Tao Yang¹, Boxuan Cao¹, Chain Tsuan Liu¹; ¹City University of Hong Kong

Recent studies indicate that high-entropy alloys containing multi-phases have excellent strength and ductility at ambient and cryogenic temperatures. The hardening is mainly due to the precipitation of multicomponent L12 phases with nanoscale particle sizes. However, when tested at elevated temperatures, many high entropy alloys show significant reduction of ductility at intermediated temperatures. In some cases, brittle grain boundary fractures have been observed at 600 to 800C, and embrittlement mechanisms are not well studied at the present time. This talk will be focused on the understanding of the ductility reduction based on the formation of brittle B2, D022, σ and µ phases, environmental effects, and intrinsic grain-boundary weakness at elevated temperatures. Furthermore, the potential ways to eliminate the intermediate-embrittlement will be discussed. (This research is support by the Hong Kong GRF Program under the contract number of CityU11202718).