Microstructure and mechanical properties of textured high-entropy M4AlC3/Al2O3 (M = Ti, V, Mo, Nb, Ta) composites

High-performance MAX phase-based composites were developed to overcome the inherent low hardness and low strength of MAX phases by combining lattice distortion-induced strengthening, texture strengthening, and second-phase particle strengthening. Textured high-entropy M4AlC3/Al2O3 (M = Ti, V, Mo, Nb, Ta) composites with different Al2O3 contents were prepared using spark plasma sintering at 1350 degrees C for 70 min. The microstructures of all samples with different compositions were characterized in detail. It was found that as the Al2O3 content increased, the grain size of the high-entropy M4AlC3 phase gradually decreased, and the aggregation of Al2O3 became more severe. Based on this, the density, hardness, strength, and fracture toughness of all composites were tested. The results indicate that all textured composites exhibit significant anisotropy in their properties, with the high-entropy M4AlC3/15 vol%Al2O3 composite showing the best overall performance. Additionally, the mechanism of performance improvement was systematically discussed. This work provides an important reference for the subsequent preparation of high-performance MAX phase-based composites.