Stir Casting Routes for Processing Metal Matrix Syntactic Foams: A Scoping Review

Metal matrix syntactic foams (MMSFs) are advanced lightweight materials constituted by a metallic and dispersion of hollow/porous fillers. Physical mechanical properties can be fitted regarding filler processing parameters. Their make them potential for sectors where density is limiting parameter, such as transport, marine, defense, aerospace, engineering applications. MMSFs mainly manufactured powder metallurgy, infiltration, stir casting techniques. This study focuses on the current approaches advances deficiencies, providing parameters comparative analyses porosity properties. PRISMA were followed to favor traceability reproducibility study. Stir techniques low-cost, industrially scalable approaches, but they exhibit critical limitations: buoyancy fillers, corrosion equipment, premature solidification molten metal during mixing, cracking heterogeneous distribution, limited incorporation Six different identified; four focus buoyancy, cracking, distribution excessive oxidation sensitive alloys oxygen. These improvements reaching maximum 54%, increasing fillers’ size from few microns 4–5 mm, reducing residual ±4%, synthesizing bimodal MMSFs, 74 vol%.