Radiation tolerance of ceramics - Insights from atomistic simulation of damage accumulation in pyrochlores
- Pacific Northwest National Laboratory (PNNL)
- ORNL
- Curtin University of Technology, Perth, Australia
We have used molecular dynamics simulations to investigate the effects of radiation damage accumulation in two pyrochlore-structured ceramics, namely Gd{sub 2}Ti{sub 2}O{sub 7} and Gd{sub 2}Zr{sub 2}O{sub 7}. It is well known from experiment that the titanate is susceptible to radiation-induced amorphization, while the zirconate does not go amorphous under prolonged irradiation. Our simulations show that cation Frenkel pair accumulation eventually leads to amorphization of Gd{sub 2}Ti{sub 2}O{sub 7}, and both anion disorder and cation disorder occur during damage accumulation. Amorphization in Gd{sub 2}Ti{sub 2}O{sub 7} is accompanied by a density decrease of about 12.7% and a decrease of about 50% in the elastic modulus. In Gd{sub 2}Zr{sub 2}O{sub 7}, amorphization does not occur, because the residual damage introduced by radiation is not sufficiently energetic to destabilize the crystal structure and drive the material amorphous. Subtle differences in damage accumulation and annealing between the two pyrochlores lead to drastically different radiation response as the damage accumulates.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- DE-AC05-00OR22725
- OSTI ID:
- 992097
- Journal Information:
- Energy & Environmental Science, Vol. 3, Issue 10; ISSN 1754-5692
- Country of Publication:
- United States
- Language:
- English
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