Two new 3d transition metals AlCrCuFeTi and AlCrCuFeV high-entropy alloys: phase components, microstructures, and compressive properties

Two 3d transition metal high-entropy alloys, AlCrCuFeX (X = Ti, V), were prepared by a vacuum arc-melting, and their phase components, microstructures, and compressive properties were investigated. The phase components of the alloy with X = V were the BCC + FCC dual-phases, while that of the X = Ti alloy was composed of a multi-phase structure (2BCC + FCC + Laves + L2 1 ). Core–shell structural dendrites, together with discontinuous inter-dendrites formed in the X = Ti alloy, while netlike inter-dendrites surrounded the cellular dendrites in the X = V alloy. Moreover, the X = V alloy possessed a good synergy in strength and plasticity (ultimate strength: 2138 MPa, plastic strain: 7.1%) due to the ameliorating role of the netlike Cu-rich FCC inter-dendrites on the crack extension, while cleavage fracture mechanism for the X = Ti alloy caused by CrTi-rich Laves phase deteriorated its strength and ductility. The high hardness of the AlCrCuFeX alloys with X = Ti and V reaches 714 ± 27 and 565 ± 22 HV, significantly larger than 495 ± 15 HV of the alloy with X = Ni.