A REVIEW ON THERMAL PROPERTIES OF METALMATRIX COMPOSITES

Engineering

The Metal Matrix Composites (MMCs) represent an exceptional class of engineered materials where metallic matrices are harmoniously combined with various reinforcements such as ceramics, carbon fibers, and whiskers to achieve a formidable blend of enhanced mechanical properties, wear resistance, and, notably, sophisticated thermal performance. These composites stand at the forefront of modern engineering, especially in sectors like aerospace, automotive, electronics, and energy, where heat dissipation and material stability under thermal stress are paramount. The thermal behavior of MMCs—comprising their thermal conductivity, expansion, heat storage capabilities, stability under heat, and resistance to thermal fatigue—plays an indispensable role in defining the material’s operational efficacy in demanding environments. At the heart of MMCs’ thermal conductivity lies a delicate balance between the heat-conducting matrix material and the low-conductivity reinforcements. While the metal matrix (often aluminum, copper, or titanium) provides the high thermal conductivity necessary for rapid heat dissipation, the inclusion of ceramic reinforcements, such as silicon carbide (SiC) or alumina (Al₂O₃), effectively reduces this conductivity, as these materials are known for their insulating characteristics. The resulting composite, though having a reduced thermal conductivity compared to pure metals, is designed to meet specific heat transfer requirements where controlled heat conduction is desirable. [9] Moreover, the Coefficient of Thermal Expansion (CTE)—a property that dictates the material’s dimensional response to temperature variations—presents a compelling challenge in MMC design. The inherent difference in CTE between the metal [10] formation at the interface, potentially compromising the material’s structural integrity over time. However, by carefully selecting reinforcements with low CTEs, the resulting composite can be tailored to minimize this thermal mismatch, reducing the risk of thermal-induced failure and enhancing long-term performance. Further complicating the thermal landscape of MMCs is their heat capacity, a critical measure of the material’s ability to store thermal energy. The specific heat capacity of MMCs, typically lower than that of pure metals, is influenced by the reinforcing phase, which generally exhibits a lower specific heat. While this may limit the material’s ability to store heat, it aligns with the performance demands of applications where heat dissipation is prioritized over heat storage, such as in heat sinks and engine components.

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