Influence of Notch on Creep Properties of GH3536 Nickel-Based Superalloy

Abstract:

High-temperature (750 oC) creep tests of smooth and notched specimens were performed, and the creep properties of GH3536 nickel-base superalloys were investigated under the tension loading of 160 MPa, 200 MPa and 240 MPa. The creep fracture mechanism was revealed with the scanning electron microscopy (SEM) analysis of the fracture surface and finite element analysis (FEM) of the stress distributions. The results show that notches reduce both of the creep deformation and the creep rate compared with the smooth specimen. The FEM analysis indicates that the axial stress redistribution and relaxation in the notch root benefit the creep properties of the specimen and lead to longer creep life. The SEM analysis shows that although the surface morphology is different, the growth and accumulation of microspores are the main factors of creep fracture for both smooth and notched specimens.