Search Results (752)

A comparative investigation of the corrosion behavior evolution of 15%SiCp/Al-Cu-Mg aluminum matrix composites (AMC) subjected to different heat treatments in a salt spray environment containing 5wt% NaCl was performed. Metallographic microscopy was used to observe the surface morphology of the corroded materials. Field-emission transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were used for microstructural evaluation and elemental analysis of the samples. Polarization curves and electrochemical impedance spectroscopy (EIS) were also employed to investigate the corrosion performance of the particle-reinforced aluminum matrix composites under different heat treatments. The test results indicate that, in addition to the influence of various grain boundary precipitates and electrochemical inhomogeneities between the precipitate-free zone (PFZ) and the aluminum matrix, differences in electrochemical properties between the SiC reinforcement particles and the aluminum alloy matrix are also a primary factor contributing to the corrosion of the aluminum-based composites in a 5wt% NaCl salt spray environment. Microstructural observations and electrochemical testing of AMC specimens at different corrosion stages indicate that under-aged samples exhibit relatively higher intergranular corrosion susceptibility. Under prolonged exposure to a salt spray environment, the over-aged specimen exhibited more pronounced galvanic corrosion phenomena, specifically, a significant decrease in Charge transfer resistance (R_ct) values and an increase in CPE values. R_ct results indicate that naturally aged AMC exhibits higher corrosion resistance than artificially aged AMC. With increased salt spray corrosion time, varying degrees of crevice corrosion occurred at the Al–SiC interface in all heat-treated samples. Full article

In this work, a composite solid polymer electrolyte was prepared for anodic bonding encapsulation. The effects of additives on the anodic bonding performance of the composites were investigated. Characterizations including AC impedance and X-ray diffraction show that CeO₂ and TiO₂ particles reduce the crystallinity of the (PEG)₁₂LiClO₄ matrix, thereby improving ionic conductivity and mechanical properties. The composite of (PEG)₁₂LiClO₄ with 5 wt.% CeO₂ and 5 wt.% TiO₂ achieves a room-temperature ionic conductivity of 1.01 × 10⁻⁵ S·cm⁻¹. Anodic bonding tests and interfacial characterization confirm its optimal bonding performance with aluminum. The interfacial tensile strength reaches 4.65 MPa at room temperature, and element migration is observed across the bonding interface. Full article

To overcome the low strength of conventional polytetrafluoroethylene/aluminum (PTFE/Al) reactive materials and the insufficient reaction efficiency of aluminum, this study introduces highly reactive aluminum–cerium alloys (Al-Ce-1#, -2#, and -3#, with Ce contents of 30, 50, and 70%, respectively; the primary phase in Al-Ce-3# is Al₂Ce) with a multiscale structural design (comprising both micron-sized and nano-sized particles) into an ammonium perchlorate (AP) matrix. Al/AP reactive materials and Al-Ce/AP reactive materials with varying Ce contents were prepared. The thermal decomposition characteristics, dynamic mechanical properties, and impact ignition behavior were systematically investigated using differential scanning calorimetry (DSC) and split Hopkinson pressure bar (SHPB) experiments. The results demonstrate that the addition of Al₂Ce significantly alters the thermal decomposition process of AP, substantially lowering its decomposition temperature (by approximately 69 °C) and promoting concentrated exothermic decomposition. SHPB tests reveal that Al₂Ce/AP composites exhibit higher dynamic yield strength and flow stress than the Al/AP, accumulating faster strain energy density under impact loading, which indicates a more violent fragmentation failure mode. This enhanced mechanical failure behavior, which provides highly reactive interfaces and promotes hotspot formation, synergizes with the catalytic effect of Al₂Ce on AP decomposition. Together, these mechanisms jointly improve the impact ignition sensitivity of the material, significantly lowering its ignition threshold and shortening its combustion duration. This study confirms that Al₂Ce/AP is a novel reactive material combining excellent dynamic mechanical properties with outstanding impact reactivity, providing theoretical and technical support for the application of highly reactive rare-earth aluminum alloys in aluminum-based reactive materials. Full article

