LAUSR

Abstract High-entropy metal boron carbonitride ceramic powders including (Ta0.2Nb0.2Zr0.2Hf0.2W0.2)BCN, (Ta0.2Nb0.2Zr0.2Hf0.2Ti0.2)BCN, and (Ta0.2Nb0.2Zr0.2Ti0.2W0.2)BCN, were successfully synthesized via mechanical alloying at room temperature. Results show that for the first step of 10 h milling, the amorphous BCN phases are observed. After 24 h of second step milling, the as-synthesized high-entropy ceramics exhibit a single face-centered cubic solid solution structure with high compositional uniformity from nano-scale to micron-scale. When heated to 1500 °C for 30min in flowing Ar, the as-prepared high-entropy ceramic powders still show relatively high thermal stability; however, some metals oxides like HfO2 and ZrO2 are detected due to the pre-existing oxides on sample surfaces. After heat treatment, some amorphous phases are still retained. This work suggests a new processing route on the synthesis of high-entropy metal boron carbonitride ceramics.