Equiatomic, Cu‐Containing CrCuFeTiV 3d Transition Metal High Entropy Alloy with an Enhanced Strength and Hardness Synergy

A novel 3d transition metal high entropy alloy (TM HEA), CrCuFeTiV, was fabricated by arc-melting under a vacuum condition. Its phase component, microstructure, and compressive properties in the as-cast and annealed conditions were carefully investigated. The experimental results showed that the alloys in both conditions consist of one BCC phase (CrV/FeTi-rich regions), one FCC phase (Cu-rich), and one hexagonal Laves phase (Cr2Ti). It is suggested that the CrV-rich BCC phase preferentially separates as dendritic centers. Subsequently, the Cr2Ti Laves phase and the FeTi-rich BCC phase solidify as a dendritic outer layer. Finally, the FCC Cu-rich phase is squashed into the remaining interdendritic regions. Besides, the yield strength, ultimate strength, and hardness of the as-cast CrCuFeTiV alloy are 1686 MPa, 2205 MPa, and 624 HV, while those for the annealed alloy are 1510 MPa, 2035 MPa, and 618 HV, respectively. The obtained values are the highest among the tabulated five-principle equiatomic Cu-containing 3d TM HEAs. The promising strength-hardness synergy of CrCuFeTiV alloy is likely originated from the majority constitution of the BCC phase and Cr2Ti Laves phase.