Synthesis of a novel textured high entropy M4AlC3 (M = Ti, V, Mo, Nb, Ta) composites with improved mechanical properties via spark plasma sintering

Abstract

A novel high-entropy M4AlC3 phase ceramic (M=Ti, V, Mo, Nb, Ta) was synthesized by three-step solid phase sintering, and the textured high-entropy M4AlC3 composites were prepared for the first time by SPS uniaxial pressing of nano flakes generated via reactive ball milling. The microstructure were characterized in detail and Maud software was used for Rietveld refinement analysis of phase composition content. The results showed that Ti, V, Mo, Nb, Ta were successfully dissolved in M4AlC3. On this basis, the density, hardness and mechanical properties before and after texture were tested. The results showed that the textured composite achieved 12.1 GPa Vickers hardness (//C-axis), 2.2 GPa compressive strength (//C-axis), 8.8 fracture toughness of MPa m1/2 (//C-axis) and 726 MPa bending strength (//C-axis). Dispersively distributed nano-Al2O3 and texturization played a key role in strengthening and toughening. This work can provide an important reference for the subsequent preparation and texturing of high-entropy MAX ceramics.