt% MWCNT was ~14.7 dB/mm. [ABSTRACT FROM AUTHOR]

Highlights Fluorine rubber (FKM) stands as a pivotal sealing material extensively employed in aerospace and nuclear industries. However, its efficacy will be seriously affected by ionizing radiation. Enhancing its radiation resistance becomes imperative to uphold the stability and safety of associated equipment. This study introduced hexagonal boron nitride (h‐BN) into the FKM as radioprotective fillers through mechanical blending. The interfacial interaction between matrix and h‐BN, the mechanical performances, thermal properties, and radiation stability of composites were systematically examined. Noteworthy findings highlight the presence of robust interaction forces between h‐BN and the matrix, leading to increased crosslink density and improved mechanical properties. The tensile strength of composite with 10 phr fillers (BN/FKM‐10) increased by 30% compared to that of pure FKM. Simultaneously, the introduction of h‐BN greatly enhanced thermal conductivity and radiation stability. The absorbed dose required to achieve a 50% reduction in elongation at break of BN/FKM‐10 surpassed that of FKM by 1.69 times. These results underscore the potential of incorporating h‐BN to simultaneously enhance the mechanical performance, thermal property, and radiation resistance of fluorine rubber. The chemical interaction force between h‐BN and FKM was confirmed. FKM composites tensile strength was enhanced by h‐BN as an additive crosslinker. The incorporation of h‐BN improves FKM composites thermal conductivity. The radiation resistance of FKM composites has been improved with h‐BN. [ABSTRACT FROM AUTHOR]

Using first principles calculations, we systematically investigated the effects of strain engineering on the electronic, mechanical, and optical properties of two-dimensional (2D) orthorhombic III–V group materials, including BN, BP, BAs, AlN, AlP, and GaN. It is shown that all the III–V orthorhombic monolayers exhibit excellent mechanical anisotropy for Young’s modulus, Shear modulus, and Poisson’s ratio, especially for the AlN and GaN monolayers. AlN, AlP, and GaN are predicted to be indirect bandgap semiconductors, with their bandgap of 0.70, 0.15, and 0.53 eV, respectively. And BN is demonstrated to be a direct bandgap semiconductor (0.63 eV). Under uniaxial tensile strains, their electronic structures have non-monotonic anisotropic variations and these monolayers can be effectively modulated from metal to semiconductor, experiencing indirect–direct bandgap transitions. In addition, all the orthorhombic III–V materials exhibit highly anisotropic light-harvesting performances and the optical absorbance can be efficiently tailored with tensile strains applied along a- and b-directions. The strong optical absorptions in the visible light regions suggested that AlN, BN, and GaN may be optically tunable 2D materials for component absorbance layers for solar cell applications. The excellent anisotropic and tunable electronic, mechanical, and optical performances indicate that the orthorhombic III–V monolayers are promising candidates for potential applications of optoelectronics and photovoltaics. [ABSTRACT FROM AUTHOR]

Owing to its exceptional properties and wide‐ranging potential applications from aerospace to medicine, hexagonal boron nitride (h‐BN) has garnered considerable attention over the past decades. Boron nitride nanosheets (BNNSs), atomically thin h‐BN, not only inherit most of the outstanding properties of h‐BN but also exhibit superior characteristics compared to their bulk counterpart due to their reduced thickness, such as special adsorption behaviors and enhanced thermal conductivity. Furthermore, BNNSs display distinct thickness‐dependent properties from graphene and other 2D materials, such as unique mechanical response under indentation. This feature article provides an overview of the thickness‐related special properties of BNNSs, primarily derived from mechanically exfoliated h‐BN single crystals. These properties span various domains, including Raman signatures, molecule adsorption‐induced conformational changes, mechanical properties, thermal conductivity, and thermal expansion coefficients. Moreover, the feature article explores the underlying mechanisms governing these atomic‐scale thickness effects. Leveraging their unique properties, the feature article investigates diverse applications of BNNSs, encompassing surface‐enhanced Raman spectroscopy, metal‐enhanced fluorescence, and isotropic thermal management. [ABSTRACT FROM AUTHOR]

Cellulose-based biomass aerogels recently have garnered significant attentions as emerging materials for water treatment, due to their excellent characteristics of high porosity, lightweight structure, chemical modifiability and environmental friendliness. However, conventional freeze-drying methods have resulted in disordered pore structures of aerogels, reducing their mechanical property and water treatment efficiency. This article aims to provide a comprehensive review on the role of freeze-drying in cellulose-based aerogels. Special emphases are placed on freezing optimization strategies in aerogels preparations, such as co-solvent addition, directional freezing, freeze-thaw and soft-ice freezing, and water treatment applications of aerogels including oil-water separation, dye and heavy metal ions adsorptions, and seawater desalination via photothermal interfacial evaporation. The ordered pore structure constructed by freezing optimization can significantly increase the specific surface area and enhance the mechanical property of aerogels, thus improving the mass transfer rate and recyclability. The high-performance biomass aerogels prepared through freezing optimizations have shown a great application promise for biomass resources to achieve green and sustainable water treatment processes. [ABSTRACT FROM AUTHOR]

