Influence of mutual substitution between Cu and Ti on phase components, microstructures, and compressive properties of AlFeNiV–Cu/Ti alloys

Two 3d transition metal high-entropy alloys (3d TM HEAs), AlFeNiVCu and AlFeNiVTi, were suction cast under identical conditions into a cylinder copper mould for investigating the compositional dependence of phase components, microstructures, and compressive properties. The phase components of the AlFeNiVCu were composed of a BCC FeV-rich dendritic phase, a netlike FCC Cu-rich interdendritic phase, and a uniformly distributed B2 AlNi-rich phase, when Cu substituted by Ti the phase components transformed to two BCC solid solution phases of the AlFeNiVTi. Moreover, an outstanding synergy in strength and ductility (ultimate compressive strength: 1936 MPa, plastic strain: 10.0%) was acquired for the AlFeNiVCu, which was sharply contrast with the typically brittle behaviour at the ultimate strength of 108 MPa for the alloy AlFeNiVTi. The distinctions of phase components and morphology were analysed to uncover the conflict in mechanical performance by Cu and Ti mutual substitution in AlFeNiV-base alloys.