This study investigates the influence of nano-sized reinforcements on aluminum matrix composites’ mechanical and tribological properties. Microstructural analysis revealed that introducing nanoparticles led to grain refinement, reducing the grain size from 129.7 μm to 41.3 μm with 2 wt.% TiO₂ addition. Furthermore, ultrasonic-assisted squeeze casting of AA6061 composites reinforced with TiO₂ and Al₂O₃ resulted in a 52% decrease in grain size, demonstrating nano-reinforcements’ effectiveness in refining the matrix structure. Despite these advantages, the high surface energy of nanoparticles causes agglomeration, which can undermine composite performance. However, ultrasonic-assisted stir casting reduced agglomeration by approximately 80% compared to conventional stir casting, and cold isostatic pressing improved dispersion uniformity by 27%. The incorporation of nano-reinforcements such as SiC, Al₂O₃, and TiC significantly enhanced the material properties, with hardness increasing by ~30% and ultimate tensile strength improving by ~80% compared to pure Al. The hardness of nano-reinforced composites substantially rose from 83 HV (pure Al) to 117 HV with 1.0 vol.% CNT reinforcement. Additionally, TiC-reinforced AA7075 composites improved hardness from 94.41 HB to 277.55 HB after 10 h of milling, indicating a nearly threefold increase. The wear resistance of Al-Si alloys was notably improved, with wear rates reduced by up to 52%, while the coefficient of friction decreased by 20–40% with the incorporation of graphene and CNT reinforcements. These findings highlight the potential of nano-reinforcements in significantly improving the mechanical and tribological performance of n-AMCs, making them suitable for high-performance applications in aerospace, automotive, and structural industries.

Natural fiber‐reinforced polymeric composites (NFRCs) offer a sustainable solution at the intersection of environmental consciousness and materials engineering. These composites address plastic pollution and industrial material demands by utilizing natural fibers with the advantages of biodegradability, lightweight properties, economic viability, and promising mechanical characteristics. Technical challenges remain, including inconsistent fiber quality, inadequate mechanical stability, water absorption, thermal instability, and compatibility issues with hydrophobic matrices. This work examines bamboo, flax, and hemp fibers and their integration into polymer composites, analyzing various surface modification techniques and their impact on mechanical performance and fiber‐matrix interactions. Our investigation covers fundamental fiber properties, advanced surface treatments, resultant effects in polymer composites, and commercial applications across diverse industries. Environmental impact is evaluated through detailed life cycle assessments, focusing on automotive applications where NFRCs show particular promise for lightweight component manufacturing. The work concludes with a future outlook identifying emerging trends and research opportunities, providing researchers, engineers, and industry practitioners with a strategic roadmap for advancing NFRC technology as part of the broader transition toward sustainable materials engineering solutions.Highlights: NFRCs offer sustainable options with promising mechanical performance. Challenges: inconsistent fiber quality, water absorption, matrix compatibility. Analysis of bamboo, flax, hemp: surface modifications, mechanical performance. LCA highlights NFRC's role in lightweight, sustainable manufacturing. Review offers a strategic roadmap to advance natural fiber composite materials.

Bio-based materials are becoming pivotal in creating a more sustainable future by mitigating the adverse effects of climate change, primarily motivated by fossil fuel consumption. Among these materials, natural fiber composites have seen a resurgence over the past two decades due to the demand for environmentally friendly alternatives that offer biodegradability and recyclability. These composites are widely used in industries such as automotive, packaging, sports, construction, and consumer products. Hemp fiber, in particular, is valued for its exceptional mechanical properties, including strength and stiffness comparable to glass fibers. This review consolidates research on hemp fiber–reinforced bio-composites, focusing on their structural characteristics, and performance enhancement techniques. Both chemical and physical modification strategies are employed to optimize fiber properties and improve compatibility with polymer matrices. Chemical methods involve using reagents to reduce fiber hydrophilicity, enhancing compatibility and coupling efficiency. Physical methods adjust fiber structure and surface properties to improve interfacial bonding, offering cleaner solutions. The paper examines recent advancements in these methods and discusses the mechanical properties of hemp fiber–reinforced bio-composites. It concludes with reflections on the future prospects for hemp fiber–reinforced polymer bio-composites.

Al-Si alloys are vital in the aerospace and automotive industries due to their high strength-to-weight ratio, excellent ductility, and superior corrosion resistance. These properties, along with good thermal conductivity, low thermal expansion, and enhanced wear resistance due to silicon, make them ideal for lightweight, high-performance components like engine parts exposed to harsh conditions and thermal cycling. In recent years, the development of aluminium metal matrix composites using Al-Si alloys as the base material has gathered significant attention. These composites are engineered by integrating various reinforcing particles into the aluminium matrix, which results in remarkable improvements in the wear resistance, hardness, and overall mechanical performance of the material. The stir casting process, a well-established and cost-effective method, is frequently employed to ensure a uniform distribution of these reinforcing particles within the matrix. This review delves into the influence of different types of reinforcing particles on the properties of Al-Si alloy-based AMCs. The incorporation of these reinforcements has been shown to significantly enhance wear resistance, reduce friction, and improve the overall strength and toughness of the composites, making them ideal candidates for high-performance applications in the automotive and aerospace sectors. Moreover, this review highlights the challenges associated with the fabrication of these composites, such as achieving a homogeneous particle distribution and minimizing porosity. It also discusses the latest advancements in processing techniques aimed at overcoming these challenges. Additionally, this review addresses the potential environmental and economic benefits of using natural reinforcements, which not only reduce material costs but also contribute to sustainable manufacturing practices.

This review provides a comprehensive exploration of the current research landscape surrounding nanoclay-reinforced epoxy composites. A primary challenge in developing these nanocomposites is the hydrophilic nature of pristine clay, which hinders its dispersion within the epoxy matrix. To address this issue, organic modifiers are frequently employed to enhance clay compatibility and facilitate effective incorporation into the nanocomposite structure. The unique properties of nanoclay make it a particularly attractive reinforcement material. The performance of nanoclay/epoxy nanocomposites is largely determined by their morphology, which is influenced by various factors including processing methods, clay types, modifiers, and curing agents. A thorough understanding and control of these parameters are essential for optimizing nanocomposite performance. These advanced materials find extensive applications across multiple industries, including aerospace, defense, anti-corrosive coatings, automotive, and packaging. This review offers an in-depth analysis of the processing techniques, mechanical properties, barrier capabilities, and thermal characteristics of nanoclay-reinforced epoxy nanocomposites. Additionally, it explores their diverse industrial applications, providing a holistic view of their potential and current use. By examining the multifaceted landscape of epoxy/clay nanocomposites, this review illuminates the intricate relationships between fabrication methods, resulting properties, and potential industrial applications. It serves as a comprehensive resource for researchers and practitioners seeking to advance the development and application of these innovative materials.