The ion exchange promoted interfacial strength in magnesium based composites

Fiber/matrix interfacial chemistry in alumina fiber (Saffil) reinforced Mg and MgLi matrix composites is studied by means of SEM, XPS, AES and XRD concluding that lithium is a dominant reaction agent while the role of magnesium is marginal. The reaction pathway of lithium includes: (i) formation of Li 2O by the displacement redox reaction and (ii) formation of spinel-like phase δ(Li) in the reaction couple Li 2O/δ-Al 2O 3 via topotactic insertion of Li + into δ-Al 2O 3 lattice (presumably by the ion exchange). This reaction sequence contributes to the reactive wetting thus promoting fiber/matrix interfacial strength in MgLi composites.