Non-random walk diffusion enhances the sink strength of semicoherent interfaces

Abstract

Clean, safe and economical nuclear energy requires new materials capable of withstanding severe radiation damage. One strategy of imparting radiation resistance to solids is to incorporate into them a high density of solid-phase interfaces capable of absorbing and annihilating radiation-induced defects. Here we show that elastic interactions between point defects and semicoherent interfaces lead to a marked enhancement in interface sink strength. Our conclusions stem from simulations that integrate first principles, object kinetic Monte Carlo and anisotropic elasticity calculations. Surprisingly, the enhancement in sink strength is not due primarily to increased thermodynamic driving forces, but rather to reduced defect migration barriers, which induce a preferential drift of defects towards interfaces. The sink strength enhancement is highly sensitive to the detailed character of interfacial stresses, suggesting that ‘super-sink' interfaces may be designed by optimizing interface stress fields. Such interfaces may be used to create materials with unprecedented resistance to radiation-induced damage.

First-principles calculation of the elastic dipole tensor of a point defect: Application to hydrogen inα-zirconium

“…This is particularly clear with small self-interstitial clusters where the distinction between host and defect atoms is often untenable. Since in general the distinction between host and defect atoms cannot be maintained the stress method is based on the following expression [9,[36][37][38]:…”

Energetics of vacancy segregation to [100] symmetric tilt grain boundaries in bcc tungsten

“…For example, Tschopp, Solanki and coworkers have performed extensive atomistic simulations to investigate the effects of GB character on the formation energetics of point defects, such as vacancy922232430, self-interstitial9, hydrogen2526, helium2627, carbon2628 and various other impurities2326. Aiming to mitigate radiation damage, Uberuaga, Demkowicz and coworkers have conducted massive multiscale simulations193132333435363738 to understand the effects of interface structure on point defect segregation, defect mobility, defect recombination and GB sink efficiency. Jiang et al 29.…”

Imeall: A computational framework for the calculation of the atomistic properties of grain boundaries

“…1 These 5 degrees of freedom constitute thermodynamic variables for the system and specify the boundary conditions far removed from the boundary [8]. To generate a boundary, two identical crystals, which we may here differentiate by referring to them as the 'red crystal' and the 'blue crystal' (see Fig.…”

“…All red crystal atoms located below the boundary plane and all blue crystal atoms located above the boundary plane are at this point removed. We will refer to the choice of orientation axis, misorientation angle, 1 In the case of enantiomorphic crystals the chirality of the crystal at the interface can constitute a 6th macroscopic degree of freedom. Fig.…”

“…Evaluating several properties of significant engineering interest requires access to the atomistic structures of grain boundaries. These include, but are by no means limited to, the diffusivity of impurities at grain boundary interfaces [1], the segregation energies of impurities to interfaces [2], and the interaction and slip transmission of dislocations across boundaries [3,4]. While a number of systematic investigations of grain boundary structures have been performed, see Refs.…”