About this Abstract |
Meeting |
MS&T24: Materials Science & Technology
|
Symposium
|
Ceramic Materials for Nuclear Energy Systems
|
Presentation Title |
Atomic Scale Order in Swift Heavy Ion Irradiated MgAl2O4 Spinel Oxide |
Author(s) |
John M. Hirtz, Eric C. O'Quinn, Joerg C. Neuefeind, Matt Tucker, Arianna Minelli, Maik Lang |
On-Site Speaker (Planned) |
John M. Hirtz |
Abstract Scope |
Spinel (MgAl2O4) is highly resistant to radiation-induced amorphization making it attractive for nuclear technologies. Using neutron scattering techniques (total scattering and single crystal diffraction at the Spallation Neutron Source at Oak Ridge National Laboratory), we have, for the first time, analyzed both the long-range and short-range structure of swift heavy ion irradiated MgAl2O4 (2.2 GeV and 55 GeV Au ions). Samples were irradiated at the GSI Helmholtz Center to obtain sufficiently large sample volumes for neutron probes. Our data demonstrate that radiation-induced disordering in spinel is complex and heterogeneous across length scales. Single crystal diffraction shows a normal to inverse spinel transition, created during irradiation, which modifies the diffraction pattern by introducing new satellite peaks. Based on total scattering on powder samples these peaks can be explained by a re-arrangement of the Fd3 ̅m isometric structure to a P4122 tetragonal atomic configuration accompanied by an accumulation of cation Frenkel defects. |