To enable non-destructive quantitative characterization of constituent content in C/C–SiC ceramic-matrix composites, this study develops a physics-guided framework based on multispectral photon-counting X-ray detection. In practical photon-counting measurements, multispectral attenuation features are jointly distorted by detector-response non-idealities, including charge sharing, K-escape, and finite energy resolution, as well as by beam-hardening effects from the polychromatic X-ray source. To address this coupled problem, a Geant4 11.2-based detector-response model was incorporated into a unified correction workflow together with beam-hardening compensation, so that physically consistent multispectral attenuation vectors could be recovered for subsequent constituent inversion rather than merely for spectrum restoration. On this basis, a fine-grained theoretical database covering different SiC mass fractions was established, and quantitative constituent inversion was achieved by matching the corrected attenuation features to the database. Experimental results show that the proposed framework effectively suppresses thickness-dependent bias in attenuation measurements and yields an average relative error below 3% for pure aluminum. For C/C–SiC composites, the SiC mass fraction can be quantified with an accuracy better than 3 wt%. These results demonstrate that the proposed method provides a practical non-destructive route for constituent-content characterization in heterogeneous ceramic-matrix composites and is valuable for manufacturing quality control and in-service assessment. Full article

Aluminum–graphene nanoplatelet (Al/GNP) composites have attracted significant attention as lightweight structural materials, yet their mechanical performance is strongly influenced by interfacial reactions and the formation of carbides. In this study, Al/GNP composites containing 0.1–1.1 wt.% graphene were produced via powder metallurgy and hot extrusion at 400 °C and 500 °C. Hot extrusion at the higher temperature enables the controlled in situ formation of aluminum carbide (Al₄C₃). A comprehensive microstructural characterization using SEM and HRTEM was combined with tensile testing to elucidate the influence of carbide size on mechanical behavior. Hot extrusion at 500 °C promotes the formation of uniformly distributed, nanoscale Al₄C₃ carbides whose size, morphology, and aspect ratio depend on graphene content. Composites containing nano-sized carbides exhibit a markedly improved strength–ductility balance compared to carbide-free counterparts, with optimal performance achieved at 0.3 and 0.7 wt.% GNPs. The enhancement is attributed to synergistic strengthening mechanisms involving improved interfacial bonding, efficient load transfer, nanoscale dispersion strengthening, and carbide–dislocation interactions. The results indicate that the controlled formation of nanoscale Al₄C₃ is not detrimental; rather, it contributes to the optimization of the mechanical properties of Al/GNP composites. Unlike most previous studies that treat carbide formation as a detrimental effect, this work demonstrates that its controlled nanoscale evolution can be used as a deliberate strengthening strategy through its influence on microstructural mechanisms. Full article

Calcium–silicate–hydrate (C-S-H), the primary binding phase governing cement paste cohesion, undergoes progressive physicochemical transformation upon carbonation—a process that critically dictates concrete durability in atmospheric environments. When CO₂ penetrates the porous cement matrix, it triggers a cascade of degradation mechanisms: calcium leaching decalcifies the C-S-H structure, inducing polymerization of silicate chains from dimeric to longer-chain configurations, while concurrent precipitation of calcium carbonate and amorphous silica gel fundamentally reconstitutes the nanoscale architecture. These nanoscale alterations propagate to macroscopic property evolution, manifesting as initial strength and stiffness gains due to pore-filling carbonation products followed by eventual deterioration as the cohesive binding network deteriorates. This review synthesizes current understanding of carbonation-induced structural evolution, examining the coupled influences of environmental parameters—CO₂ concentration, relative humidity, and temperature—alongside C-S-H intrinsic chemistry (Ca/Si ratio, aluminum substitution, and alkali content) on reaction kinetics and material performance. However, significant knowledge gaps persist: predictive models for in-service carbonation rates remain elusive due to the disconnect between idealized laboratory conditions and the heterogeneous, cracked reality of field concrete; the causal linkage between nanoscale C-S-H alteration and macroscale cracking patterns along with physical performance is poorly resolved, and most mechanistic studies rely on synthetic C-S-H, neglecting the compositional complexity of real Portland cement systems. We further propose emerging protection strategies, including surface barrier coatings and low-carbon alternative binders (geopolymers, calcium sulfoaluminate cements, carbon-negative materials such as recycled cement), which demonstrate enhanced carbonation resistance. Future research priorities include developing effective coating barriers for carbonation protection, developing operando characterization techniques for real-time reaction monitoring, deploying machine learning algorithms to bridge atomistic simulations with structural-scale predictions, and establishing long-term field performance databases to validate laboratory-derived degradation models. Full article

