To achieve the synergistic optimization of flexural strength and thermal expansion coefficient (TEC) in ceramic composites, a coupled predictive model based on Eshelby’s equivalent inclusion theory and Mori–Tanaka homogenization theory is established for two-phase composites. The flexural strength model incorporates matrix damage, interfacial debonding, and particle fracture, while the TEC model further considers the interfacial phase. Si3N4/MAS (Cordierite) composites with different MAS contents are fabricated by vacuum hot-press sintering for validation. The effects of MAS content on the phase composition, microstructure, relative density, and mechanical properties of the composites are investigated. The results show that the model predicts an optimal MAS content range of 18.5–24.5 vol.% under the dual requirements of high strength and low TEC. The optimal comprehensive performance is achieved at 20 vol.% MAS. For this composition, the relative density, Vickers hardness, fracture toughness, and flexural strength reach 99.03 ± 0.12 %, 14.99 ± 0.08 GPa, 6.03 ± 0.16 MPa·m1/2, and 493.67 ± 47.62 MPa, respectively. XRD and SEM analyses indicate that appropriate MAS addition promotes α→β phase transformation, densification, and the formation of elongated β-Si3N4 grains. The enhanced properties are mainly attributed to residual compressive stresses induced by thermal expansion mismatch, together with crack deflection, interfacial debonding, grain bridging, and grain pull-out mechanisms. The proposed model provides theoretical guidance for the design of ceramic composites with high strength and low TEC.
Sandwich structures are extensively used in lightweight structural applications due to their efficient load carrying capability and low mass. While metallic and thermoset composite skins have been widely investigated, long fiber thermoplastics (LFTs) as sandwich face sheets still lack a comprehensive and structure oriented critical review. This paper provides a targeted critical review of sandwich structures with a specific focus on LFT skins, addressing their mechanical behavior under quasi-static and impact loading conditions. Dominant damage and failure mechanisms including core crushing, face-core debonding, delamination, and face-sheet fracture are examined, and the role of key LFT design parameters, such as fiber length, fiber orientation, matrix system, manufacturing route, and joining method, is critically assessed in terms of stiffness, energy absorption, and residual structural performance. The review indicates that LFT skins offer a balanced combination of mechanical performance, damage tolerance, manufacturability, and sustainability, supporting their potential as face-sheet materials for selected sandwich applications. Remaining challenges and research gaps, particularly related to temperature-dependent behavior, interfacial durability, and cross-study comparison metrics, are identified, and future research directions are proposed.
Densifying active functional groups on graphene oxide (GO) is key to its covalent functionalization toward high-performance GO/polymer composites. Inspired by the “anchor-first, then spread” wall-climbing mechanism of Boston ivy, this study proposes a “point-to-line” strategy to densify active sites on GO. First, holey GO (HGO) with well-distributed nanopores at the basal plane is prepared by chemically etching GO, which is further oxidized and grafted with ethylenediamine to yield amino-terminated HGO containing rich amino groups at both the edge and basal plane. Then, poly(acrylic acid) (PAA, like vine) “climbs” onto HGO (as the wall) by the amino group “feet” via amidation reaction, obtaining PAA-HGO with denser carboxy groups. Finally, PAA-HGO/polyamide 56 (PA56) fibers are prepared by in situ polymerization and melt spinning. The 0.2%PAA-HGO/PA56 fiber exhibits 1358 MPa tensile strength and 3.0 GPa Young’s modulus, which are 3.2 and 2.5 times those of neat PA56 fiber, respectively. Its tensile toughness reaches 452 MJ·m–3. The improvement arises because dense carboxyl groups on PAA-HGO form numerous interfacial amide bonds, thereby enhancing load transfer, together with increased crystallinity and crystallite orientation. Furthermore, 1%PAA-HGO/PA56 composite is used as a masterbatch and melt-blended with commercial PA56 (C-PA56). The 0.2%PAA-HGO/PA56/C-PA56 fiber exhibits 1647 MPa tensile strength (record value for nylon-based fibers) and 3.0 GPa Young’s modulus, which are 3.0 and 1.7 times those of C-PA56 fiber, respectively. Its tensile toughness reaches 593 MJ·m–3. Further strengthening is partly attributed to the increase in the overall molecular weight. This strategy enables ultra-strong yet tough polymer composites.
Metal Matrix Composites (MMCs) are advanced materials known for their high specific strength, stiffness, wear resistance, and thermal stability, making them vital for aerospace, automotive, defence, and energy sectors. However, traditional trial-and-error approaches for their design and development are inefficient, costly, and inadequate for exploring complex compositional and processing spaces. Recent advancements in Artificial Intelligence (AI) and Machine Learning (ML) have enabled a shift toward data-driven and predictive frameworks in MMC development. This review highlights AI/ML applications across the MMCs lifecycle, including materials design, processing, and characterization. It discusses the use of supervised, unsupervised, and reinforcement learning models to optimize matrix–reinforcement combinations, volume fractions, particle morphology, and interfacial properties. The integration of physics-informed and hybrid models for capturing complex strengthening mechanisms and interfacial phenomena is also examined. Further, the review explores ML-driven approaches for real-time process monitoring, defect prediction, microstructure control, and parameter optimization. In characterization, AI techniques are increasingly used for automated microstructure analysis, phase identification, damage detection, and property prediction. Emerging trends such as multimodal data fusion, explainable AI, uncertainty quantification, and the development of open-access materials databases are also discussed. The review concludes by identifying key challenges, including the need for high-quality datasets, standardized methodologies, and better integration of domain knowledge, to enable sustainable and accelerated development of next-generation MMCs.
