Medium-entropy (Ti, Zr, Hf)₂SC MAX phase

Medium- and high-entropy alloys or ceramics for tuning the physicochemical properties of materials by the combination of multiple principal elements have received much interest. Herein, a medium-entropy (Ti, Zr, Hf)₂SC phase was synthesized attributing to the structural and chemical diversity of MAX phases. The crystal structure of (Ti, Zr, Hf)₂SC was determined by the Rietveld refinement of XRD, SEM, and atom-resolved TEM along with EDS elemental analysis. Phase evolution of X-ray diffraction patterns and TG/DSC curves were employed to reveal the synthesis mechanism of (Ti, Zr, Hf)₂SC from 2TiC–Zr–ZrC-2HfH₂-3.2FeS reactant system. The Vicker's hardness and the electrical resistivity of (Ti, Zr, Hf)₂SC were found higher than those of Ti₂SC, but the thermal conductivity of (Ti, Zr, Hf)₂SC was lower.