Microstructure of a heavily irradiated metal exposed to a spectrum of atomic recoils

TL;DR

This paper models the microstructure evolution in heavily irradiated metals at low temperatures, revealing how defect content depends on ion energy and dose, with low energy ions causing more damage.

Contribution

It introduces a new athermal model for microstructure evolution that accounts for defect production and recombination based on ion energy spectrum.

Findings

Low energy ions produce more damage than high energy ions.

Defect content depends on the spectrum of primary knock-on atom energies.

Microstructure properties vary with ion energy and dose.

Abstract

At temperatures below the onset of vacancy migration, metals exposed to energetic ions develop dynamically fluctuating steady-state microstructures. Statistical properties of these microstructures in the asymptotic high exposure limit are not universal and vary depending on the energy and mass of the incident ions. We develop a model for the microstructure of an ion-irradiated metal under athermal conditions, where internal stress fluctuations dominate the kinetics of structural evolution. The balance between defect production and recombination depends sensitively not only on the total exposure to irradiation, defined by the dose, but also on the energy of the incident particles. The model predicts the defect content in the high dose limit as an integral of the spectrum of primary knock-on atom energies, with the finding that low energy ions produce a significantly higher amount of damage than high energy ions.