Effects of Temperature and Secondary Orientations on the Deformation Behavior of Single-Crystal Superalloys

The tensile behavior of single-crystal superalloys was investigated at room temperature (RT) and 850 degrees C, focusing on various secondary orientations. Transmission electron microscopy (TEM) and quasi in situ electron backscatter diffraction (EBSD) were employed to study the deformation mechanisms across length scales. Deformation at 850 degrees C enhanced the tensile ductility of the samples, evidenced by the more uniform coverage of dislocations across the gamma and gamma ' phases, and the fracture mode switched from pure cleavage at room temperature to mixed mode due to accelerated void growth. The influence of secondary orientations on mechanical properties is insignificant at room temperature. However, the ductility of the different secondary orientation samples shows significant variations at 850 degrees C, among which the one with [001] rotated 37 degrees demonstrated superior ductility compared to others.