Abstract Novel AlCrFeNiNb0.3 high entropy alloy (HEA) was cast, heat treated and thoroughly investigated. This alloy exhibits microstructural stability up to 1300 °C and exceptional high hardness values. It is plausible to assume that the reason for these results is relatively large amount of intermetallic phases appearing in this alloy. AlCrFeNiNb0.3 solidifies dendritically. The interdendrite region exhibited typical ternary eutectic microstructure, containing Laves phase, BCC and B2. Dendrite cores were found to be of two types containing either BCC particles embedded in the B2 matrix or vice versa - B2 particles embedded in the BCC matrix. Regardless the type of dendrite's microstructure, this area also contained small particles of highly defected Laves phase and additional Nb-rich nanosized particles with an unknown structure. Latter had faceted rectangular shape with a length of 327 ± 100 nm and width of 70 ± 20 nm. Crystal structure of the unknown phase was investigated by means of electron crystallography and was characterized as cubic, Fm 3 ‾ m, with a = 11.61 A. Structure type was assigned here as Th6Mn23, due to the similarity of lattice parameters and the space group, but it requires further investigation.

中文翻译：

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新型 AlCrFeNiNb0.3 高熵合金：微观结构、性能和未知的富铌金属间化物

摘要 对新型 AlCrFeNiNb0.3 高熵合金 (HEA) 进行了铸造、热处理和深入研究。这种合金在高达 1300 °C 的温度下具有显微结构稳定性和出色的高硬度值。可以假设这些结果的原因是该合金中出现了相对大量的金属间相。AlCrFeNiNb0.3 呈树枝状凝固。枝晶间区域表现出典型的三元共晶组织，包含 Laves 相、BCC 和 B2。发现枝晶核有两种类型，其中包含嵌入 B2 基体中的 BCC 颗粒，反之亦然——嵌入 BCC 基体中的 B2 颗粒。无论枝晶的微观结构类型如何，该区域还包含高度缺陷的 Laves 相的小颗粒和其他结构未知的富含 Nb 的纳米颗粒。后者具有长 327 ± 100 nm 和宽 70 ± 20 nm 的刻面矩形形状。未知相的晶体结构通过电子晶体学进行研究，表征为立方，Fm 3 ‾ m，a = 11.61 A。由于晶格参数和空间群的相似性，这里将结构类型指定为 Th6Mn23，但这需要进一步调查。