High-entropy carbide ceramics: a perspective review

High-entropy carbide ceramics(HECCs) exhibited a series of property superiority, such as high hardness, high oxidation resistance and adjustable range of thermal conductivity, making them great candidates for structural materials used in extreme service conditions. However, current HECC-related reports can only provide limited guidance for the design of HECC materials with promising properties and stable structure or for their high-quality fabrication. To fill this gap, we proposed in the current review that integrated efforts should be taken in the following three aspects to advance the design and fabrication of high-performance HECCs. First, the rule for the single-phase formation needs to be theoretically identified using high-throughput density functional theory calculations(HTDFT) and a highly accurate predictive model for rapid compositional design warrants establishment through the combination of HTDFT and machine-learning studies. In parallel with the compositional design, the lack of theoretical foundation and guidance for the synthesis of highly dense and highly pure HECC materials necessitates extensive studies focusing on the principle for the synthesis of HECC pre-alloy powders and on the powder densification mechanisms during high-temperature sintering. Moreover, great attentions are to be paid to the mechanistic understandings on the mechanical, oxidation and thermal conduction behaviors of HECC materials; for example, the toughening and strengthening mechanisms of HECC materials could be elucidated through discerning the "HECC composition-stacking fault energy distribution/bonding state-dislocation behavior" correlations.