Stacking faulted P phase in a grit-blasted Ni-based single-crystal superalloy after thermal exposure

Abstract

In the present work, direct and detailed investigation was carried out with respect to the precipitation in the grit-blasted single-crystal superalloy of DD6 after thermal exposure at 1100°C for 8 h. The precipitation was confirmed to be an orthorhombic topologically close-packed phase of P. In the phase, abundant atomic stacking faults were clearly revealed by bright field transmission electron microscope imaging and high-resolution HAADF imaging. Furthermore, statistical analysis for the 42 P phase particles observed by electron backscattered diffraction revealed that they had a mean size of 0.21 µm and volume percentage of 0.172% in the recrystallised region. The orientation distribution was essentially random besides very weak textures of {511}<0-32> and {921}<0-15>.