Unveiling segregation-induced evolution in phase constitution of Cu-containing high-entropy alloys

Microstructures and Mechanical Properties of As Cast (Al7.5Co21.9Cr10.9Ti5.0Fe21.9Ni32.8)100-xCux High-Entropy Alloys

“…Among the three HEAs in this study, Ti, Al, and Cu segregate violently at the DR region. Severe segregation will decrease the ductility of alloys (Yu et al, 2020). The segregation of Ti, Al, and Cu will also lead to a large lattice mismatch at the coherent interface, making these DR regions harmful to tensile strength.…”

“…In contrast, the microstructure of HEAs in some studies (Gwalani et al, 2017) has been relatively fine and uniform, and the ductility and tensile properties of HEAs in these studies have increased with increasing Cu content. Moreover, in other studies (Qin et al, 2019;Yu et al, 2020), the addition of Cu has led to the phase evolution of HEAs, and the mechanical properties of HEAs have been diverse owing to the different phase compositions. Cu has had different modes of effects on HEAs in such studies, so different conclusions have been drawn.…”

“…For example, a pure Cu phase in interdendritic regions was reported in the Co-Cr-Cu-Fe-Ni system (Verma et al, 2019), and a Cu-rich phase was found in interdendritic regions (Wu et al, 2018). The addition of Cu has also revealed different mechanical properties in different studies (Qin et al, 2019;Yu et al, 2020). Yu et al (2020) posited that uncontrollable Cu-segregation during the casting process leads to ambiguous phase constitution, which induces conflicting conclusions.…”

“…The addition of Cu has also revealed different mechanical properties in different studies (Qin et al, 2019;Yu et al, 2020). Yu et al (2020) posited that uncontrollable Cu-segregation during the casting process leads to ambiguous phase constitution, which induces conflicting conclusions. Therefore, further study of the role of Cu is crucial to the composition design and performance improvement of highperformance HEAs.…”

Effect of volumetric energy density on microstructure and tribological properties of FeCoNiCuAl high-entropy alloy produced by laser powder bed fusion

“…For instance, as the Al content increases (x = 0.3, 0.6 and 0.85), the phase of Al x CoCrFeNi HEA changes from a disordered FCC to FCC + disordered BCC, and to BCC + ordered B2 (Joseph et al 2017). In addition, it has been proven that the addition of Cu element can remarkably increase the structural energy difference (ΔE), resulting in a single FCC homogenous FeCoNi(Cu 1.0 Al) x at arbitrary temperatures (ideal state) (Yu et al 2020). This means that Cu, as an FCC stabiliser, could make FeCoNiCuAl HEAs have a dual-phase structure of FCC + BCC.…”