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Ying et al. Microstructures 2023;3:2023018 https://dx.doi.org/10.20517/microstructures.2022.47 Page 9 of 15

Figure 6. (A) Synchrotron X-ray diffraction patterns of [(FeNiCo) Cr ] B sample along the loading direction at different
0.85 0.15 88 12
deformation stages. The inset shows an enlarged view of the evolution of the main peaks. (B) Relationship of lattice strain of FCC and
Cr B-type phases with engineering stress. (C) Texture development (represented by the normalized integrated intensity of different
2
Bragg peaks) in FCC and Cr B-type phases with engineering stress. For clarity, error bars are only shown for selected points on (112)
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and (202) reflections. F and T denote the FCC and tetragonal Cr B-type phases, respectively.
2
can conclude that dislocation slip was the main deformation mechanism for the FCC phase. However, no
distinct texture was formed in the Cr B-type phase.
2

DISCUSSION
Origin of large degree of undercooling
The as-prepared fluxed N-HEAs showed high strength and ductility. One of the key requirements for
forming a network-like structure at the submicron to micron scale is that the deep undercooled liquid state
should be accessible before crystallization . In this work, the degree of undercooling in the centimeter-
[25]
sized B17 N-HEAs could reach values as high as 385 K, showing the great application potential of this alloy.
The fluxing agent B O plays an essential role in reducing the contents of impurities and surface metallic
3
2
oxides in the sample, increasing the undercooling degree . On the other hand, various degrees of chemical
[21]
short-range order can coexist in the molten alloys, due to the complex composition of HEAs , which
[43]
hinders crystallization during undercooling [44,45] . These two mechanisms could explain the large
undercooling of the N-HEAs.

Formation of network morphology in fluxed N-HEAs
One of the possible mechanisms of network structure formation is spinodal decomposition. A liquid-state
miscibility gap may exist in the undercooled liquids of metal-metalloid alloy systems (i.e., Fe-B, Fe-B-C),
due to the existence of unique short-range orders in the undercooled liquids [24,28,46] . The chemical complexity
of the undercooled HEA liquids studied here would facilitate the formation of short-range order ,
[43]
potentially enabling the formation of a metastable miscibility gap. Once sufficient undercooling is reached,