In this paper, an enhanced VARTM process is proposed and its pressure effect on resin infusion behavior and composite material performance is studied to reveal the control mechanism of the fiber volume fraction and void content. The molding is vacuumized during the resin injection stage while it is pressurized during the mold filling and curing stages via a VARTM pressure control system designed in this paper. Theoretical calculations and simulation methods are used to reveal the resin's in-plane, transverse, and three-dimensional flow patterns in multi-layer media. For typical thin-walled components, the infiltration behavior of resin in isotropic porous media is studied, elucidating the control mechanisms of fiber volume fraction and void content. The experiments demonstrate that the enhanced VARTM process significantly improves mold filling efficiency and composite's performance. Compared to the regular VARTM process, the panel thickness is reduced by 4% from 1.7 mm, the average tensile strength is increased by 7.3% to 760 MPa, the average flexural strength remains at approximately 720 MPa, porosity is decreased from 1.5% to below 1%, and the fiber volume fraction is increased from 55% to 62%. [ABSTRACT FROM AUTHOR]

Carbon fiber-reinforced resin matrix composites find extensive applications across various industries. However, their widespread use also generates significant waste, leading to resource depletion and environmental concerns. Studying the production of composite materials using recovered carbon fiber is imperative to mitigate the environmental impact associated with waste from carbon fiber-reinforced resin matrix composites and optimize resource utilization. In this study, carbon fiber was reclaimed using the microwave pyrolysis–oxidation process. The reclaimed carbon fiber underwent a cutting process to produce shorter carbon fibers tailored to specific requirements, which were then used to fabricate composite plates reinforced with epoxy resin. The mechanical characteristics of the composite were analyzed, along with SEM, XPS, infrared, Raman, and contact angle analyses conducted on the recovered carbon fiber. The test findings suggested minimal variation in the surface morphology of the recovered carbon fiber materials. Post-recovery, an increase in the quantity of oxygen-containing functional groups was observed on the carbon fiber surface. Additionally, the contact angle between the carbon fiber surface and the epoxy adhesive decreased. The mechanical properties of the composite produced from the recovered carbon fiber decreased, including the impact strength, tensile strength, and bending strength, with the impact strength dropping by 24.14%, tensile strength by 15.94%, and bending strength by 8.24%, while maintaining overall reusability, thus paving the way for the comprehensive utilization of carbon fiber resources. [ABSTRACT FROM AUTHOR]

Chromium slag is a solid waste of chromium salt production, which contains highly toxic Cr(VI) and significant amounts of valuable metals, such as Fe and Cr. Recycling chromium slag as a raw sintering material in sintering–ironmaking processes can simultaneously reduce toxic Cr(VI) and recover valuable metals. A micro-sintering experiment, compressive strength test, microhardness test, and first-principles calculation are performed to investigate the influence of Cr2O3 on the sintering microstructure and mechanical properties of the silico-ferrite of calcium and aluminum (SFCA) in order to understand the basis of the sintering process with chromium slag addition. The results show that the microstructure of SFCA changes from blocky to interwoven, with further increasing Cr2O3 content from 0 wt% to 3 wt%, and transforms to blocky with Cr2O3 content increasing to 5 wt%. Cr2O3 reacts with Fe2O3 to form (Fe1−xCrx)2O3 (0 ≤ x ≤ 1), which participates in forming SFCA. With the increase in Cr doping concentrations, the hardness of SFCA first decreases and then increases, and the toughness increases. When Cr2O3 content increases from 0 wt% to 3 wt%, the SFCA microhardness decreases and the compressive strength of the sintered sample increases. Further increasing Cr2O3 contents to 5 wt%, the SFCA microhardness increases, and the compressive strength of sintered sample decreases. [ABSTRACT FROM AUTHOR]

The effects of austenitizing and austempering temperatures on the bainite transformation kinetics and the microstructural and mechanical properties of a medium-carbon high-silicon ultra-fine bainitic steel were investigated via dilatometric measurements, microstructural characterization and mechanical tests. It is demonstrated that the optimum austenitizing temperature exists for 0.3 wt.%C ultra-fine bainitic steel. Although the finer austenite grain at 950 °C provides more bainite nuclei site and form finer bainitic ferrite plates, the lower dislocation density in plates and the higher volume fraction of the retained austenite reduces the strength and impact toughness of ultra-fine steel. When the austenitizing temperature exceeds 1000 °C, the true thickness of bainitic ferrite plates and the volume fraction of blocky retained austenite in the bainite microstructure increase significantly with the increases in austenitizing temperature, which do harm to the plasticity and impact toughness. The effect of austempering temperature on the transformation behavior and microstructural morphology of ultra-fine bainite is greater than that of austenitizing temperature. The prior martensite, formed when the austempering temperature below Ms, can refine the bainitic ferrite plates and improve the strength and impact toughness. However, the presence of prior martensite divides the untransformed austenite and inhibits the growth of bainite sheaves, thus prolonging the finishing time of bainite transformation. In addition, prior martensite also strengthens the stability of untransformed austenite though carbon partition and enhances the volume fraction of blocky retained austenite, which reduces the plasticity of ultra-fine bainitic steel. According to the experimental results, the optimum austempering process for 0.3 wt. %C ultra-fine bainitic steel is through austenitization at 1000 °C and austempering at 340 °C. [ABSTRACT FROM AUTHOR]

