Effects of Gd element and SiC particles on microstructures of Cf/Mg composites

•Gd element segregated on the surface of SiC particles as well as the carbon fibers.•The Gd element reacted with the SiC particles and forms GdC2 on the surface.•The precipitation forming on the carbon fibers were concluded to be nano-scaled Gd2O3.•The interface layers on the Cf in the hybrid reinforced composite was much thinner.

In present work, Cf/Mg-8Gd and SiC+Cf/Mg-8Gd composites were fabricated by squeeze infiltration method. Gd2O3 coating layers were found on the surface of the carbon fibers in these two kinds of the composites, while GdC2 precipitations were found in the hybrid reinforced composite only. Owing to this phenomenon, the coating layer in SiC+Cf/Mg-8Gd composite (88 nm) was much thinner than the one without the SiC particles (160 nm). The Gd2O3 coating layer formed on the surface of carbon fibers can improve the wettability between carbon fibers and magnesium alloy.