Abstract
Stress relaxation behavior was investigated for the nanoclusters/ dispersoids-strengthened steels including the nanostructured ferritic alloy 14YWT (SM10), oxide-dispersion strengthened (ODS) Eurofer97, and commercial ODS steel PM2000. The stress relaxation tests were carried out at high temperatures ranging from 600 to 1000°C. Overall, the relaxation rates of 14YWT and ODS-Eurofer97 were lower than that of PM2000. To analyze the strain rate sensitivity of the alloys, the load drop-time curves were converted to the stress-strain rate curves. In the log-log plots of these curves, no significant change in slope was observed in the strain rate range of 2 × 10 -5-1 × 10 -3s -1. At 600°C, 14YWT and ODS-Eurofer97 have similar activation values of ∼50b 3 while PM2000 has ∼100b 3. Above 700°C, the differences of the activation energy among alloys become more noticeable with increasing temperature. The activation energies of the three alloys were derived and compared. The rate-controlling mechanisms in the stress relaxation of the three nanoclusters/dispersoids-hardened alloys include dislocation glide and climb, and further study is necessary to clarify detailed contributing mechanisms.
Original language | English |
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Pages (from-to) | 147-155 |
Number of pages | 9 |
Journal | Journal of Nuclear Materials |
Volume | 425 |
Issue number | 1-3 |
DOIs | |
State | Published - Jun 2012 |
Funding
This research was sponsored by the in-house research project of the Korea Institute of Materials Science and 2009 Scientist & Engineers Exchange Program supported by the Ministry of Knowledge Economy of the Republic of Korea, which is under IAN: 16B642601 with the US Department of Energy. It was also sponsored by US Department of Energy, Office of Nuclear Energy under Contract DE-AC05-00OR22725 with UT-Battelle, LLC.