Single-pass-welding thermal cycles with different peak temperatures (Tp) were reproduced by a Gleeble 3800 to simulate the heat-affected zone (HAZ) of a Fe-24Mn-4Cr-0.4C-0.3Cu (wt.%) high manganese austenitic steel. Then, the effect of Tp on the microstructure and mechanical properties of the HAZ were investigated. The results indicate that recrystallization and grain growth play dominant roles. Based on this, the HAZ is proposed to categorize into three zones: the recrystallization heat-affected zone (RHAZ) with a Tp of 700~900 °C, the transition heat-affected zone (THAZ) with a Tp of 900~1000 °C, and the coarse grain heat-affected zone (CGHAZ) with a Tp of 1000~1300 °C. The recrystallization fraction was 29~44% in the RHAZ, rapidly increased to 87% in the THAZ, and exceeded 95% in the CGHAZ. The average grain size was 17~19 μm in the RHAZ, slightly increased to 22 μm in the THAZ, and ultimately increased to 37 μm in the CGHAZ. The yield strength in the RHAZ and THAZ was consistent with the change in recrystallization fraction, while in the CGHAZ, it satisfied the Hall–Petch relationship with grain size. In addition, compared with the base material, the Charpy impact absorbed energy at −196 °C decreased by 22% in the RHAZ, but slightly increased in the CGHAZ. This indicates that the theory of fine grain strengthening and toughening is not entirely applicable to the HAZ of the investigated high-Mn steel. [ABSTRACT FROM AUTHOR]

In this study, the vat photopolymerization (VP) additive manufacture technique was employed to fabricate Si 3 N 4 ceramics implants. A photosensitive suspension with a high solid loading of 40 vol% and a low viscosity of 1.95 Pa•s at a shear rate of 30 s−1 was achieved by optimization of the composition. Particularly, as high as 50 vol% content of PPG was used in the photosensitive suspension, leading to a smooth printing and increased debinding efficiency with a heating rate up to 3 °C/min. The printed body was sintered at 1800 °C under 0.4 MPa nitrogen atmosphere, obtained the Si 3 N 4 ceramic with a relative density of 96.08%, a fracture toughness of 5.88 MPa m1/2, a flexural strength of 677 MPa and a Vickers hardness of 16.26 GPa. A cylindric Si 3 N 4 ceramic implant was made by the optimized suspension and printing parameters, and the implantation test in the histological section was conducted, showing a good biocompatibility after 6 weeks. [ABSTRACT FROM AUTHOR]

This study shows the beneficial properties of using (Li 2 Mn 4)O(CO 3) 4 ·H 2 O (P–LiMn 2 O 4) as an anti-ablation additive in silicone rubber, effectively inhibiting ablation at all temperature ranges studied, indicating its potential as a valuable material. The experimental results show that P–LiMn 2 O 4 enhances the anti-ablation process of silicone rubber through several mechanisms, including dehydration, decarbonization, gas production, and solid-solid phase change. These mechanisms induce heat absorption, gas film formation and ceramic phase formation. Furthermore, P–LiMn 2 O 4 effectively improves the resistance of silicone rubber to ablation without compromising its mechanical properties. This study presents a method to enhance ablation resistance through multiple pathways, which can extend the application of phase change materials under extreme thermal conditions. [ABSTRACT FROM AUTHOR]

The progress of stretchable and wearable photovoltaics relies heavily on intrinsically stretchable active layer films. Nevertheless, there is a paucity of research clarifying the connections between their microstructure, performance, and their adaptation to large strain in polymer electronic films. The current study utilizes multiple synchrotron X‐ray scattering methods to collectively examine the correlations between morphology and stretchability, as well as the microstructural evolution induced by stretching in three sample cases of highly stretchable ternary blend films. These blends contain over 30% by weight of a polymer elastomer, such as styrene‐ethylene‐butylene‐styrene block copolymer, integrated into the high‐performance polymer:nonfullerene small molecule mixture. Specifically, the real‐time microstructural changes of these durable organic photovoltaic films with elastomers are monitored when subjected to tensile stretching through in situ synchrotron X‐ray scattering. The experiments demonstrate that polymeric elastomers can effectively lower the degree of crystallinity in films and deform the crystallites of semiconductor molecules. The elastomeric component aids in stress dispersion during stretching, thereby improving the microstructural durability of blend films. This study provides new recommendations for advancing stretchable organic optoelectronic devices. [ABSTRACT FROM AUTHOR]

High entropy carbide ceramics have attracted much attention because of their high hardness and chemical inertness, but the relatively low fracture toughness limits their actual industrial applications. In this work, high entropy (MoTaTiVW)C 5 ceramics reinforced with silicon carbide whisker (SiC w) were fabricated with spark plasma sintering. The effects of SiC w contents and sintering temperatures on the microstructure and mechanical properties of (MoTaTiVW)C 5 have been studied. The outcomes show that by optimizing the sintering temperature, a dense microstructure with intact SiC w were obtained which could fully utilize the toughening effect of the SiC w and thus exhibits an enhanced mechanical property. Additionally, the presence of solid solution oxide particles in the sintered bulks is also beneficial for the improved toughness. The sample with 5 wt% SiC w sintered at 1700 °C exhibited higher hardness of 19.63 GPa and fracture toughness of 6.26 MPa m1/2, which is attributed to the combined toughening effects (crack deflection, crack bridging, and whisker/particle extraction) of SiC w and oxide particles. The findings contribute to the development of advanced ceramic materials with improved mechanical properties for various applications. [ABSTRACT FROM AUTHOR]

Magnesium (Mg) alloys are becoming popular in lightweight manufacturing due to their low density and high specific strength. However, insufficient slip systems result in poor plasticity of Mg alloys at room temperature. Therefore, an ultrasonic energy field combined with thermal field is introduced to assist the deformation of AZ31 Mg alloy to improve its plasticity. Firstly, ultrasonic vibration (UV)-assisted tensile tests at different temperatures (130e150 °C) are conducted to investigate the effect of UV on material behaviour and the activation of dynamic recrystallization (DRX). Then, the influences of UV on the mechanical properties and microstructure of the material at 150 °C are investigated by varying the parameters of ultrasound amplitude, strain rate, and vibration interval. The results reveal that applying UV can activate DRX at a relatively lower temperature compared with that without UV. Superimposing a certain amount of ultrasonic energy on this material at warm conditions reduces flow stress and increases elongation. In the intermittent ultrasonic vibration (IUV) tests, the DRX percentage and elongation first increase and then decrease as the vibration interval increases. The elongation of specimens with appropriate vibration intervals even exceeds that of specimens with continuous ultrasonic vibration (CUV). However, CUV is more effective than IUV in reducing ultimate tensile strength at different amplitudes or strain rate. [ABSTRACT FROM AUTHOR]

