Article ID Journal Published Year Pages File Type
1573706 Materials Science and Engineering: A 2016 8 Pages PDF
Abstract
Nanostructured ferritic alloys are dispersion strengthened and imbued with remarkable neutron irradiation damage tolerance by an ultrahigh density of nano-oxide precipitates that must remain stable under prolonged high-temperature service. Here, previously reported long-time and high-temperature thermal aging data is used to derive a simple, but physically based and quantitatively predictive nano-oxide coarsening model using least square fits to equations representing different underlying mechanisms. A dislocation pipe diffusion model adequately fit the data with a dislocation-detachment climb mechanism providing the best fit. This model is consistent with microstructural observations and recently reported thermo-kinetic nano-oxide nucleation, growth and coarsening simulations that rationalize the underlying physics of coarsening. It is predicted that the nano-oxides will remain fully stable up to 900 °C. This remarkable coarsening resistance is due to the extremely low matrix solubility and diffusion rate of Y in equilibrium with Y2Ti2O7 that activates lower resistant paths along dislocations.
Related Topics
Physical Sciences and Engineering Materials Science Materials Science (General)
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