A flow model in CoCrFeMnNi high-entropy alloys during high-temperature tension

Abstract

At high temperatures, serrated flows are frequently observed on the stress–strain curves of single-phase high-entropy alloys, indicating their unique mechanical behavior. In the current study, the CoCrFeMnNi (Cantor alloy) alloy was selected as a model material to further verify the temperature dependence on the serrated flow behavior through continuous temperature variation during tensile tests, which shows a certain strengthening effect of the serrated flow. The lattice strain and dislocation density were calculated at different conditions using the Williamson–Hall (W-H) analysis method. Based on the strain dependence of mobile dislocation density and forest dislocation density, a flow stress model related to the Portevin–Le Chatelier (PLC) effect was proposed to quantify the variation in the PLC behavior with the temperature and its influence on flow stress. The model is beneficial to accurately account for the flow stress during plastic deformation at high temperatures.