High flame retardancy, satisfactory mechanical properties are crucial for polymeric composites employed in fields with safety requirements. Inorganic fillers can effectively regulate the structure and composition of polymeric materials and have become an effective strategy for fabricating high-performance polymeric composites. Herein, aluminum phosphate–coated sepiolite (Sep@AlPO4) fillers are fabricated as a multifunctional additive to modify polyethylene oxide (PEO), PEO nanocomposites were prepared via incorporation of Sep@AlPO4 and phenethyl-bridged 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) derivative (DiDOPO) in the PEO matrix, and the synergistic effects between Sep and AlPO4 are discussed. The results reveal that Sep@AlPO4 could simultaneously enhance the flame retardancy and strengthen the mechanical properties of PEO/DiDOPO. Additionally, Sep@AlPO4 could increase the viscosity, storage modulus, and loss modulus of the composites. This study provides an effective strategy for fabricating enhanced flame retardants to improve the performance of polymers. [ABSTRACT FROM AUTHOR]

Open tunnel boring machine(TBM), known for their characteristics such as high speed, low impact, and excellent efficiency, are increasingly being widely applied in underground construction. However, as China intensifies its efforts in developing infrastructure and energy projects in the western regions, construction processes are encountering more and more weakly cemented sandstone formations. The application of open TBM in these formations presents significant challenges, often leading to issues like roof collapses, sidewall instability, and insufficient ground support. To expedite production, the open TBM will be applied worldwide for the first time in the inclined shaft excavation of the Kekegai coal mine. Given the low strength, weak cementation, and high groundwater flow in the Luohe Formation, extensive research has been conducted, building upon previous studies. Various research methods, including field measurements and laboratory tests, were employed to investigate the physical properties, microstructures, mineral composition, water content, and pore structure of the water-rich, weakly cemented sandstone in the Luohe Formation. The test results indicate that the porosity of this formation reaches 25. 6%, with strong permeability, and contains approximately 15% clay minerals, suggesting some expansiveness. It is recommended to use ultra-permeable nanometer-grade grouting materials to improve grouting effectiveness. Subsequently, triaxial compression tests were conducted under different moisture content and confining pressure conditions, demonstrating that increasing radial stress has a significant effect on controlling the surrounding rock. Innovative support optimization measures were proposed, including “advance reinforcement + anchor cable mesh + nanometer-grade slurry grouting”. Numerical simulations and field applications have shown a significant improvement in rock fragmentation and deformation after optimization, resulting in an increase in the actual excavation rate from 10 m/ d to 17 m/ d, greatly enhancing excavation efficiency and safety. [ABSTRACT FROM AUTHOR]

The mechanical properties and nonlinear performance of the Q960 cold-formed thick-walled ultra-high-strength steel (CTUS) after elevated temperatures were investigated experimentally, where the effects of cold-forming process, elevated temperature, and cooling condition were considered. Seven different elevated temperatures and two different cooling conditions were included in experiment, where a total of 45 coupon specimens were tested. The tensile coupon test was performed on the Q960 CTUS specimens to reveal the influences of the elevated temperature and cooling condition on the residual stress–strain properties. The predictive equations for the key mechanical parameters of the Q960 CTUS after elevated temperatures were proposed based on the experimental results. The mechanical properties of the Q960 CTUS after elevated temperatures were compared with those of different structural steels and reinforcing steels. A reliability analysis was performed to determine the accuracy of predictive equations for key mechanical parameters, where the resistance factor was recommended. A constitutive model was suggested to elucidate stress–strain curves of the Q960 CTUS after elevated temperatures. These research findings served as the foundation for the future numerical and theoretical investigations on the residual resistant performance of the Q960 CTUS structures after fire. [ABSTRACT FROM AUTHOR]

Using biodegradable films as a substitute for conventional polyolefin films has emerged as a crucial technology to combat agricultural white pollution. To address the shortcomings in the tensile strength, water vapor barrier properties, and degradation period of PBAT-based biodegradable films, this investigation aimed to create a composite film that could improve the diverse properties of PBAT films. To achieve this, a PBAT/PLA-PPC-PTLA ternary blend system was introduced in the study. The system effectively fused PBAT with PLA and PPC, as evidenced by electron microscopy tests showing no apparent defects on the surface and cross-section of the blended film. The developed ternary blend system resulted in a 58.62% improvement in tensile strength, a 70.33% enhancement in water vapor barrier properties, and a 30-day extension of the functional period compared to pure PBAT biodegradable films. Field experiments on corn crops demonstrated that the modified biodegradable film is more suitable for agricultural production, as it improved thermal insulation and moisture retention, leading to a 5.45% increase in corn yield, approaching the yield of traditional polyolefin films. [ABSTRACT FROM AUTHOR]

