Effect of Boron on the Microstructure Evolution and Dynamic Recrystallization Kinetics of ALLVAC718Plus Superalloy

摘要

In this study, the effect of boron addition on the hot compression behavior and dynamic recrystallization kinetics of 718Plus nickel-based superalloy were investigated by isothermal compression tests at the deformation temperature range of 900-1050 degrees C and strain rate range of 0.01-1 s(-1). Optical and field emission scanning electron microscopy techniques were employed to investigate the microstructural evolutions. The results indicated that the addition of boron reduces the flow stress of 718Plus superalloy. This could be attributed to the decrease in the volume fraction of Ni-3(Al, Ti) particles. Microstructural observations revealed more volume fraction of dynamic recrystallization in the boron-bearing alloy at low-deformation temperatures, i.e., 900 and 950 degrees C. In contrast, at high temperatures of 1000-1050 degrees C, recrystallization is retarded mainly due to the segregation of boron to the grain boundaries.