Effects of A-site atoms in Ti2AlC and Ti3SiC2 MAX phases reinforced Mg composites: Interfacial structure and mechanical properties

Abstract

AZ91D magnesium composites reinforced by Ti3SiC2 MAX phase were fabricated by the stir casting technique. Tensile tests reveal that the reinforced effects of Ti3SiC2 and Ti2AlC on Mg matrix are differenent. Unlike Ti2AlC-AZ91D composite for which Ti2AlC delamination happens during the fracture, Ti3SiC2 - AZ91D composite fractures by interfacial debonding mechanisms. Transmission electron microscopy characterization shows that few nanometric Mg grains form in the vicinity of Ti3SiC2 particles, while huge amount of nanometric Mg grains form along with Ti2AlC particles. Elements mapping confirms that Al atoms of Ti2AlC diffuse into Mg matrix. In contrast, no outward diffusion of Si of Ti3SiC2 is observed. This outcome points out that it is possible to regulate the mechanical properties of their relevant Mg composite through adjusting the content of Al and Si in MAX phases, such as Ti3SiAlC2 solid solution.