Effects of hot extrusion on microstructure and mechanical properties of Mg matrix composite reinforced with deformable TC4 particles

Mg matrix composites were often reinforced by non-deformable ceramic particles. In this paper, a novel Mg matrix composite reinforced with deformable TC4(Ti–6Al–4V) particles was fabricated and then extruded. The evolutions of microstructure and mechanical properties of the composite during hot extrusion were investigated. Hot extrusion refined grains and eliminated the segregation of TC4 particles. TC4 particles, as deformable particles, stimulated the nucleation of dynamic recrystallization during extrusion. However, since the deformation of TC4 particles partly released the stress concentrations around them, the recrystallized grains are just slightly smaller around TC4 particles than that away from them, which is evidently different from the case in Mg matrix composites reinforced by non-deformable ceramic particles. Compared with AZ91 matrix composites reinforced by Si C particles, the present composite possesses the superior comprehensive mechanical properties, which are attributed to not only the strong interfacial bonds between TC4p and matrix but also the deformability of TC4 particles.