Creep anisotropy dominated by orientation rotation in Ni-based single crystal superalloys at 750 °C/750 MPa

Abstract

The creep anisotropy of Ni-based single crystal superalloys was studied at 750 °C/750 MPa. Transmission electron microscopy (TEM) observations showed that stacking faults and micro-twins were the typical dislocation configurations, which all originated from the activity of {111} 〈112〉 slip systems. Then, the orientation rotation caused by the activity of the main {111} 〈112〉 slip system would accelerate the specimen fracturing in shear fracture mode. Furthermore, the orientation rotation would dominate the creep anisotropy. The orientation rotation would occur during the entire creep process, the greater the degree of rotation, the more severe the asynchrony of rotation, which would result in nonuniform deformation and local stress concentration, and exacerbate the failure of the specimen.