title: Are nanoporous materials radiation resistant?
abstract: The key to perfect radiation endurance is perfect recovery. Since surfaces are perfect sinks for defects, a porous material with a high surface to volume ratio has the potential to be extremely radiation tolerant, provided it is morphologically stable in a radiation environment. Experiments and computer simulations on nanoscale gold foams reported here show the existence of a window in the parameter space where foams are radiation tolerant. We analyze these results in terms of a model for the irradiation response that quantitatively locates such window that appears to be the consequence of the combined effect of two length scales dependent on the irradiation conditions: (i) foams with ligament diameters below a minimum value display ligament melting and breaking, together with compaction increasing with dose (this value is typically ∼5 nm for primary knock on atoms (PKA) of ∼15 keV in Au), while (ii) foams with ligament diameters above a maximum value show bulk behavior, that is, damage accumulation (few hundred nanometers for the PKA's energy and dose rate used in this study). In between these dimensions, (i.e., ∼100 nm in Au), defect migration to the ligament surface happens faster than the time between cascades, ensuring radiation resistance for a given dose-rate. We conclude that foams can be tailored to become radiation tolerant.
authors.affiliation: CONICET & Instituto de Ciencias Básicas, Universidad Nacional de Cuyo, 5500 Mendoza, Argentina.
authors.forename: E M
authors.initials: EM
authors.lastname: Bringa
authors.forename: J D
authors.initials: JD
authors.lastname: Monk
authors.forename: A
authors.initials: A
authors.lastname: Caro
authors.forename: A
authors.initials: A
authors.lastname: Misra
authors.forename: L
authors.initials: L
authors.lastname: Zepeda-Ruiz
authors.forename: M
authors.initials: M
authors.lastname: Duchaineau
authors.forename: F
authors.initials: F
authors.lastname: Abraham
authors.forename: M
authors.initials: M
authors.lastname: Nastasi
authors.forename: S T
authors.initials: ST
authors.lastname: Picraux
authors.forename: Y Q
authors.initials: YQ
authors.lastname: Wang
authors.forename: D
authors.initials: D
authors.lastname: Farkas