High-entropy intermetallics with striking high strength and thermal stability

• A serious of high-entropy intermetallics based on CoHf-like B2 structure was developed. • The equal atomic ratio six-principal TiZrHfCoNiCu intermetallic has single B2 structure. • The TiZrHfCoNiCu alloy has ultrahigh yield strength of 1.58 GPa and fracture strength of 2.48 GPa. • The TiZrHfCoNiCu alloy exhibits exceptional elevated temperature phase stability up to 900 °C. In this work, we report on a serious of high-entropy intermetallics (HEIs) based on CoHf-like B2 crystal structure. The microstructure evolution and mechanical properties of the targeted TiZrHfCo x Ni x Cu x alloys were detailedly investigated. In particular, the equal atomic ratio TiZrHfCoNiCu intermetallic with single-phase B2 structure shows ultrahigh compressive yield strength of 1.58 GPa and fracture strength of 2.48 GPa. It is striking that TiZrHfCoNiCu intermetallic exhibits a certain toughness and very high elastic strain limit of approximately 1.5%. Furthermore, it can maintain single-phase B2 structure and high strength after annealing at 900 °C, indicating its exceptional elevated temperature phase stability. This work not only broadens the family of high-entropy materials, but also provides a new perspective for the design of superalloys based on multi-principal element intermetallics.