Cadmium contamination of water resources represents a serious environmental and public health challenge, with conventional treatment methods often proving inadequate for industrial-level remediation. In this study, we present a novel, sustainable composite material, functionalized cellulose nanocrystal polyvinyl alcohol zinc oxide ferric chloride (CNC-PVA-ZnOFe) beads for the efficient removal of cadmium from contaminated water. The material integrates adsorption, coagulation, and flocculation mechanisms within a single hybrid platform, with coagulation–flocculation serving as the dominant mechanism given the material’s macroporous structure and limited surface area (1.2–3.3 m²/g). Functionalized cellulose nanocrystals provide supporting adsorptive sites for metal binding, while a PVA matrix incorporating ZnOFe improves structural integrity, mechanical stability, and coagulation performance. Characterization confirmed successful functionalization, enhanced thermal stability, and a macroporous structure (12–52 nm pores) conducive to floc entrapment, though with limited surface area (1.2–3.3 m²/g) for conventional adsorption. Under optimized conditions (pH 7–10, initial Cd²⁺ concentration of 100 mg/L, coagulant dose of 0.1 g, and sedimentation time of 60 min), the functionalized CNC-PVA-ZnOFe beads achieved a cadmium removal efficiency of 78%, achieving significantly higher cadmium removal efficiency than traditional coagulants, such as aluminum sulfate (69%). The beads also demonstrated good reusability, retaining 85% removal efficiency after five regeneration cycles. This work presents a scalable, eco-friendly material for cadmium removal under controlled laboratory conditions using synthetic solutions. However, further evaluation in real wastewater matrices containing competing ions and organic matter is necessary to establish practical applicability for water treatment applications. The study highlights the combined potential of multifunctional hybrid materials while acknowledging the need for validation under environmentally relevant conditions. While the results indicate successful integration of multiple removal mechanisms, direct validation of synergistic interactions through techniques such as zeta potential and XPS analysis remains an important direction for future research. Full article

Particle-reinforced aluminum matrix composite (AMC)/steel hybrid structures present considerable benefits for lightweight design and enhanced product performance. This article provides a systematic overview of research advances from 2003 to 2024 on laser welding of particle-reinforced AMCs to steel, with particular emphasis on the influence of laser welding parameters, shielding gas, and reinforcing particles on the mechanical properties of the welded joints. The mechanisms by which intermetallic compounds (IMCs) impair joint strength are thoroughly analyzed. Moreover, the effects of rare earth element additions on both mechanical properties and corrosion resistance of the joints are critically assessed, along with the coupling mechanism between rare earth elements and the reinforcement phase. Key insights from the literature reveal that regulating heat input can effectively suppress harmful interfacial reactions. Meanwhile, the synergistic incorporation of rare earth elements not only refines the grain structure and boosts mechanical strength, but also improves corrosion resistance through the formation of dense surface oxide films and grain boundary strengthening. This review underscores the innovative integration of interfacial reaction control with rare earth microalloying to achieve high-performance AMC/steel laser-welded joints—a distinct departure from prior studies that typically investigated these strategies separately. Full article

Metal packaging materials remain fundamental across food, beverage, pharmaceutical, cosmetic, and technical sectors owing to their combination of mechanical robustness, total light and gas barrier performance, thermal resistance, and established recyclability. Aluminum alloys, tinplate, tin-free steel (TFS/ECCS), stainless steels, metal–matrix composites (MMCs), and metal–polymer or metal–paper laminates define distinct metal-based packaging architectures whose metallurgical and interfacial design governs forming behaviour, corrosion and migration pathways, coating integrity, and mechanical reliability. In this review, these architectures are examined from a materials- and systems-oriented perspective, linking composition, microstructure, processing routes, and surface engineering to functional performance across rigid, semi-rigid, and flexible formats. The analysis also considers the ongoing transition from bisphenol A (BPA)-based epoxy linings to BPA-free and hybrid coating chemistries, the use of nano-structured metallic and metal-oxide surfaces, and the role of composite laminates in which thin metallic foils are combined with polymeric or paper-based structural layers. These material and architectural aspects are discussed together with safety, regulatory, and circularity considerations that increasingly influence the design and selection of metal-based packaging. Ion migration, coating degradation, and corrosion under realistic storage environments are considered in relation to EU, FDA, ISO, and sector-specific requirements, while attention is also paid to the contrast between well-established closed-loop recycling infrastructures for aluminum and steel and the more complex end-of-life management of coated metals and multilayer laminates. The review provides a unified framework connecting materials selection, metallurgical design, processing, performance, regulatory compliance, and sustainability in metal-based packaging systems. Applications spanning consumer goods, pharmaceuticals, cosmetics, and advanced electronics are integrated to support an overall understanding of how metallic and hybrid metal-based architectures underpin functional reliability and life-cycle sustainability. Full article

