This study explores the microstructural evolution and corrosion resistance of AZ91 magnesium alloy composites reinforced with bioactive glass (BG) particles and processed via friction stir extrusion (FSE), followed by aging heat treatment. The severe plastic deformation induced by FSE transforms the as-cast structure into a refined, equiaxed grain morphology, while subsequent aging promotes the controlled precipitation of β-Mg17Al12 phases. BG particles acting as nucleation sites for precipitates and inhibiting grain coarsening during thermal exposure. These combined effects lead to significant improvements in mechanical performance (yield strength of 285.1 MPa and a hardness of 81.9 HV). Electrochemical analyses indicate that both aging and BG reinforcement enhance corrosion resistance by facilitating the formation of protective surface films and reducing cathodic reaction kinetics.
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