Fundamental radiation effects parameters in metals and ceramics [electronic resource].
- Oak Ridge, Tenn. : Oak Ridge National Laboratory, 1998.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
- Physical Description:
- pages 291 : digital, PDF file
- Additional Creators:
- Oak Ridge National Laboratory
United States. Department of Energy. Office of Scientific and Technical Information
- Useful information on defect production and migration can be obtained from examination of the fluence-dependent defect densities in irradiated materials, particularly when a transition from linear to sublinear accumulation is observed. Further work is needed on several intriguing reported radiation effects in metals. The supralinear defect cluster accumulation regime in thin foil irradiated metals needs further experimental confirmation, and the physical mechanisms responsible for its presence need to be established. Radiation hardening and the associated reduction in strain hardening capacity in FCC metals is a serious concern for structural materials. In general, the loss of strain hardening capacity is associated with dislocation channeling, which occurs when a high density of small defect clusters are produced (stainless steel irradiated near room temperature is a notable exception). Detailed investigations of the effect of defect cluster density and other physical parameters such as stacking fault energy on dislocation channeling are needed. Although it is clearly established that radiation hardening depends on the grain size (radiation-modified Hall-Petch effect), further work is needed to identify the physical mechanisms. In addition, there is a need for improved hardening superposition models when a range of different obstacle strengths are present. Due to a lack of information on point defect diffusivities and the increased complexity of radiation effects in ceramics compared to metals, many fundamental radiation effects parameters in ceramics have yet to be determined. Optical spectroscopy data suggest that the oxygen monovacancy and freely migrating interstitial fraction in fission neutron irradiated MgO and Al₂O₃ are ∼10% of the NRT displacement value. Ionization induced diffusion can strongly influence microstructural evolution in ceramics. Therefore, fundamental data on ceramics obtained from highly ionizing radiation sources such as electrons must be treated with appropriate caution to determine if it is influenced by ionization induced diffusion effects.
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