Oxidation-creep interactions for an Hf-doped Ni-based superalloy with different wall thickness at 760 C

Stress rupture tests of an Hf-containing Ni-based superalloy with different wall thicknesses were carried out at 760 degrees C/691 Mpa using the RD-100 electronic machine. At the fracture edge, electron backscatter diffraction (EBSD) analysis showed that recrystallization (RS) occurred, and the width of RS increased with increasing sample thickness. The RS induced the intergranular corrosion cracking and accelerated the failure of the sample. At the interior of the substrate, voids were preferentially nucleated at the site of the Hf(Ta)C carbides, and the thinner sample suffered lighter creep damage than the thicker sample. Consequently, the thinner sample had a superior creep life.