Radiation Damage in Metals and Alloys

Abstract

The article contains sections titled: Introduction Neutron–Nuclear Interactions Elastic Collisions Inelastic Collisions ( n , 2 n ) Reactions ( n ,γ) Reactions Atomic Displacements Kinchin‐Pease Model for Atom Displacements Modifications to the Kinchin–Pease Model Consideration of E d and E c in the Energy Balance (Assumptions #3 and #4) Realistic Energy Transfer Cross‐Sections (Assumption #5) Effects of Crystallinity (Assumption #6) Effect of Focusing and Channeling on Displacements Displacement Cross‐Section and Displacement Rates Displacement Rates Damage Cascade Primary Recoil Spectrum Cascade Volume and Damage Energy Stages of Cascade Development Behavior of Defects within the Cascade Computer Simulations of Radiation Damage Radiation‐Enhanced Diffusion Point Defect Concentrations under Irradiation Case (i): Low Temperature, Low Sink Density Case (ii): Low Temperature, Intermediate Sink Density Case (iii): Low Temperature, High Sink Density Case (iv): High Temperature Radiation‐Enhanced Diffusion (RED) Coefficient Radiation‐Induced Segregation (RIS) RIS in Concentrated Binary Alloys Effects of Interstitial Binding, Solute Size, Temperature, and Dose Rate RIS in Ternary Alloys Effect of Local Composition Changes on RIS Effect of Solutes on RIS RIS in Austenitic Alloys RIS in Ferritic Alloys Irradiated Microstructure Defect Clusters Cluster Mobility Loop Nucleation and Clustering Theory Loop Growth and Recovery Evolution of Interstitial Loop Microstructure Void Nucleation and Growth Bubble Growth Phase Stability Summary

Modelling Irradiation Effects in Metallic Materials using the Crystal Plasticity Theory

“…The amount of neutrons of a given energy flowing through the material can be characterised by their fluence Φ, which is equal to the number of neutrons dN penetrating the sphere having the cross section da: However, from the point of view of mechanics and materials science, the displacement per atom (dpa) [31] provides a better measure of the effects of irradiation on material, as it does not depend on the energetic spectrum of neutrons [32] and can be also applied to ions. In order to calculate dpa in the case of ion irradiation, the SRIM software [33] is commonly used.…”

“…However, when it comes to coupling the dislocation and defect terms, sometimes the sum of square roots (linear superposition) was used instead of the square root of sums. The issue of choosing the right superposition rule was thoroughly discussed in [18,32]. Also, the latent hardening introduced by means of interaction matrices was sometimes neglected.…”

Modeling Radiation Damage in Materials Relevant for Exploration and Settlement on the Moon

“…After the particle has been slowed down by the target's electrons, it undergoes nuclear elastic collisions, displacing atoms in the target (Primary Knock-on Atoms, PKAs) that constitute themselves additional projectiles (Figure 1(4)). The PKA collides with other atoms creating a cascade of collisions [97] (Figure 1(5)). Atomic displacements induce the creation of different types of point defects, such as vacancies and interstitials (Frenkel pairs) and defect clusters (Figure 1(6)) and happen on a much longer time scale (up to ns).…”

“…There is a large variety of methods used in condensed matter physics and materials science to study radiation effects in materials, each of them describing a particular aspect of the damage process. Figure 2 shows a schematic representation of the different time and length scales with the corresponding computational methods that can be applied to study different stages of radiation damage [97,121,122]. The very first stage, at the smallest time-length scale, is the electronic stopping regime.…”

Predicting the performance of tungsten in a fusion environment: a literature review

“…58 It has been used for multiple reasons: to separate effects due to direct displacement damage from those caused by transmutation and gas evolution, to accelerate materials testing to extremely high dpa levels, 59 and simply to avoid the additional cost and difficulty of neutron irradiation. 60 In order to best simulate the direct damage caused by fast neutrons, high-energy ions are used such that the main stopping force is due to direct collisions as opposed to electronic interactions, which dominate at low energies (< 1 MeV).…”