High temperature moiré interferometry investigation of creep crack growth of inconel 783—environment and β-phase effects

The effect of β-phase and environment on creep crack growth behavior of Inconel 783, the newly developed low thermal expansion superalloy, was investigated using high temperature moiré interferometry. Results show that oxygen partial pressure plays an important role on the creep crack growth behaviors of the alloy. Stress assisted grain boundary oxygen (SAGBO) embrittlement is the principal mechanism of the environmental degradation of the alloy. β-Phase network along the grain boundaries of the alloy improves the resistance to creep crack growth by improving the ductility of the alloy and preventing the occurrence of SAGBO embrittlement.