Considering the different structural strength requirements of different parts of fiberglass yachts, carbon fiber/glass fiber hybrid reinforcement can be applied to the skins of sandwich panels in special areas. This paper designs and prepares 12 foam sandwich panel samples composed of pure carbon fiber, a carbon fiber/glass fiber hybrid, pure glass fiber skin, and PVC and SAN foam sandwich, with reference to the layup structure of the outer panel of a fiberglass yacht. Through a comparative analysis of low-speed impact experiments, edge compression experiments, and short beam three-point bending experiments, we seek the optimal carbon fiber/glass fiber hybrid layup design scheme for local structures to guide production. The results show that a reasonable hybrid carbon fiber layup in fiberglass skin can effectively reduce the low-speed impact damage of the sandwich structure, reduce edge compression damage, and improve the bending and compression resistance of sandwich structure. The impact resistance, compression resistance, and shear resistance of the SAN sandwich structure are stronger than the PVC sandwich structure. The carbon fiber/glass fiber hybrid SAN foam sandwich structure can be used for the local structural reinforcement of special parts such as the bow, side, and main deck of fiberglass yachts. [ABSTRACT FROM AUTHOR]

Considering the high-speed and high power density technical specifications of new energy vehicle motors, there is a growing demand for rotor strength as motor peak speeds reach 20,000 r/min and beyond. The utilization of non-oriented silicon steel with a high yield strength in rotors has emerged as a promising approach to increase motor speed. However, the magnetic and mechanical properties of high-strength silicon steel under variable temperature conditions have not been fully explored, particularly in regards to their impact on motor torque, efficiency, and speed. This manuscript investigates the behavior of high-strength silicon steel before and after annealing and at different temperatures, analyzing its influence on high-speed motor performance. The validity and feasibility of this study are confirmed through prototype testing, providing a comprehensive reference for engineering design. [ABSTRACT FROM AUTHOR]

Materials with monolithic structures, such as epoxy monoliths, are used for a variety of applications, such as for column fillers in gas chromatography and HPLC, for separators in lithium-ion batteries, and for precursor polymers for monolith adhesion. In this study, we investigated the fabrication of epoxy monoliths using 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane (TETRAD-C) as the tetrafunctional epoxy and 4,4′-methylenebis(cyclohexylamine) (BACM) as the amine curing agent to control pore diameters using polyethylene glycols (PEGs) of differing molecular weights as the porogenic agents. We fabricated an epoxy monolith with micron-order pores and high strength levels, and which is suitable for the precursors of composite materials in cases where smaller PEGs are used. We discussed the effects of the porous structures of monoliths on their physical properties, such as tensile strength, elongation, elastic modulus, and glass transition temperatures. For example, epoxy monoliths prepared in the presence of PEGs exhibited an elastic modulus less than 1 GPa at room temperature and Tg values of 175–187 °C, while the epoxy bulk thermoset produced without any porogenic solvent showed a high elastic modulus as 1.8 GPa, which was maintained at high temperatures, and a high Tg of 223 °C. In addition, the unique adhesion characteristics of epoxy monolith sheets are revealed as a result of the combinations made with commercial epoxy and acrylic adhesives. Epoxy monoliths that are combined with conventional adhesives can function as sheet-type adhesives purposed with avoiding problems when only liquid-type adhesives are used. [ABSTRACT FROM AUTHOR]

Friction stir lap welding experiments between 6061 aluminum alloy plate and DP590 dual-phase steel plate were carried out. The effects of welding parameters and addition of Ni foil interlayers with different thickness on the microstructures and mechanical properties of the lap joints were investigated. The shear strength of the joint reached the maximum value of 6597 N and showed a mixed ductile-brittle fracture mode when the welding speed, the rotating speed and the thickness of the Ni foil intermediate layer were set to 100 mm/min, 900 rpm and 0.3 mm, respectively. A certain amount of beneficial plastic AlNi and FeNi3 intermetallic compounds are formed through the reaction of Al, Fe and Ni at the aluminum alloy/steel interface. [ABSTRACT FROM AUTHOR]

The pia-arachnoid complex (PAC) tissue plays a vital role in upholding the physiological functionality of brain tissue and bolstering its capacity to withstand detrimental loads. However, the mechanical attributes of the PAC tissue remain inadequately comprehended and insufficiently explored. This investigation acquired the indentation response of the PAC tissue through large deformation dynamic indentation. The mechanical significance in the face of external loads of the PAC tissue was elucidated through the combination of finite element simulation and experiment. The findings demonstrated that the PAC tissue can augment the cortex's shear modulus and damping ratio, fortifying the brain tissue's resistance against deformation. Additionally, the outcomes revealed that the PAC tissue can curtail the maximum stress and strain within the brain tissue by 40% and 53%, respectively, when subjected to substantial local deformation. Furthermore, the PAC tissue can impede strain propagation to the cerebral cortex during relaxation. This inquiry furnished a fundamental dataset for characterizing the dynamic mechanical properties within finite element simulations and experimental explorations involving brain tissue. [ABSTRACT FROM AUTHOR]

AbstractIntegrated zirconium (Zr) alloy fuel claddings require low-temperature and high-efficiency joining technologies for nuclear applications. However, conventional direct-joining technologies make it challenging to satisfy critical requirements at relatively low temperatures in a short time. As a promising alternative, the electric-current-assisted joining (ECAJ) method was studied to reduce the joining temperature and time required for the direct joining process. ECAJ was performed on a spark plasma sintering apparatus, with the specimens assembled with and without graphite dies in the two models. The microstructural evolution and mechanical properties of Zr/Zr joints were investigated at 600 − 900 °C for 1 s to 30 min under a pressure of 30 MPa using different configurations with or without a graphite die. While the joint quality varied with the joining conditions, no significant phase transformation, abnormal grain growth, or preferential orientation was observed at the interface. The maximum shear strength of 404 ± 78 MPa and hardness of 370.9 ± 49.8 HV were achieved at 600 °C for 10 min using a die-less configuration. The joining mechanism was discussed in terms of the potential thermal and electric effects inside the specimen, with the low-temperature joining mechanism attributed to the combined effect of transient overheating and electric-field-accelerated element self-diffusion at the interface, with the latter playing a leading role. [ABSTRACT FROM AUTHOR]

