Impact of 3d TM elements on Cu segregation in CrCuTiV-based high entropy alloys and their mechanical properties

Abstract

As Cu segregation is commonly known to negatively impact the comprehensive mechanical properties of Cu-containing high entropy alloys (HEAs), this study investigated the effects of transition elements on Cu segregation by adding X (X = Fe, Co, and Ni) into the precursor HEA, CrCuTiV. Cu segregation was observed in the cases of X = Fe or Co, but not for X = Ni or none (i.e., without element addition). Analysis indicates that Cu segregation results from the moderate valence electron concentration and positive mixing enthalpy in the X = Fe and Co alloys, which enhance the strength via solid solution strengthening but reduce the plasticity by promoting crack formation and propagation. In contrast, the precursor alloy CrCuTiV demonstrated an exceptional combination of yield strength (1456 MPa), plasticity (21.2%), and specific yield strength (218.3 kPa m3/kg). The study sheds light on the influence of similar 3d elements on Cu segregation and its impact on the mechanical properties, which may aid in the design and development of Cu-containing HEAs with optimized mechanical properties for various industrial applications.