Friction stir-welding (FSW) is widely recognized as a modern solid-state technology used to join dissimilar materials by solid-state mechanical mixing. Such mechanical mixing can be exploited to fabricate in situ composite structures through solid-state deformation mechanisms. The present investigation highlights the microstructural evolution and mechanical properties of an in situ composite structure fabricated by FSW of aluminum (Al) to titanium (Ti) incorporating a thin Nickel (Ni) interlayer. A 0.1 mm thick Ni foil was placed across the full butt interface between 4 mm thick Al and Ti plates before friction stir-welding. Properties of the composite were investigated in detail, and the results revealed that fragmented Ti and Ni particles of different sizes were consolidated in the weld nugget. Al, on the other hand, exhibited substantial microstructural refinement and developed an equiaxed microstructure with random grain orientation, mixed grain boundaries and low micro-strain accumulation in the weld nugget. At the processing temperature, Al reacted with both Ti and Ni to form multiple intermetallic compounds. Tensile testing indicated that the tensile properties of the weld were close to those of the base aluminum. This retention of mechanical properties in spite of recrystallization is attributed to the following mechanisms: (1) Ti and Ni undergo severe deformation, forming fine particles with varying sizes and shapes; (2) at particle interfaces, diffusion and chemical reactions produce interlayers and intermetallic compounds; (3) these particles are consolidated within dynamically recrystallized Al, imparting composite characteristics to the weld nugget; and (4) the particles containing intermetallic compounds act as dispersoids in the Al matrix. Quantitatively, the weld retained 98% (104.2 ± 3.3 MPa) UTS and 90% (17.1 ± 1.2) ductility of base aluminum, demonstrating the effectiveness of the Ni interlayer approach in controlling brittle intermetallic formation. Full article

A composite meeting the UL94 V-0 rating was produced by adding 30 wt% epoxy silane-modified aluminum trihydrate (EPATH) to a 60/40 epoxy/benzoxazine matrix. Various bimodal and trimodal composites containing 20–40 wt% of three types of ceramic fillers, i.e., aluminum oxide (Al₂O₃), boron nitride (BN), and magnesium oxide (MgO), were prepared to simultaneously achieve flame-retardant and thermal conductive properties. The bimodal composites with 40 wt% of Al₂O₃ and MgO exhibited thermal conductivities of 1.22 W/m∙K and 1.29 W/m∙K, respectively, which were superior to that of the composite containing the same amount of ATH (1.0 W/m∙K). In contrast, both the coefficient of thermal expansion (CTE) and shear strength decreased with increasing ceramic filler content. For agglomerated BN, the filler loading was constrained above 30 wt% because its high specific volume caused a significant rise in the viscosity. In the trimodal composites with a total filler content of 40 wt% of Al₂O₃ and BN, a BN fraction of 7.5 wt% yielded the highest thermal conductivity of 1.64 W/m∙K and the lowest water absorption of 0.69%. When the trimodal composites were exposed to −55 °C and 150 °C for 1000 h, they exhibited a reduction in shear strength of less than 30% compared to their initial values. Full article

In critical sectors such as energy, transportation, and high-end manufacturing, components must endure simultaneous exposure to high temperatures, heavy loads, and severe wear, necessitating materials with balanced strength, toughness, and durability. Metal matrix composites (MMCs), enhanced with ceramic reinforcements, offer a promising solution to these multifaceted demands. While conventional techniques like casting and powder metallurgy often struggle with limited design freedom and uniform reinforcement distribution, additive manufacturing (AM) enables the production of complex, graded components with tailored microstructures and unlocks new possibilities for materials operating under extreme service conditions. This review systematically examines recent advances in AM-processed MMCs—focusing on aluminum-, titanium-, nickel-, and steel-based systems—for applications in coupled extreme environments. It provides a detailed analysis of their high-temperature mechanical performance and wear resistance, emphasizing the roles of reinforcement selection, microstructural design, and AM processing parameters in governing key properties. Furthermore, the underlying strengthening and wear mechanisms are discussed, along with current challenges and future opportunities. This work aims to serve as a foundational reference for the development of next-generation AM MMCs tailored for high-performance engineering applications. Full article

