title: Direct Observation of Defect Range and Evolution in Ion-Irradiated Single Crystalline Ni and Ni Binary Alloys.
abstract: Energetic ions have been widely used to evaluate the irradiation tolerance of structural materials for nuclear power applications and to modify material properties. It is important to understand the defect production, annihilation and migration mechanisms during and after collision cascades. In this study, single crystalline pure nickel metal and single-phase concentrated solid solution alloys of 50%Ni50%Co (NiCo) and 50%Ni50%Fe (NiFe) without apparent preexisting defect sinks were employed to study defect dynamics under ion irradiation. Both cross-sectional transmission electron microscopy characterization (TEM) and Rutherford backscattering spectrometry channeling (RBS-C) spectra show that the range of radiation-induced defect clusters far exceed the theoretically predicted depth in all materials after high-dose irradiation. Defects in nickel migrate faster than in NiCo and NiFe. Both vacancy-type stacking fault tetrahedra (SFT) and interstitial loops coexist in the same region, which is consistent with molecular dynamics simulations. Kinetic activation relaxation technique (k-ART) simulations for nickel showed that small vacancy clusters, such as di-vacancies and tri-vacancies, created by collision cascades are highly mobile, even at room temperature. The slower migration of defects in the alloy along with more localized energy dissipation of the displacement cascade may lead to enhanced radiation tolerance.
authors.affiliation: Department of Nuclear Engineering and Radiological Science, University of Michigan, Ann Arbor, MI 48109-2104, USA.
authors.forename: Chenyang
authors.initials: C
authors.lastname: Lu
authors.affiliation: Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.|Department of Materials Science &Engineering, University of Tennessee, Knoxville, TN 37996, USA.
authors.forename: Ke
authors.initials: K
authors.lastname: Jin
authors.affiliation: Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
authors.forename: Laurent K
authors.initials: LK
authors.lastname: Béland
authors.affiliation: Department of Nuclear Engineering and Radiological Science, University of Michigan, Ann Arbor, MI 48109-2104, USA.
authors.forename: Feifei
authors.initials: F
authors.lastname: Zhang
authors.affiliation: Department of Nuclear Engineering and Radiological Science, University of Michigan, Ann Arbor, MI 48109-2104, USA.
authors.forename: Taini
authors.initials: T
authors.lastname: Yang
authors.affiliation: Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.|School of Materials, The University of Manchester, Manchester M13 9PL, UK.
authors.forename: Liang
authors.initials: L
authors.lastname: Qiao
authors.affiliation: Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
authors.forename: Yanwen
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
authors.forename: Hongbin
authors.initials: H
authors.lastname: Bei
authors.affiliation: Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
authors.forename: Hans M
authors.initials: HM
authors.lastname: Christen
authors.affiliation: Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
authors.forename: Roger E
authors.initials: RE
authors.lastname: Stoller
authors.affiliation: Department of Nuclear Engineering and Radiological Science, University of Michigan, Ann Arbor, MI 48109-2104, USA.
authors.forename: Lumin
authors.initials: L
authors.lastname: Wang
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