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Page 10 of 12 Liu et al. J Mater Inf 2022;2:20 https://dx.doi.org/10.20517/jmi.2022.29

where Z is the partial CN, equal to the average number of B-type atoms in the nearest coordination shell
A(B)
of A-type atoms; f is the fraction of B-type atoms in HEMGs; the average CN of A-type atoms Z = Σ Z .
B
A
X A(X)
The -α is displayed in different colors in Figure 5C, and the values are given out only for the total average.
A(B)
If LAs/SAs have a higher -α than the total average, the corresponding areas are marked by a plus sign,
A(B)
otherwise by a minus sign. The symbol “0” means the change is lower than 0.03, and the double plus/minus
sign indicates the change is larger than 0.09. Firstly, the colors in Figure 5C show the chemical preference of
coordination. Among all pairs, Cu-Zr, Zr-Ni, Ti-Pd, and Pd-Pd are the most favored bonds. On the
contrary, Ni-Pd, Cu-Ni, Pd-Cu, and Cu-Cu pairs are relatively rare in this HEMG. It might be associated
with mixing enthalpy. The favored pairs have relatively large negative mixing enthalpy, such as
-1 -1 -1
Cu-Zr (-23 kJ·mol ), Zr-Ni (-49 kJ·mol ) and Ti-Pd (-65 kJ·mol ), while the unfavored pairs have small
-1
-1
negative values, such as Ni-Pd (~0 kJ·mol ), Pd-Cu (-14 kJ·mol ), and even positive for
-1 [46]
Cu-Ni (4 kJ·mol ) . Secondly, the symbols (i.e., +, -, and 0) in the LA/SA-quarter reveal the characteristics
of LAs and SAs by the degree of deviation from the total average. Observing by columns, the Ni column has
the most double signs, which means a dramatic variation in the chemical environment around Ni atoms
when Ni serves as LAs/SAs. As we observed by rows, many “0’s” in the (Cu) row indicate that around LAs
and SAs there is no apparent change in the number of Cu atoms. From the rows of (Zr) and (Ni), there is an
obvious reduction in Zr and Ni atoms around LAs but increasing around SAs. By contrast, the Ti and Pd
atoms favor pairing around LAs but avoid existing near SAs. According to Figure 5C, it is worth noting that
every sign of LAs is opposite to that of SAs, suggesting their great contrast in chemical short-range order. In
the conventional Cu-Zr binary MG, the LAs and SAs have almost negligible deviation of α parameter from
[34]
the total average . Compared with the weak chemical short-range order in the conventional MG, such a
great variation in the HEMG should be caused by the high entropy effect.

CONCLUSIONS
Through learning the atomic dynamics, a kNN model successfully predicted the “temperature” of individual
atoms in the Cu Zr Ni Ti Pd HEMG, which can serve as a parameter to identify the active/inactive
20 20 20 20 20
atoms under thermal and mechanical stimuli. During the stress-induced plastic flow, the machine-learned
temperature revealed the heterogeneity in atomic dynamics. With the increase of the applied stress, a
growing number of atoms are activated and move like “hot” atoms. These active “hot” atoms show an
isolated and heterogeneous spatial distribution, and they have a close connection with local plastic
deformation. Structurally, the active LAs prefer the lower LFFS and less CN atomic packing. Chemically,
LAs and SAs exhibit the completely opposite characteristic of chemical short-range order. Compared with
the conventional MG, the HEMG has a smaller activation volume of creep, a lower fraction of active atoms
that make an ineffective contribution to viscoplastic deformation, and a more pronounced chemical
short-range order, which corroborates the sluggish dynamics and high entropy effect of HEMGs.

DECLARATIONS
Acknowledgments
We thank Quanfeng He for contributing discussion on the article.

Authors’ contributions
Designed the study and performed data analysis and interpretation: Liu X
Performed data acquisition and provided technical support: Lu W
Made substantial contributions to writing and discussion: Tu W
Made contributions to conception and supervised the research: Shen J