Abstract The metastable phase separation and physical property of rapidly solidified CoCrFeNiCux (x = 0,1,2) HEAs were investigated by glass fluxing technique. The maximum undercoolings were achieved by 365 K (0.21 TL), 381 K (0.23 TL) and 236 K (0.14 TL) for these alloy melts respectively. Once the Cu element was added into the CoCrFeNi HEA, the metastable phase separation took place and caused the formation of two obvious segregation zones when alloy undercooling exceeded a critical undercooling. The dendritic growth velocity increased with undercooling and declined gradually with the enhancement of Cu content. The microhardness of CoCrFeNi and CoCrFeNiCu HEAs increased with the undercooling owing to the refined microstructures, but that of CoCrFeNiCu2 HEA increased firstly and then declined with its undercooling because of phase separation.

中文翻译：

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快速凝固高熵 CoCrFeNiCux 合金的相分离和显微硬度

摘要 采用玻璃熔剂技术研究了快速凝固的CoCrFeNiCux (x = 0,1,2) HEA 的亚稳态相分离和物理性质。这些合金熔体的最大过冷度分别为 365 K (0.21 TL)、381 K (0.23 TL) 和 236 K (0.14 TL)。一旦将Cu元素加入CoCrFeNi HEA中，当合金过冷度超过临界过冷度时，发生亚稳态相分离并导致形成两个明显的偏析区。枝晶生长速度随着过冷度的增加而增加，随着Cu含量的增加而逐渐下降。CoCrFeNi和CoCrFeNiCu HEA的显微硬度因显微组织细化而随过冷度增加而增加，而CoCrFeNiCu2 HEA的显微硬度随过冷度因相分离而先增加后下降。