Imposition of electric current to promote the Portevin-Le Chatelier effect of CoCrFeMnNi high-entropy alloy at low temperatures

The effect of electric current on Portevin-Le Chatelier (PLC) effect of CoCrFeMnNi high-entropy alloy (HEA) was investigated. Compared with previous studies, PLC effects were firstly observed at much lower temperatures than 275 °C. Theoretical analysis based on the experimental results indicates that the electromigration effect and the increased concentration of vacancies induced by electric current can significantly improve the mobility of solute atoms in CoCrFeMnNi HEA. Together with the increased dislocation density, the enhanced mobility of solute atoms can facilitate the repeated locking and unlocking process of mobile dislocations by the solutes during plastic deformation process. Consequently, this leads to the promoted PLC effect at lower temperatures, which is also supported by TEM analysis and the estimated higher activation energy of 285.4 kJ mol⁻¹ between 275 °C and 325 °C.