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.

Mechanism of Radiation Damage Reduction in Equiatomic Multicomponent Single Phase Alloys

“…This has motivated an intense ongoing search for new classes of materials with improved radiation hardness. New materials, shown to have high radiation tolerance include nanocrystalline materials [14][15][16], multilayered nanomaterials [17], and nanofoams [18,19]. Although all of these are promising for some applications, the high fraction of surface or interface, which are thermodynamically unstable, makes nanostructures in general unreliable for long operational times at elevated temperatures.…”

Confinement Effects of Ion Tracks in Ultrathin Polymer Films

“…Recently, with the growing use of nanostructured systems in various types of technological devices, the understanding of specificities in energy deposition and damage production by radiation in matter at the nanoscale has become a critical issue. Unique effects of energetic ions on nanoscale systems have already been reported and successfully applied to engineering of materials [10][11][12][13]. Nevertheless, very little has been reported so far on a direct comparison of radiation effects of heavy ions in a material at bulk and spatially confined conditions.…”

Effect of Grain Boundary Stresses on Sink Strength

“…In these materials, nanoprecipitate-matrix interfaces provide effective sinks for transmutation products and irradiation-induced defects. [5] A recent study [6] has shown that enhanced radiation resistance can also be exhibited by nanoporous materials, since free surfaces can act as unsaturable defect sinks. In addition, a number of experimental [7,8] and simulation [9][10][11][12] studies have shown that bulk nanocrystalline (nc) materials * Corresponding authors.…”