High entropy alloy reinforced lightweight metal matrix composites: A review of the fundamentals, fabrication, properties, and prospects

High Entropy Alloy (HEA) reinforcements represent a transformative approach in advancing lightweight metal matrix composites (LMMCs) for high-performance structural applications. This review examines the integration of HEAs into lightweight metals such as aluminium, magnesium, and titanium matrices and highlights their potential to overcome the limitations associated with traditional ceramic reinforcements. The manuscript covers the fundamentals of LMMCs and HEAs, and particular attention is paid to microstructural evolution, interfacial bonding, and strengthening mechanisms such as load transfer, Orowan looping, and grain refinement. Furthermore, the review discusses the properties imparted by HEAs and emphasises their role in enhancing ductility, hardness, wear resistance and tensile strength of the reinforced composites. Challenges related to particle dispersion, interfacial reactions, and scalability are also explored. By consolidating recent advancements and identifying future research directions, this review shows the promise of HEA-reinforced LMMCs in enabling next-generation materials for aerospace, automotive, marine, and energy applications.