Serration behavior and brittle phase-induced mechanical transitions in wrought Al0.3CoCrFeNi high-entropy alloy from 100°C to 800°C

Abstract

In this work, the serrated flows and temperature-dependent behavior of Al0.3CoCrFeNi were investigated. The refined composite multiscale entropy (RCMSE) method was used to model and analyze the serration behavior. The results revealed that serrated flow exhibited dynamically complex behavior, with complexity increasing with temperature. Experimental results showed that the serration type changed from type-A (regular, high-frequency serrations associated with dynamic strain aging (DSA) effects) and type B (irregular, medium-frequency serrations linked to localized dislocation motion) to type-C (low-frequency, large-amplitude serrations caused by interactions between deformation twins and dislocations) between 300°C and 600°C due to the transition from dynamic strain aging (DSA) effects to interactions between deformation twins and dislocations. Additionally, grain boundary segregation led to a transition from ductile to brittle fracture at 700°C. These findings highlight the significance of understanding serration and temperature-dependent behaviors during the deformation of the Al0.3 alloy, which is crucial for research on the temperature-dependent failure and application of high-entropy alloys.