Novel single phase (Ti0.2W0.2Ta0.2Mo0.2V0.2)C0.8 high entropy carbide using ball milling followed by reactive spark plasma sintering

Abstract

Single phase novel (Ti0.2W0.2Ta0.2Mo0.2V0.2)C0.8 high entropy carbide (HEC) compacts were successfully synthesized by reactive spark plasma sintering of ball milled metal-carbon elemental mixture at temperatures of 1400−1800 °C. X-ray diffraction and element distribution maps indicated single phase carbide formation with lattice parameter ranging from 4.307 Å to 4.312 Å with small amount of TiO2. X-ray energy dispersive spectroscopy (EDS) mapping showed uniform distribution of the transition metals in the carbide phase. The microhardness, elastic modulus, fracture toughness, electrical resistivity and thermal expansion coefficient (25 °C–600 °C) of the compact sintered at 1800 °C were found to be 25.8 ± 2.8 GPa, 461 ± 36 GPa, 3.7 ± 0.4 MPa.m1/2, 7 × 10−4 Ω/m2 and 7 × 10-6 K−1 respectively.