Lightweight high-strength metal matrix nano-composites (MMNCs) can be used in a wide variety of applications, e.g., aerospace, automotive, and biomedical engineering, owing to their sustainability, increased specific strength/stiffness, enhanced elevated temperature strength, improved wear, or corrosion resistance. A metallic matrix, commonly comprising of light aluminum or magnesium alloys, can be significantly strengthened even by very low weight fractions (~1 wt%) of well-dispersed nanoparticles. This review discusses the recent advancements in the fabrication of metal matrix nanocomposites starting with manufacturing routes and different nanoparticles, intricacies of the underlying physics, and the mechanisms of particle dispersion in a particle-metal composite system. Thereafter, the microstructural influences of the nanoparticles on the composite system are outlined and the theory of the strengthening mechanisms is also explained. Finally, microstructural, mechanical, and tribological properties of the selected MMNCs are discussed as well.

The room temperature mechanical properties and high temperature creep behavior of AZ91 alloy reinforced with SiCp synthesized via stir casting have been evaluated. The mechanical properties showed improvement with respect to the amount of reinforcement content. The creep testing of the composites carried out at a temperature of 175 °C under constant stress of 80, 100 and 120 MPa reveals different creep characteristics depending upon the reinforcement content and the applied load. The true stress exponents of different composites calculated from minimum creep rate indicate the possible mechanisms of creep deformation