The corn variety “Zhenghong 507”, which is widely cultivated in hilly and mountainous areas of Southwest China, was assigned as the research object. The discrete element model of the mid-section of the corn ear that can be threshed was established by integrating the Hertz-Mindlin with the bonding V2 contact model, and the crucial bonding parameters were simulated and calibrated. With the measured normal threshing force (6.34 N) and tangential threshing force (4.75 N) of a single kernel as target values, the parameters of bonding characteristics between the kernel and the cob of corn ear were screened and optimized for significance via the Placket-Burman test, steepest ascent test, and the central composite design. The results indicate that the optimal parameter combinations for the normal stiffness and shear stiffness per unit area, normal strength, shear strength, contact radius between kernels, contact radius between cobs, and bonded disk scale were 3.4 × 108 N·m−3, 2.238 × 108 N·m−3, 0.6 × 106 Pa, 0.364 × 106 Pa, 1.87 mm, 16.5 mm and 1.321. Finally, the accuracy of the corn ear DEM model was validated by comparing the simulation to the physical test using the threshing rate as an evaluation index combined with the quality distribution of kernels after threshing. [ABSTRACT FROM AUTHOR]

Al2O3f/SiO2 composites were fabricated by sol–gel process, with a density of 2.22 g/cm3, pyro carbon coating prepared via chemical vapor deposition. The interfacial bonding strength between the fiber and matrix was weakened, and the brittle fracture characteristics of the fiber under a high‐temperature environment were improved, ensuring the integrity and reliability of the structure. The mechanical property and failure mechanism of the composites were investigated using acoustic emission technology (AE). In the tensile test, microcracks first appeared in the sample matrix, followed by matrix damage, fiber matrix debonding, and partial fiber fracture near the peak load. It was worth noting that many fibers remained undamaged when the load suddenly declined. As the loading continued, these fibers were fully pulled out and consequently loaded until they gradually broke. In the shear test, the load increased to its peak and decreased rapidly, and the proportion of the AE signal generated was extremely small (≤.01). Owing to the brittleness of the matrix under shear force, the crack easily expanded along the interlayer instability such that the sample first showed significant interlayer damage. [ABSTRACT FROM AUTHOR]

Previous studies have indicated that hydratable magnesium carboxylate (HMC) exhibits potential as an MgO‐based binder, but its limited medium‐temperature strength has hindered its widespread industrial application. In this study, the incorporation of MgO fumes into castables is intended to react with microsilica to form magnesium–silicate–hydrate (M–S–H), and the synergistic effect of HMC and M–S–H is anticipated to improve the mechanical properties of castables at intermediate temperatures. The effects of MgO fumes on the properties of HMC‐bonded castables were comprehensively investigated. The results demonstrate that incorporating MgO fumes into castable serves multiple functions. The ionized MgOH+ from MgO fumes hinders the hydration process of HMC, prolonging the final setting time from 13 to 98 min and improving the workability of castables. The incorporation of MC‐1100 enhanced mechanical properties at medium temperature due to the synergistic effects of brucite, HMC, and M–S–H. Specifically, the CMOR increased 20% after sintering at 800°C. Furthermore, adding MC‐1100 increases the residual strength rate of castable by 10% compared to those without MgO fumes. This can be attributed to enhanced spinel formation resulting from adding MgO fumes that improves elastic modulus and reduces elastic strain energy generation during thermal shock, thus increasing crack propagation resistance. [ABSTRACT FROM AUTHOR]

In this paper, by adding Co, Mo, and Ni metal binder and using spark plasma coupling high-frequency induction (SP–HF) sintering technology, high-entropy (W,Nb,Mo,Ta,Ti)C cermet with good performance was successfully prepared at 1350 °C. The sintering temperature was much lower than that of the solid-state sintering temperature adopted for high-entropy carbide ceramics (about 2000 °C) while maintaining high hardness and fracture toughness. The effects of sintering temperature, holding time and sintering pressure on the mechanical properties of high-entropy (W,Nb,Mo,Ta,Ti)C cermet were investigated. The experimental results show that the SP-HF sintering can promote the liquid phase flow inside the high-entropy (W,Nb,Mo,Ta,Ti)C cermet and improve the density. The high-frequency induction sintering effect of the high-intensity magnetic metal binder phase (Co, Ni) promotes the rapid diffusion of the constituent phases using the vacancy mechanism and the metal liquid phase, which helps to form a high-entropy cermet solid solution at a lower temperature. The different high-entropy effects of the inner and outer layers of high-entropy (W,Nb,Mo,Ta,Ti)C cermet materials play a role in strengthening and toughening the materials, and effective solid solution strengthening is the main reason for improving mechanical properties. The mechanical properties of high-entropy (W,Nb,Mo,Ta,Ti)C cermet are the optimized at 1350 °C, holding time of 8 min, and sintering pressure of 35 MPa. The Vickers hardness, fracture toughness, and flexural strength are 18.38 ± 0.19 GPa, 9.65 ± 0.25 MPa · m1/2 and 970 ± 30 MPa, Vickers hardness was measured at 49 N load. [ABSTRACT FROM AUTHOR]

