Dynamic Recrystallization Behavior of GH4586 Superalloy during Hot Compression

Abstract

Compression test for GH4586 superalloy was carried out at 1273 K and 1373 K with stain from 20% to 60%. The characteristics of dynamic recrystallization were investigated by confocal laser scanning microscope, TEM and EBSD. It was found that at 1273 K dynamic recrystallization mainly took place along preexisting grain boundaries creating a necklace structure. It was confirmed by TEM observations that the first layer of the necklace structure was formed by the mechanism of bulging of preexisting grain boundaries and the following layers were nucleated at the triple junctions of former dynamic recrystallization grains. When specimens were deformed with different strains at 1373 K, dynamic recrystallization was almost completed. Our observation showed that twinning played an important role during dynamic recrystallization by promoting dynamic recrystallization grains growing. Substructures of grains were constructed by the reconfiguration of dislocations hindered at large ' particles in interior of initial grains during dynamic recovery.