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.

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.

In this work, high-temperature tribological characteristics of ilmenite-reinforced LM13 aluminum alloy–based matrix composites (AMCs) and boron carbide–reinforced AMCs are compared. Stir-cast composites were processed using boron carbide (covalently bonded discontinuous particles (CDP)) and ilmenite (natural discontinuous particles (NDP)) particles separately as reinforcements. The particle size range was 106–125 µm, and reinforcement levels were 5, 10, and 15 wt% for both types of composites. Both composites exhibited a uniform distribution of reinforced particles and grain refinement. Compared to the LM13 base alloy, NDP composite containing 15 wt% reinforcement showed significant improvement in hardness (57%), coefficient of friction (57%), mild-to-severe wear transition temperature, average steady-state wear-rate (49%), and coefficient of thermal expansion (55%). CDP-15 composite showed slightly better properties than NDP-15 composite. Microstructure refinement, increased dimensional stability, formation of the oxide layer, and formation of tribolayer due to reinforcement of the ceramic fillers were the main reasons for the improvement in properties of processed AMCs. Scanning electron microscope (SEM)-energy dispersive spectroscopy (EDS) of wear tracks-debris showed abrasive/delamination wear as the main mechanism for materials loss. The research showed that the low-cost ilmenite particles can substitute for the very costly boron carbide particles as reinforcements in AMCs used for dry sliding wear applications under high operating temperatures–applied load conditions of the order of 300 °C–49 N.

The primary focus of this study is the application of friction stir processing to produce surface composites of in situ AA5083-H111/Al–Fe. These composites were fabricated by mixing mechanically alloyed Fe–40 wt% Al powder for 40 h. The AA5083 substrate underwent a two-pass friction stir processing with changes in the tool’s movement direction during fabrication. This experiment used Taguchi’s L9 orthogonal array design to gather and analyse data efficiently. Following each friction stir processing pass, the fabricated aluminium metal matrix composite microstructure, hardness and ultimate tensile strength were conducted. In this study, the maximum tensile strength of 225.8 MPa after the first pass and 253.6 MPa after the second pass. Additionally, microhardness measurements indicated values of 123.3 and 128.3 Hv after the first and second passes, respectively. These impressive mechanical properties were achieved by optimizing specific process parameters, including a tool shoulder diameter of 21 mm, a tool rotational speed of 900 rpm, a tool traverse speed of 63 mm/min and a tilt angle of 1.5°. Furthermore, examining the fracture surface of the friction stir processed sample revealed ductile failure behaviour, suggesting that the material experienced deformation and stretching before fracture. This observation aligns with the inherent ductile nature of the AA5083/Al–Fe composite.