|About this Abstract
||2017 TMS Annual Meeting & Exhibition
||Gamma (FCC)/Gamma-Prime (L12) Co-Based Superalloys II
||Planar Defect Formation in the γ' Phase during High Temperature Creep in Single Crystal CoNi-base Superalloys
||Yolita Maria Eggeler, Julian Müller, Mike S. Titus, Akane Suzuki, Tresa Pollock, Erdmann Spiecker
|On-Site Speaker (Planned)
The structure and formation mechanisms of extended planar defects in the γ/γꞌ microstructure of tensile creep deformed CoNi-base single crystal superalloys have been analyzed in detail using complementary electron microscopy methods. A total crystallographic slip of 1/2[-1-12] leaves superlattice intrinsic stacking faults (SISF) embedded in antiphase boundaries (APB), which are separated by a 1/6[-1-12] dislocation loop contained inside of the γꞌ precipitates. A characteristic APB/SISF/APB configuration along contiguous γꞌ precipitates remains after dislocation slip. Energy dispersive X-ray spectroscopy (EDXS) provides evidence for pronounced segregation at both types of planar defects. This newly-identified deformation mechanism emphasizes the important role that planar defect energies and solute segregation have in determining the active deformation mode. Methods for characterizing this complex deformation mode will be presented, and implications for alloy design will be discussed.