Corrosion fatigue crack growth behavior of alloy 52 M in high-temperature water

The corrosion fatigue (CF) crack growth behavior of Alloy 52 M in high temperature water was investigated in various water chemistries with dissolved oxygen (DO), dissolved hydrogen (DH) or Ar. The experimental results indicated that at higher load ratio (R), the CF crack growth rates (CGRs) in oxygenated water was slightly higher than Ar deaerated water, while under lower R, the relationship was reversed. Micro-characterization of the crack paths and fracture surfaces revealed that severe crack branching and localized inter-dendritic cracking occurred in oxygenated water, while relatively straight transgranular cracking developed in hydrogen and Ar deaerated water. Minor environmental enhancement of CGRs for Alloy 52 M weld metal was detected in oxygenated water but no environmental enhancement of CGRs was detected in hydrogen or Ar deaerated water.