Notable advances specific to processing of metal matrix composites: challenges in fabrication and future prospects

Metal matrix composites (MMCs) are increasingly used as lightweight, high-performance alternatives to conventional alloys in aerospace, automobile, and defense applications. Compared to monolithic alloys, metal matrix composites allow property tailoring by adjusting reinforcement content during liquid, solid, or semi-solid-state processing. Despite many advancements in processing routes, some challenges remain, including poor wettability, insufficient densification, particle clustering, and unfavorable matrix–reinforcement reactions. Introducing reinforcements sometimes can make the alloy system “dirtier,” and diminish its properties. Therefore, careful control of wettability, densification, particle distribution, and interfacial reaction is essential to ensure the desired performance of metal matrix composites. This process based review highlights recent advancements in processing techniques and their effect on the microstructure and mechanical properties of metal matrix composites. It also highlights key experimental findings and why significant research is still required to address the limitations preventing metal matrix composites from widely replacing traditional alloys.