Scandium (Sc), when added together with magnesium (Mg), forms a highly effective synergistic pair in aluminum (Al) alloys, enhancing their performance in various applications. While the thermomechanical processing and heat treatment of such Al-Mg-Sc alloys have been well investigated, the behavior and features of their as-cast state remain less understood. In particular, the evolution of cellular/dendritic microstructures and the formation of phases at submicrometric and nanometric scales, especially those developing during solid-state cooling, require further elucidation. The present study employs a combination of conventional and advanced characterization techniques in the Al-5 wt.%Mg-0.4 wt.% Sc alloy, including CALPHAD, optical microscopy, scanning electron microscopy (SEM), transmission and scanning transmission electron microscopy (TEM/STEM) with energy-dispersive spectroscopy (EDS), x-ray diffractometry (XRD), tensile testing, and fractographic analysis. Al-rich dendrites surrounded by Al₃Sc, AlFe, and β-Al₃Mg₂ phases and the formation of primary submicrometric clusters containing AlFe and Al₃Sc have been identified, revealing important microstructural features that depend strongly on the solidification conditions. Moreover, nanometric Al₃Sc precipitates mainly in the form of rod-like structures with sizes in the order of 50–200 nm have been observed within the α-Al matrix during solid-state cooling stage. At higher solidification rates, such as 15.3 °C/s, these precipitates remain predominantly in solid solution, indicating strong solidification rate dependence in the precipitation behavior. Comparisons between alloys containing 0.1 Sc and 0.4 Sc have demonstrated that the morphology, size, and distribution of Sc-rich phases significantly affect the stress–strain tensile response and underlying strengthening mechanisms. Distinct Portevin–Le Chatelier (PLC) effects have been observed, corresponding to very different serration activities in the stress–strain curves comparing both Al-5%Mg-0.4%Sc and Al-5%Mg-0.1%Sc alloy samples. Among the compositions and conditions studied, the Al–5Mg–0.4Sc alloy samples solidified under the fast-cooling condition (11.2 °C/s) exhibited the most improved mechanical performance, attaining a strength of 306 MPa and an elongation of 22.6%, underscoring the pivotal role of Sc content and solidification rate in achieving optimized mechanical properties. Full article

Metal matrix composites (MMCs) are one of the significant engineering materials for many industrial applications. The growing interest in MMCs stems from their strong mechanical properties, including their higher specific mechanical strength and excellent corrosion and wear resistance. From an industrial viewpoint, the ability of MMCs to undergo secondary processing is significant. This review aims to clarify the effects of cryorolling on the microstructure, mechanical properties and wear behavior of different aluminum-based MMCs. In particular, aluminum matrix composites (AMCs) produced through the stir-casting approach experience an additional cryorolling procedure to enhance their tensile mechanical strength and wear resistance. This hybrid manufacturing approach has shown promise in creating effective structural components. This review covers the production of ex situ aluminum-based composites formed by stir casting and then cryorolling. It also highlights how the particle size, volume fraction, and the cryorolling procedure affect the microstructure, wear, and mechanical properties. This approach could broaden the uses of hybrid manufacturing by demonstrating its practical advantages and efficiency. Furthermore, this review highlights the importance of implementing machine learning (ML) models and life cycle assessment (LCA) in evaluating MMCs produced through stir casting. Full article

The influence of electron beam treatment parameters (electron gun speed, electron beam current, scanning frequency, and sweep type) on the structure and properties of the surface layer of the composite material AlMg3-5SiC has been investigated. Composite specimens of AlMg₃ alloy reinforced with 5 wt.% silicon carbide particles were manufactured via the stir casting process. Experimentally, processing modes with heat input from 120 to 240 J/mm yield a modified layer thickness from 74 to 1705 µm. Heat input should not exceed 150 J/mm to ensure a smooth and defect-free surface layer. The macro- and microstructure were examined using optical microscopy. Brinell hardness was measured. Friction and wear tests were performed under dry sliding friction conditions using the “bushing on plate” scheme. This evaluated the tribological properties of the composite material in its original cast state and after modifying treatment. Due to the matrix alloy structure refinement by 5–10 times, the surface layer’s hardness increases by 11% after treatment. The modified specimens have superior tribological properties to the initial ones. Wear rate reduces by 17.5%, the average friction coefficient reduces by 32%, and the root mean squared error of the friction coefficient, which measures friction process stability, reduces by 50% at a specific load of 2.5 MPa. Therefore, the electron beam treatment process is a useful method for producing high-quality and uniform wear-resistant aluminum matrix composite surface layers. Full article