| Abstract Scope |
This study focused on duplex systems in High Entropy Alloys (HEAs), which are primarily composed of face-centered cubic (FCC) or body-centered (BCC) structures. However, limited information is available regarding HEAs containing both FCC and BCC phases. To address this gap, thermodynamic calculations were conducted to identify four non-equiatomic compositions in the CrCoNi and CrCoNiAl systems, enriched with high levels of Cr and Co, to form duplex structures (FCC/BCC). Incorporating aluminum Al expanded the duplex field by stabilizing the BCC phase, allowing for increased ductility by adding more cobalt to the alloys. The alloys underwent characterization in various conditions, including as cast, homogenized, cold rolled, and recrystallized states, using optical microscopy, X-ray diffraction (XRD), and Vickers micro hardness. The findings demonstrated that the alloys Co15Ni33.5Cr51.5, Co15Ni32Cr48Al5, and Co34Ni16Cr45Al5 exhibited a dual-phase structure. Conversely, the Co35Ni15.5Cr49 alloy did not possess a duplex structure, due to the narrow duplex field predicted by CALPHAD. |