Mechanical properties and high-pressure behavior of high entropy carbide (Mo, Nb, Ta, V, W)C

High-entropy carbides (HECs) often exhibit superior mechanical properties compared to single-component carbides. In this work, the (Mo0.2Nb0.2Ta0.2V0.2W0.2)C-0.9 (named as Mo-HEC) was synthesized using the spark plasma sintering (SPS) method. The mechanical properties of Mo-HEC were evaluated using Vickers hardness and nanoindentation tests. The results indicate that Mo-HEC exhibits relatively high toughness, with hardness value surpassing the average hardness of constituent monocarbides. Nanoindentation tests on grains with different orientations revealed an isotropic mechanical behavior of Mo-HEC. Furthermore, the structural stability of Mo-HEC under extreme compression was explored by in situ high-pressure X-ray diffraction. Its cubic structure can be retained up to 58 GPa, and a bulk modulus of 334 GPa was obtained, which is among the highest reported values for HECs. The favorable mechanical properties, structural stability, and high bulk modulus suggest the significant potential of Mo-HEC for applications under extreme conditions.