Surface Recrystallization and its Effect on Rupture Life of SRR99 Single Crystal Superalloy

Abstract

The behaviour of surface recrystallization and its effect on rupture life of SRR99 single-crystal superalloy are studied. Results show that the recrystallization at lower temperature (such as 1240'C) is of a cellular mode and the recrystallization rate is slower. At higher temperature (such as 1300°C), the recrystallized structure is consisted of grains. γ' particles retard migration of recrystallizing grain boundary. The depth of recrystallized layer exhibits a linear relationship with shot peening intensity. At 950°C, when the nominal stress is lower than 320MPa, the rupture life is not affected seriously, but is reduced when the nominal stress is 400MPa. Deep local recrystallization leads to surprised reduction of rupture life due to the stress concentration resulted from recrystallized volume.