Quantatitive fractographic details of low alloy pressure vessel steels fatigued in light water reactor environments

The present paper attempts to describe the related environment assisted crack, EAC, growth and the quantitative fractography of the fatigue fracture surfaces observed during some fatigue tests on low alloy pressure vessel steels in high temperature aqueous environments which essentially simulated light water reactor, LWR, waters. It has been demonstrated that when EAC growth occurred it was associated with the development of static failure facets upon the fatigue fracture surfaces. In the present material-environment system the predominant static failure mode was fan-shaped, cleavage like, growth while a few instances of microvoid coalescence were also recorded. Indeed a strong relationship between the level of EAC growth and the area fraction of fan-shaped growth measured upon the fatigue fracture surface was clearly demonstrated