Cellular structure engineering of additive manufactured CoCrFeMnNi high-entropy composite: The role of hard ceramic reinforcements in elemental segregation of constitutive elements

This study explores cellular structures in TiC/B4C-CoCrFeMnNi high-entropy composites (HECs) fabricated by direct energy deposition (DED) additive manufacturing process, investigating the role of TiC and B4C nano-paticles in enhancing mechanical properties. Despite larger dislocation cell structures and thinner boundaries in TiC/B4C-CoCrFeMnNi HECs compared to CoCrFeMnNi high-entropy alloy (HEA), they exhibit significantly higher hardness and strength, challenging traditional strength-size relationships. Additionally, we examine the behavior of ceramic nano-particles (TiC and B4C) with high melting points relative to matrix CoCrFeMnNi HEA. Rapid scanning prevents full nano-particle melting, leading to distinct element distribution of cell structure. These findings provide insights for selecting suitable nanoceramic particles in HEC development via metal additive manufacturing.