High-Entropy Carbides: Processing And Characterization

Abstract

High entropy carbides (HEC) are multi-metal carbides involving at least four types of metal atoms at near-equal concentrations. They exhibit crystalline periodicity and a precise carbon sublattice but display disorder in terms of metal cation packing, therefore they also have unconventional mechanical and physical properties. Up till now, the high entropy carbide compositions presented in literature have been rich in critical raw materials (CRM), such as tungsten (W) and hafnium (Hf). In this research, we aim to design and process sustainable high-entropy carbide compositions free of CRMs. The design of HEC chemistries is performed utilizing high-throughput CALPHAD analyses and further property data is extracted using density functional calculations. Equiatomic metal powder mixtures with carbon were ball milled and conventionally sintered at high 2000ºC temperature to verify the single-phase high entropy carbide formation. XRD, SEM and EBDS techniques were used to characterize the materials and verify HEC formation