title: Investigation of helium at a Y2Ti2O7nanocluster embedded in a BCC Fe matrix.
abstract: Nanostructured ferritic alloys (NFAs) are prime candidates for structural and first wall components of fission and fusion reactors. The main reason for this is their ability to effectively withstand high concentrations of the transmutation product helium. A high number density of oxide nanoclusters dispersed throughout a BCC Fe matrix act as trapping sites for helium and prevent its eventual delivery to high risk nucleation sites. The current study uses density functional theory to investigate the helium trapping mechanisms at the boundary between BCC iron and Y2Ti2O7, a common stoichiometry of the oxide nanoclusters in NFAs. The investigation is carried out on a structure matched oxide nanocluster that is embedded within a BCC Fe supercell. Investigation of the electronic structure and a mapping of the potential energy landscape reveals that the localized iono-covalent bonds present within the oxides create a potential energy-well within the metallically bonded BCC Fe matrix, so that trapping of helium at the oxide nanocluster is thermodynamically and kinetically favorable.
authors: Department of Materials Science and Engineering, Virginia Polytechnic Institute and State University, 635 Prices Fork Road, Blacksburg, VA 24060, USA. thomasd1@vt.edu.
authors: Thomas
authors: T
authors: Danielson
authors: Department of Mechanical Engineering, Virginia Polytechnic Institute and State University, 635 Prices Fork Road, Blacksburg, VA 24060, USA.
authors: Eric
authors: http://orcid.org/0000-0003-2560-0283
authors: E
authors: Tea
authors: Department of Materials Science and Engineering, Virginia Polytechnic Institute and State University, 635 Prices Fork Road, Blacksburg, VA 24060, USA. thomasd1@vt.edu and Department of Mechanical Engineering, Virginia Polytechnic Institute and State University, 635 Prices Fork Road, Blacksburg, VA 24060, USA.
authors: Celine
authors: C
authors: Hin