LAUSR

Abstract Equimolar CoCrFeMnNi high-entropy alloy (HEA) could be effectively strengthened by grain refinement process. However, the dislocations, grain boundaries and twins determined by the grain refinement process worked as hydrogen diffusion paths and trapping sites may obviously affect the hydrogen induced cracking. In this study, in combination with microstructures and fracture surface morphologies analysis, the HE behavior of CoCrFeMnNi HEA after different recrystallizing annealing processes were studied using slow strain rate tensile (SSRT) tests during in situ electrochemical hydrogen charging. The results indicated that the hydrogen trapping sites such as dislocations and grain boundaries controlled the HE behavior of the alloys. “Low temperature-short time” recrystallizing annealing refined the grains and increased the strength, but heavily decreased the hydrogen embrittlement (HE) resistance due to the residual dislocations along the grain boundaries. However, “High temperature-long time” recrystallizing annealing alloy showed lower strength but very well HE resistance due to the decreasing of grain boundaries and dislocations.