title: In situ study of defect migration kinetics in nanoporous Ag with enhanced radiation tolerance.
abstract: Defect sinks, such as grain boundaries and phase boundaries, have been widely accepted to improve the irradiation resistance of metallic materials. However, free surface, an ideal defect sink, has received little attention in bulk materials as surface-to-volume ratio is typically low. Here by using in situ Kr ion irradiation technique in a transmission electron microscope, we show that nanoporous (NP) Ag has enhanced radiation tolerance. Besides direct evidence of free surface induced frequent removal of various types of defect clusters, we determined, for the first time, the global and instantaneous diffusivity of defect clusters in both coarse-grained (CG) and NP Ag. Opposite to conventional wisdom, both types of diffusivities are lower in NP Ag. Such a surprise is largely related to the reduced interaction energy between isolated defect clusters in NP Ag. Determination of kinetics of defect clusters is essential to understand and model their migration and clustering in irradiated materials.
authors.affiliation: 1] Department of Materials Science and Engineering, Texas A&M University, College Station, TX 77843 [2] Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM, 87545.
authors.forename: C
authors.initials: C
authors.lastname: Sun
authors.affiliation: Department of Materials Science and Engineering, Texas A&M University, College Station, TX 77843.
authors.forename: D
authors.initials: D
authors.lastname: Bufford
authors.affiliation: Department of Materials Science and Engineering, Texas A&M University, College Station, TX 77843.
authors.forename: Y
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Materials Science Division, Argonne National Laboratory, Argonne, IL 60439, USA.
authors.forename: M A
authors.initials: MA
authors.lastname: Kirk
authors.affiliation: Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM, 87545.
authors.forename: Y Q
authors.initials: YQ
authors.lastname: Wang
authors.affiliation: Nuclear Engineering Division, Argonne National Laboratory, Argonne, IL 60439, USA.
authors.forename: M
authors.initials: M
authors.lastname: Li
authors.affiliation: 1] Department of Materials Science and Engineering, Texas A&M University, College Station, TX 77843 [2] Department of Electrical and Computer Engineering, Texas A&M University, College Station, TX 77843.
authors.forename: H
authors.initials: H
authors.lastname: Wang
authors.affiliation: Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM, 87545.
authors.forename: S A
authors.initials: SA
authors.lastname: Maloy
authors.affiliation: 1] Department of Materials Science and Engineering, Texas A&M University, College Station, TX 77843 [2] Department of Mechanical Engineering, Texas A&M University, College Station, TX 77843.
authors.forename: X
authors.initials: X
authors.lastname: Zhang