The increasing demand for lightweight and high-performance materials in the sustainable energy generation has led to the widespread adoption of carbon fiber reinforced thermoplastic (CFRTP) composites. This research focused on the application of the verified vibrational method to evaluate the residual modulus distribution of CFRTP sandwich structures subjected to hydrothermal aging in freshwater and seawater environments. Sandwich composites with unidirectional skins and carbon fiber paper-reinforced Polyamide 6 cores were fabricated and exposed to accelerated aging conditions. The effects of aging on the internal microstructure, physical properties, mechanical performance, and failure modes were systematically investigated. X-ray micro-computed tomography was utilized to analyze the internal geometry and fiber orientation distribution of specimens before and after aging. The residual modulus distribution of the aged sandwich composites was determined using the non-destructive vibrational method, with an average error reaching as low as 3.98%, demonstrating the preliminary applicability of this method. The findings of this research have implications for the safe and efficient use of CFRTP composites in sustainable energy applications.
This study investigated the effects of cold rolling on the microstructure, seawater corrosion, and microbiologically influenced corrosion (MIC) behavior of wire-arc additive manufactured (WAAM) Cu-4.2Sn/steel composites. A cumulative rolling reduction of 10% decreased the average grain size of the Cu-4.2Sn layer from 63.2 ± 4.6 μm to 42.5 ± 3.8 μm, increased the fraction of low-angle grain boundaries from 6.2% to 9.6%, introduced Σ3 twin boundaries accounting for 13.42% of the total grain-boundary length, and fragmented the Cu6Sn5 phase into finer particles. The rolled alloy exhibited a lower initial Rct (1.58 × 103 Ω·cm2) than the WAAM alloy (2.31 × 103 Ω·cm2), consistent with the increased density of deformation-induced interfaces and locally active sites. During prolonged immersion, however, the rolled alloy developed a thicker corrosion product film (6.22 ± 0.17 μm versus 5.11 ± 0.25 μm for the WAAM alloy) and a higher critical scratch load for film detachment (18.8 versus 15.1 mN). Its maximum Rct reached 1.65 × 104 Ω·cm2, compared with 1.30 × 104 Ω·cm2 for the WAAM condition. In P. aeruginosa-containing medium, both alloys exhibited an initial increase followed by a decrease in corrosion resistance. After 30 d, the rolled alloy retained a higher Rct of 7.95 × 103 Ω·cm2 than the WAAM alloy (4.71 × 103 Ω·cm2).
This study presents an experimental and numerical investigation of a brake friction composite reinforced with basalt fiber and platelet potassium-magnesium titanate. The proportions of the two reinforcements were optimized through mechanical and friction-wear testing, and the resulting composite was characterized for friction stability and fade resistance over a wide temperature range. Finite element simulations using Abaqus established a thermal-mechanical coupled model simulating emergency braking and prolonged continuous braking. The simulated temperature and stress fields were correlated with experimental worn surface morphologies and friction coefficient evolution. Results show that the combination of basalt fiber and platelet potassium-magnesium titanate enhances friction stability, wear resistance, and fade resistance. The finite element analysis further reveals favorable heat dissipation and uniform contact stress distribution under extreme braking. This integrated approach numerically evaluates the feasibility of applying this composite under demanding braking conditions and provides mechanistic insights for the design of high-performance brake friction materials.
Icing on fiber-reinforced composites poses a critical challenge in cold environments, leading to performance degradation and reduced operational reliability. To address this problem, approaches involving metallic wire stitching and microwave-assisted heating are investigated as a material-level deicing strategy. An optimal stitching geometry for concentrated electromagnetic wave absorption was initially designed using COMSOL Multiphysics simulations. The preliminary stitching design was experimentally validated using a microwave antenna system. The glass fiber-reinforced plastic (GFRP) specimen with a stitching length of 3 cm reached 74.8°C within 300 s under 20 W of microwave heating. For the 1-line stitched GFRP, localized ice removal along the SUS/aramid stitching path was achieved within 15 min, followed by complete deicing within 30 min. The 8-line stitched GFRP further reduced the complete deicing time to 25 min. The 1-line stitched GFRP exhibited improved flexural properties while maintaining tensile performance. After deicing, the stitched GFRP retained 91.0% of its original flexural strength, while the flexural modulus was nearly unchanged. Under low-velocity impact (15 J), the impact energy absorption increased slightly, consistent with a comparable impact response after repeated deicing. This research provides material-level insights into microwave-assisted deicing of composite structures.
