High-entropy intermetallic compound with ultra-high strength and thermal stability

Abstract The current research of high-entropy alloys (HEAs) is mainly focused on simple solid-solution alloys or alloys with precipitation strengthening phases. In the present work, we developed a series of high-entropy intermetallic compounds (HEICs). In particular, the multi-principal element Fe0.75Co0.75Ni0.75Cu0.75TiZrHf with B2 ordering shows an ultrahigh compressive yield strength of 2.25 GPa and a fracture strength of 2.52 GPa. The developed HEIC also demonstrates exceptional high-temperature phase stability with retained yield strengths up to 905 MPa and 705 MPa at 800 °C and 900 °C, respectively. The underlying phase formation rule of the HEICs is discussed within the framework of a proposed electronegativity related parameter combined with the atomic size dispersity. Our study broadens the family of high-entropy materials and provides a new perspective for the high-temperature alloy design based on multi-principal element intermetallics.