  Recent observations of jerky flow in high-entropy alloys (HEA) revealed a
high role of self-organization of dislocations in their plasticity. The present
work reports first results of investigation of stress fluctuations during
plastic deformation of a FeCoNiTiAl alloy, examined in a wide temperature range
covering both smooth and jerky flow. These fluctuations, which accompany the
overall deformation behavior representing an essentially slower stress
evolution controlled by the work hardening, were processed using complementary
approaches comprising the Fourier spectral analysis, the refined composite
multiscale entropy, and multifractal formalisms. The joint analysis at distinct
scales testified that even a macroscopically smooth plastic flow is accompanied
with nonrandom fluctuations, disclosing self-organized dynamics of
dislocations. Qualitative changes in such a fine-scale "noise" were found with
varying temperature. The observed diversity is significant for understanding
the relationships between different scales of plasticity of HEAs and crystal
materials in general.
