Effect of prior-deformation on the stability of the intermetallic precipitate in Zircaloy-2
- GE Nuclear Energy, Pleasanton, CA (United States). Vallecitos Nuclear Center
Zircaloy-2 is commonly used for cladding tubes in boiling water reactors (BWR`s). The high fluence of neutron irradiation causes microstructural changes which affect corrosion, mechanical properties and irradiation growth. Here, both stress-relieved (SR) and recrystallized (RX) samples irradiated near 300 C to fluences between 1 and 9 {times} 10{sup 21} n/cm{sup 2} (E>1MeV) were examined using analytical scanning transmission electron microscopy (STEM). The aim was to extend their knowledge or irradiation effects on microstructure by examining the effect of prior-cold-work on the dissolution of intermetallic precipitates in Zircaloy-2. Resulting from prior mechanical deformation and fast neutron irradiation, SR samples contain a high density of -component, mixed line dislocations and ``black dot`` damage. On the other hand, RX samples contain mostly ``black dot`` damage. Pure -dislocations are detected in the high fluence samples in RX materials. For identical irradiation conditions, different degrees of amorphization and dissolution are observed in RX and SR samples. Also, preferential diffusion of solute is observed to occur along -dislocations. These results are discussed in terms of possible interactions between irradiation produced defects, precipitates and solutes.
- OSTI ID:
- 99438
- Report Number(s):
- CONF-941144--; ISBN 1-55899-275-8
- Country of Publication:
- United States
- Language:
- English
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