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Liu et al. J Mater Inf 2022;2:20 https://dx.doi.org/10.20517/jmi.2022.29 Page 5 of 12

Figure 1. Machine-learned temperature, T vs. actual temperature, T. (A): Cu atoms; (B): Zr atoms; (C): Ni atoms; (D): Ti atoms; (E):
ML
Pd atoms; (F): total atoms. ML: Machine learning.
As illustrated in Figure 2A, a tensile test was first simulated at T = 100 K to measure the σ , which was
max
usually defined as yielding in a simulation . Subsequently, three creep stresses lower than σ were chosen,
[38]
max
i.e., σ = 2.2, 2.3, and 2.4 GPa. The creep curves on the holding stage are plotted in Figure 2B. The transient
h
and steady-state creep stage can be observed on all curves, whereas the tertiary stage with the rapid increase
in strain rate only occurs on the curve of σ = 2.4 GPa within the time window. During the stress holds, local
h
irreversible atomic rearrangements are continually activated and lead to the macroscopic viscoplastic flow.
According to Zhang et al., the activation volume can be fitted from the relation of the applied stress σ and
steady-state strain rate , as expressed by Ω = k T∂ln /∂σ, where k is Boltzmann constant . The
[22]
B
B
3
activation volume of the HEMG is 27 nm smaller than that of Cu Zr MG (31 nm fitted from the curves
3
50
50
[22]
[34]
in Ref. ), consistent with the experimental results . Note that the smaller activation volume of
the HEMG may be due to its smaller molar volume, if we assume that the HEMG sample has the same
atomic packing density as the Cu Zr .
50
50
To reveal the stress-induced heterogeneity in atomic dynamics, we applied the kNN model to predict T ML
for every atom. The histograms in Figure 2C statistically display the distributions of T . If there is no
ML
applied stress on the HEMG sample, the T will have a Gaussian distribution, which means that the atomic
ML
motion is activated by thermal agitations and corresponds to only one characteristic temperature. In
Figure 2C, there is a maximum at T = ~300 K. It is reasonable to find the peak at T = 300 K rather than
ML