Self-healing behavior of Inconel 617B superalloy

In the present study, the self-healing behavior of Inconel 617B superalloy (617B), used as a high-temperature material, was investigated through both preliminary test consisting of room-temperature tension and annealing and creep rupture test. Micro-cracks in the solution-treated specimen, which had been fractured at room temperature, were filled in by the precipitation of M₂₃C₆ and the segregation of B, C, and S after annealing at 800 °C for 16 h. Due to this healing effect and dislocation recovery, a 33% pre-strained and annealed specimen exhibited the longer total elongation, compared to the specimen strained until fracture without annealing after 33% pre-strain. Finally, creep rupture tests revealed that the creep strength of 617B is higher than Inconel 617 superalloy (617) due to the self-healing effect by the high-temperature precipitation of M₂₃C₆ and the segregation of B, C, and S as well as grain boundary strengthening of B and C.