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On the ductile-to-brittle transition behavior of martensitic alloys neutron irradiated to 26 dpa

Conference ·
OSTI ID:6650562
Charpy impact tests were conducted on specimens made of HT-9 and 9Cr-1Mo in various heat treatment conditions which were irradiated in EBR-II to 26 dpa at 390 to 500/sup 0/C. The results are compared with previous results on specimens irradiated to 13 dpa. HT-9 base metal irradiated at low temperatures showed a small additional increase in ductile brittle transition temperature and a decrease in upper shelf energy from 13 to 26 dpa. No fluence effect was observed in 9Cr-1Mo base metal. The 9Cr-1Mo weldment showed degraded DBTT but improved USE response compared to base metal, contrary to previous findings on HT-9. Significant differences were observed in HT-9 base metal between mill annealed material and normalized and tempered material. The highest DBTT for HT-9 alloys was 50/sup 0/C higher than for the worst case in 9Cr-1Mo alloys. Fractography and hardness measurements were also obtained. Significant differences in fracture appearance were observed in different product forms, although no dependence on fluence was observed. Failure was controlled by the preirradiation microstructure.
Research Organization:
Hanford Engineering Development Lab., Richland, WA (USA)
DOE Contract Number:
AC06-76FF02170
OSTI ID:
6650562
Report Number(s):
HEDL-SA-3535-FP; CONF-860605-42; ON: DE87005476
Country of Publication:
United States
Language:
English