[Display omitted] Poor mechanical strength at working temperature and low ionic conductivity seriously hinder the application of poly(ethylene oxide) (PEO)-based solid polymer electrolytes (SPEs) in high performance all-solid-state lithium metal batteries (LMBs). Here, we design and prepare a series of rigid-flexible coupling network SPEs (RFN-SPEs) with soft poly(ethylene glycol) (PEG) chains and rigid crosslinkers containing the benzene structure. Compared with soft crosslinkers, rigid crosslinkers provide the same amount of active crosslinking points with smaller molecular weight, and meanwhile enhance the mechanical strength of the network. Therefore, based on the rigid crosslinkers, RFN-SPEs exhibit synchronously improved ionic conductivity and mechanical strength. With these RFN-SPEs, symmetrical cells can be cycled for over 2100 h at 0.5 mA cm−2. Meanwhile, stable cycling and high-rate capability could be achieved for LMBs, revealing that SPEs with the rigid-flexible coupling network are promising electrolyte systems for all-solid-state LMBs. [ABSTRACT FROM AUTHOR]

The direct welding of alumina ceramic and titanium using ultrashort pulse laser was successfully achieved for the first time. Benefitting from the extremely high peak power of ultrashort pulse laser, ceramics can be melted at a very low laser power. The emerging welding method was conducted at room-temperature without the need for preheating. Within the joint, a combination of Ti and Al elements was observed. A newly formed TiO 2 phase was identified at the Al 2 O 3 /welding seam interface. Under the optimal welding parameters (welding speed: 0.8 mm/s, laser power: 19.52 W), the joint achieved a maximum four-point bending strength of approximately 134.9 MPa. This study proposed a new methodology for butt welding of ceramics and metals and shows a much higher efficiency than the commonly used ceramic-metal joining approaches such as brazing and diffusion bonding. [ABSTRACT FROM AUTHOR]

Graphite is a widely used oxygen impurity-removing additive and a property-tuning second phase for diboride and carbide-based ultrahigh temperature ceramics (UHTCs). In recent years, high-entropy diboride (HEB) ceramics have attracted much attention for the development of better UHTCs. However, oxide impurity generally inhibits their densification and harms their properties. Here, (Ti 0.2 Zr 0.2 Hf 0.2 Nb 0.2 Ta 0.2)B 2 ceramics added with different contents of graphite (HEB- x C, x = 0, 1, 2.5, 5, 10, 20 vol%) were prepared by spark plasma sintering. It was found that the added graphite acted as an oxygen-removing agent and the oxide impurity phase t -(Zr, Hf)O 2 was converted to the (Hf, Ta)C-based solid solution carbide. With the increase in graphite content, the relative density increased from 89.4% for HEB-0 C to 100% for HEB-10 C. Based on the evaluated properties of the prepared specimens, including Young's modulus, hardness, toughness, and thermal conductivity, the added graphite with an optimized content is important for a given started powder and processing to achieve good and balanced material properties. [ABSTRACT FROM AUTHOR]

AbstractCompressive tests, tensile tests, and scanning electron microscopy (SEM) tests were performed on polypropylene fiber recycled concrete (PFRC) after freeze–thaw cycles. The effects of the replacement percentage of recycled coarse aggregate (RCA) and the addition percentage of fiber on strength characteristics were analyzed. The variation rules of strength and failure modes after freeze–thaw cycles were described. The development of stress–strain curves and deformations were observed at different times of freeze–thaw cycles. The experimental results showed that the compressive and tensile strength both present a trend of first increasing and then decreasing with the increase addition percentage of fiber or the replacement percentage of RCA. The optimum mix proportion of RCPP30-0.1 was obtained. The tensile and compressive strength both reduced as the times of freeze–thaw cycles increased. After 75 times, the strength dropped by 6.37% and 4.52% compared with that at 0 time of cycles, respectively. Overall, freeze–thaw cycles have adverse effects on the mechanical properties of PFRC. Based on the theoretical analysis of experimental data, prediction models on macroscopic and microscopic properties were established in this study, which can help promote more extensive applications of RAC and realize persistent development strategy of building, resources, and environment to a certain extent. [ABSTRACT FROM AUTHOR]

The complex ceramic core used for hollow turbine blades requires high porosity and flexural strength. This work combined vat photopolymerization 3D printing with sacrificial template method to prepare Al2O3 ceramic cores with strip‐shaped pores using polyamide 6 (PA6) fibers as templates. When the porosity was greater than 30%, the maximum flexural strength reached up to 110.48 MPa. The sacrificial templating method improved the porosity of Al2O3 ceramic cores, forming an internal porous structure that combined strip‐shaped large pores with irregularly shaped small pores. The influences of PA6 fiber content and diameter on the shrinkage, porosity, microstructure, and comprehensive properties of alumina ceramic cores were studied, revealing the mechanism of the coexistence of high porosity and high strength. [ABSTRACT FROM AUTHOR]

