Stress corrosion cracking of high energy proton-irradiated stainless steels
- Univ. of Michigan, Ann Arbor, MI (United States)
- GE Corporate R&D Center, Schenectady, NY (United States)
The role of grain boundary phosphorus and the grain boundary redistribution of nickel, chromium, and iron in irradiation assisted stress corrosion cracking (IASCC) has been investigated using an ultra high purity (UHP) type 304 stainless steel alloy and an UHP alloy doped with either phosphorus or sulfur. Grain boundary compositions were determined using Auger spectroscopy, and both thermal and radiation-induced phosphorus segregation occurred in the UHP+P specimens, to 5.7 at% and 8.4 at%, respectively. Sulfur did not segregate to appreciable levels in the UHP+S specimens. After proton irradiation at 400{degrees}C to 1 dpa, the chromium grain boundary concentrations dropped by 3.5 at% in the HP alloy and 5.0 at% in the UHP+P and UHP+S alloys. Intergranular surface cracking in CERT tests performed at 288{degrees}C, in 0.25 {mu}S/cm or 0.5 {mu}S/cm water containing 2 ppm O{sub 2} occurred only in the irradiated region of all the specimens. The greatest amount of IG surface cracking occurred in the UHP alloy, but the UHP+S specimen failed at a significantly lower elongation, as the crack propagated very rapidly to specimen failure. The UHP+P alloy failed at the greatest elongation, and showed a low amount of IG cracking. This suggests that phosphorus segregation is not deleterious and perhaps beneficial, while chromium depletion may be deleterious in the IASCC of proton irradiated type 304 stainless steel.
- DOE Contract Number:
- FG07-88ER12825
- OSTI ID:
- 48115
- Report Number(s):
- CONF-910808--
- Country of Publication:
- United States
- Language:
- English
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