A novel medium-entropy (TiVNb)2AlC MAX phase: Fabrication, microstructure, and properties

Medium- or high-entropy materials have great potential for applications due to their diverse compositions and unexpected physicochemical properties. Herein, a novel medium-entropy (TiVNb)2AlC was synthesized via hot pressing at 1400 °C from three individual M2AlC (M=Ti, V, Nb) MAX phases. The microstructure of (TiVNb)2AlC was characterized from the microscale to the atomic scale by scanning electron microscope microscopy (SEM), scanning transmission electron microscopy (STEM), and energy dispersive spectroscopy (EDS). The results showed that Ti, V, and Nb atoms were fully solid-soluble in the M-sites of the M2AlC MAX phase. Compared with three individual MAX phases, the thermal conductivity of (TiVNb)2AlC was reduced greatly in the temperature range of 293–1473 K, and its mechanical properties (including Young's modulus, Vickers hardness, and bending strength) were all increased due to the solid solution strengthening and electronic mechanism.