A non-pneumatic tire (NPT) overcomes the shortcomings of a traditional pneumatic tire such as wear, punctures and blowouts. In this respect, it shows great potential in improving driving safety, and has received great attention in recent years. In this paper, a carbon fiber-reinforced polyethylene terephthalate (PET/CF) honeycomb is proposed as a support structure for NPTs, which can be easily prepared using 3D printing technology. The experimental results showed that the PET/CF has high strength and modulus and provides excellent mechanical properties. Then, a finite element (FE) model was established to predict the compression performance of auxetic honeycombs. Good agreement was achieved between the experimental data and FE analysis. The influence of the cell parameters on the compressive performance of the support structure were further analyzed. Both the wall thickness and the vertically inclined angle could modulate the mechanical performance of the NPT. Finally, the application of vertical force is used to analyze the static load of the structure. The PET/CF honeycomb as the support structure of the NPT showed outstanding bearing capacity and stiffness in contrast with elastomer counterparts. Consequently, this study broadens the material selection for NPTs and proposes a strategy for manufacturing a prototype, which provides a reference for the design and development of non-pneumatic tires. [ABSTRACT FROM AUTHOR]

The extruded Mg–6Bi alloy and Mg–6Bi–1Ag alloy subjected to extrusion at 300 °C with the extrusion ratio of 25:1 and die-exit speed of 2 m/min were used to investigate microstructure characteristics and mechanical behavior. The experimental results demonstrate that the bimodal microstructure, composed of coarse dynamic unrecrystallized (unDRXed) grains and fine dynamic recrystallized (DRXed) grains, was obtained after extrusion. The Ag addition can obviously promote dynamic recrystallization and average grain size. It also indicates that the dynamic precipitation is significantly promoted by Ag addition during extrusion, obtaining more fraction of the Mg3Bi2 precipitates. Moreover, the extruded Mg–6Bi–1Ag alloy has a high tensile yield strength of 304 ± 2.0 MPa, which is increased by 19% compared to the extruded Mg–6Bi alloy, and elongation of 11.0 ± 1.7%, almost the same as 11.9 ± 0.9% of the extruded Mg–6Bi alloy. This result also shows that the extruded Mg–6Bi–1Ag alloy exhibits better strain hardening capacity. Therefore, Ag exhibits an effective role in promoting dynamic recrystallization and dynamic precipitation, resulting in the enhancement of strength and strain hardening capacity of the extruded Mg–6Bi–1Ag alloy, as well as keeping high ductility. [ABSTRACT FROM AUTHOR]

Retrogression and re-aging (RRA) treatment has been proven to effectively overcome the trade-off between strength and corrosion resistance. Current research focuses on the heating rate, temperature, and holding time of retrogression treatment while ignoring the retrogression cooling ways. In this paper, the effects of RRA treatment with different retrogression cooling ways on the microstructure and properties of newly developed T'/η' strengthened Al-Zn-Mg-Cu alloys were investigated by performing tests on mechanical properties, intergranular corrosion (IGC) resistance, and electrochemical corrosion behavior. The results show that the mechanical properties of samples subject to RRA treatment with water-quenching retrogression (ultimate tensile strength, yield strength, and elongation of 419.2 MPa, 370.2 MPa, and 15.9, respectively) are better than those of air-cooled and furnace-cooled samples. The corrosion resistance of water-quenching (IGC depth of 162.2 μm, corrosion current density of 0.833 × 10−5 A/cm2) and furnace-cooled samples (IGC depth of 123.7 μm, corrosion current density of 0.712 × 10−5 A/cm2) is better than that of air-cooled samples. Microstructure characterization reveals that the effect of the retrogression cooling rate on mechanical properties is related to the size of T'/η' precipitates with grains as well as the proportion of T' and η', while the difference in corrosion resistance depends on the continuity of grain boundary precipitates (GBPs). With mechanical properties, corrosion resistance, and time cost taken into consideration, it is appropriate to select water quenching for retrogression. These findings offer valuable insights for further design to achieve superior performance in various applications. [ABSTRACT FROM AUTHOR]

The traditional fabrication methods cannot design and fabricate the metal-bonded diamond tools with complex shape and porous structure, which hinders the heat conductivity and shape freedom. Additive manufacturing is considered as an emerging and potential process to form the metal-bonded diamond tools. In this paper, the influence of diamond content on the formability and mechanical properties of metal-bonded diamond tools fabricated by laser additive manufacturing process is investigated. Firstly, the manufacturing parameters of additively manufactured metal-bonded diamond tools with different diamond contents have been optimized based on the multiple parameters sintering experiment. Secondly, the influence of diamond content on the morphological and mechanical properties of metal-bonded diamond tools has been analyzed. Result indicates that the diamond abrasives are uniformly distributed and firmly embedded into the metal binder with chemical metallographic bonding, and the addition of diamond abrasives has changed the deformation behavior of the additively manufactured diamond tools. In detail, the increment of diamond content brings about the brittleness enhancement, ductility reduction, strength decline, and stiffness growth. [ABSTRACT FROM AUTHOR]

Highlights Characterized by rapid maturation, short growth cycles, and high strength and toughness, bamboo can be compounded with polymers to produce bamboofiber reinforced polymeric composites (BFRPCs). These composites exhibit corrosion resistance comparable to traditional materials such as glass fiber and carbon fiber composites. Additionally, they possess features like low density, high strength, degradability, and environmental friendliness, with low production costs and strong industrial applicability. This paper reviews the accomplishments in BFRPCs and provides an overview of the production processes for BFRPCs. Furthermore, it summarizes the research status of mechanical properties, moisture absorption characteristics, interface performance, and flame retardancy of these composites. The current issues with BFRPCs were analyzed. Finally, the paper explores future research directions and potential applications of BFRPCs. The performance studies on BFRPCs are comprehensively presented. Composite processing of BFPRCs is reviewed. Pros and cons of various types of BFRPCs are analyzed. Overview of the applications of BFRPCs in various domains is presented. Future trends and challenges of BFRPCs are introduced. [ABSTRACT FROM AUTHOR]