Ductile fracture test methods used in evaluating neutron damage to AISI 316 H stainless steel

The evaluation of low (0.1 dpa) to intermediate (0.3 dpa to 1 dpa) neutron damage to AISI 316H stainless steel at temperature of 3500C and 5500C is studied. The test specimens are relatively small sized 3PB specimens not size grooved. Considering that about 100 specimens are programmed to be irradiated and about 50 reference specimens are to be tested as well, a few preliminary studies have been run on the specific problem of the fatigue precracking aiming at: obtaining reproducible crack fronts with similar rupture facies in the vicinity of the crack leading edge; obtaining crack fronts as straight as possible. This was thought to be an asset when determining the crack initiation point using the PD method. All test are run using computer technique to determine the J integral, Jsub(ic) at initiation and a final Jsub(f) corresponding to some crack growth, measured by heat-tinting the specimens