Stress corrosion cracking of Fe-Ni-Cr-Mo, Ni-Cr-Mo and Ti alloys in 90 deg C acidic brine

摘要

Susceptibility to stress corrosion cracking (SCC) of candidate materials for the inner container of the multi-barrier nuclear waste package was evaluated by using wedge-loaded precracked double-cantilever-beam (DCB) specimens in deaerated acidic brine (pH at 2.70) at 90 deg C. Materials tested include Alloys 825, G-30, C-4, 625 and C-22; and Ti Grade-12. Duplicate specimen of each material was loaded at different initial stress intensity factor (K) values ranging between 23 and 46 ksi/in. Both metallography and compliance method were used to determine the final crack length. The final stress intensity for SCC (K(sup ISCC)) was computed from the measured final wedge load and the average crack length. The results indicate that in general, the final crack length measured by metallography and compliance was very close to each other, thus, providing very similar K(sup ISCC) values. While tests are still ongoing, the preliminary results suggest that, compared to other five alloys tested, Alloy 825 may exhibit the maximum tendency to SCC.