Metal matrix nanocomposites (MMNCs) are those metal matrix composites where the reinforcement is of nanometer dimensions, typically less than 100 nm in size. Also, it is possible to have both the matrix and reinforcement phases of nanometer dimensions. The improvement in mechanical properties of MMNCs is attributed to the size and strength of the reinforcement as well as to the fine grain size of the matrix. Spark plasma sintering has been used extensively over the past years to consolidate wide range of materials including nanocomposites and was shown to be effective noneconventional sintering method for obtaining fully dense materials with preserved nanostructure features. The objective of this work is to briefly present the spark plasma sintering process and review published work on spark‐plasma‐sintered metals and metal matrix nanocomposites.

Heat sinks are commonly used for cooling electronic devices and high-power electrical systems. The ever-increasing performance of electronic systems together with miniaturization calls for better heat dissipation. Therefore, the heat sink materials should not only have high thermal conductivities, low densities, and cost, but also have coefficients of thermal expansion matching to those of semiconductor chips and ceramic substrates. As traditional materials fail to meet these requirements, new composite materials have been developed with a major focus on metal matrix composites (MMCs). MMCs can be tailored to obtain the desired combination of properties by selecting proper metallic matrix and optimizing the size and type, volume fraction, and distribution pattern of the reinforcements. Hence, the current review comprehensively summarizes different studies on enhancing the thermal performance of metallic matrices using several types of reinforcements and their combinations to produce composites. Special attention is paid to the types of commonly used metallic matrices and reinforcements, processing techniques adopted, and the effects of each of these reinforcements (and their combinations) on the thermal properties of the developed composite. Focus is also placed on highlighting the significance of interfacial bonding in achieving optimum thermal performance and the techniques to improve interfacial bonding.