A Review of the Serrated-Flow Phenomenon and Its Role in the Deformation Behavior of High-Entropy Alloys

Abstract

High-entropy alloys (HEAs) are a novel class of alloys that have many desirable properties. The serrated flow that occurs in high-entropy alloys during mechanical deformation is an important phenomenon since it can lead to significant changes in the microstructure of the alloy. In this article, we review the recent findings on the serration behavior in a variety of high-entropy alloys. Relationships among the serrated flow behavior, composition, microstructure, and testing condition are explored. Importantly, the mechanical-testing type (compression/tension), testing temperature, applied strain rate, and serration type for certain high-entropy alloys are summarized. The literature reveals that the serrated flow can be affected by experimental conditions such as the strain rate and test temperature. Furthermore, this type of phenomenon has been successfully modeled and analyzed, using several different types of analytical methods, including the mean-field theory formalism and the complexity-analysis technique. Importantly, the results of the analyses show that the serrated flow in HEAs consists of complex dynamical behavior. It is anticipated that this review will provide some useful and clarifying information regarding the serrated-flow mechanisms in this material system. Finally, suggestions for future research directions in this field are proposed, such as the effects of irradiation, additives (such as C and Al), the presence of nanoparticles, and twinning on the serrated flow behavior in HEAs.

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“…Beyramali Kivy et al [1] reviewed the computational tools for studying the structure and properties of multi-principal alloys and identified the advantages as well as limitations of simulations in accelerating design and development of new alloys. The unique deformation mechanisms of concentrated alloys are discussed in one review article and two research papers in this special issue [2][3][4]. Brechtl et al [2] reviewed the serration behavior during deformation in HEAs and its dependence on composition, microstructure, and testing condition (i.e., strain rate and temperature).…”

Original Fe–Co–Ni–Ga–Nb Multicomponent Alloy with Soft Magnetic Properties

“…The high entropy of mixture hinders the growth of complex phases, and the low diffusivity slows down phase transformations. For many applications, properties typically considered relevant are corrosion resistance, strength, ductility, and deformation behavior, [ 7–9 ] especially for high‐temperature structural materials. However, in HEAs’ magnetic materials an important factor is the severe distortion of the lattice, which influences many physical properties.…”