On the room-temperature tensile deformation behavior of a cast dual-phase high-entropy alloy CrFeCoNiAl0.7

Abstract

The microstructure and room-temperature tensile deformation behavior of the cast CrFeCoNiAl0.7 high-entropy alloy (HEA) were studied in details. The cast HEA consisted of a dual-phase structure of 77. 3 vol. % face-centered-cubic (FCC) phase plus 22.7 vol.% B2 phase, and exhibited excellent room-temperature tensile properties with a high yield strength of 876 MPa, ultimate tensile strength of 1198 MPa and a relatively large elongation to fracture of ∼9 %. Dislocations gliding in the FCC phase governed the plastic deformation at the early stage of room-temperature tensile, and disordered dislocations were to form dislocation walls as the deformation proceeded. With further increase in strain to a high level, the stacking faults were generated through the dissociation of the geometrically necessary dislocations, serving as the potential heterogeneous nucleation sites for the deformation twins.