MXenes derived from MAX phases as reinforcements in aluminium and aluminium-alloy matrix composites: Synthesis, processing, interfacial science, mechanical behaviour and tribology – A critical review

MXenes, two-dimensional (2D) transition-metal carbides and nitrides obtained by selectively etching layered MAX phases, are a distinctive reinforcement for aluminium because their native surface terminations can promote wetting and interfacial bonding. This review critically evaluates the literature on MXene-reinforced aluminium and aluminium-alloy matrix composites, covering synthesis, processing, interfacial science, mechanical behaviour and tribology. Ti 3 C 2 T x dominates the field. Its processing is constrained by termination loss on heating, lattice transformation at elevated temperature, oxidation in air or water, and reaction with aluminium near the melt-processing regime. Solid-state consolidation is therefore preferred when flakes must be preserved, although vacuum induction melting has produced strengthened composites in which part of the MXene is retained. A descriptive cross-study normalisation of tensile data shows the largest strength gain per vol.% for few-layer flakes at the lowest loading; because matrix, processing route and microstructure differ between studies, this trend is a correlation, not proof of cause. Classical strengthening models are used only as sensitivity tools. Bulk MXene/Al tribology data remain scarce and are separated from coating evidence. The effects of Mg, Si and Cu, oxidation during consolidation, and flake orientation and fragmentation are examined, published micrographs are assessed, and experimentally testable research priorities are proposed.