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Magnesium (Mg) composites reinforced with carbon-based nanomaterial (CBN) often exhibit low density, enhanced strength, good conductivity, improved wear resistance, and excellent biocompatibility when compared to current industry Mg alloys. This review aims to critically evaluate recent developments in Mg-CBN composites and is divided into five sections: First, a brief introduction to Mg-CBN composites is provided, followed by a discussion of different fabrication techniques for these composites, including powder metallurgy, casting, friction stir processing, and selective laser melting. A particular focus is on the current processing challenges, including dispersion strategies to create homogeneous Mg-CBN composites. The effect of processing on the quantifying disorder in CBNs and distinguishing different sp2 carbon materials is also highlighted. Then, the effect of CBN on various properties of Mg-CBN composites is thoroughly analyzed, and the strengthening efficiency of CNTs and graphene in the Mg matrix is examined. Finally, the potential applications of Mg-CBN composites in various industries are proposed, followed by a summary and suggestions for future research directions in the field of Mg-CBN composites. [ABSTRACT FROM AUTHOR]

In this study, functionally graded ZrB2–B4C–SiC–LaB6 composite materials (FGMs) with potential applications in hypersonic aircraft thermal protection systems were fabricated using spark plasma sintering. A systematic study of the thermal conductivity of the FGM, the conductivity of respective FGM layers, and the equivalent non-graded composites, was performed from room temperature up to 450 °C. The results suggest that the thermal conductivity of the FGMs (in the through-thickness direction) and their equivalent non-graded composites ranged between 25 and 34.9 W/mK, which was ∼60 % less than ZrB2. While the overall thermal conductivity of the FGM and equivalent non-graded composites were similar, in the FGM, the topmost layer with high ZrB2-content displayed up to 245 % higher thermal conductivity than the bottom layer with high B4C content. A systematic comparison between experimentally determined conductivity and relevant thermal conductivity models was conducted.