  This chapter presents a literature review of the serrated flow phenomenon in
high-entropy alloys (HEAs). The serrated flow is important as it can result in
permanent macroscopic and microstructural changes in HEAs. The literature
reveals several important findings regarding the effect of strain rate and test
temperature on the serrated flow. Furthermore, this chapter explores the
relationship among the composition, microstructure, testing condition, and
serration behavior. Towards the end of the chapter, a concise summary is
presented for the temperature, strain rate, mechanical-testing type
(compression/tension/nanoindentation), and serration type for HEAs. This
chapter also provides an overview of the different types of analytical methods
that have been successfully implemented to model and analyze the serration
behavior in HEAs. Such techniques include the mean-field theory (MFT)
formalism, complexity-analysis method, and multifractal technique. Finally,
future research topics in this area are presented, such as the effects of
twinning and irradiation on the serration behavior.
