On the room-temperature tensile deformation behavior of a cast dual-phase high-entropy alloy CrFeCoNiAl_(0.7)

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.