Back stress strengthening dual-phase AlCoCr2FeNi2 high entropy alloy with outstanding tensile properties

The current study reports a novel heterogeneous AlCoCr2FeNi2 high entropy alloy (HEA) with an innovative structure and outstanding mechanical properties at various temperatures. The alloy is composed of the alternating face centered cubic (FCC) phase and the body centered cubic (BCC) phase, with the cubic ordered body centered cubic (B2) phase embedded in the BCC phase and the fusiform BCC phase embedded in the FCC phase homogeneously. The as-cast alloy shows excellent mechanical properties with an ultimate tensile strength of 1330 ± 44 MPa and a total elongation of 7.4%. The mechanical properties are superior to most reported HEAs and are attributed to the strong back stress strengthening effect.