Principles of radiation-induced damage to metals
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The core mechanism of radiation-induced damage to metals is the interaction between high-energy particles and the metal lattice, which leads to a gradual development of microscopic defects that result in a deterioration of macroscopic properties. The specific mechanisms can be divided into the following key steps: displacement of atomic sites. High-energy particles such as neutrons and protons collide with the atoms in the metal lattice; when the energy transferred exceeds the displacement threshold of about 25 eV, the target atom is displaced from its equilibrium position, becoming a primary ejected atom, while a vacancy is left in its place, thus forming the most basic Frenkel defect pair. Cascading collisions and localized damage: The initially ejected atoms, carrying high energy, continue to collide with other lattice atoms, triggering a chain reaction that generates a large number of vacancies and interstitial atoms within a very small volume; ultimately, this results in a displacement peak with a vacancy-rich core surrounded by interstitial atoms on the edges. Defect evolution and macroscopic effects: The generated point defects will further migrate and aggregate, gradually forming secondary defects such as dislocation loops, voids, and stacking fault tetrahedra ； Under the action of the defect well bias mechanism, metals exhibit macroscopic property changes such as irradiation swelling, hardening, and embrittlement; simultaneously, elements such as hydrogen and helium generated by nuclear transmutation form bubbles, further exacerbating material damage.
It is written very professionally, clearly explaining the evolutionary process of radiation damage from a microscopic to a macroscopic level. I have also read some materials on nuclear materials before, and I would like to add that in practical engineering applications, more attention is usually paid to the swelling and embrittlement of metals after irradiation. For example, 6061 aluminum expands in volume after being irradiated in a reactor, which leads to deformation, and there is also the issue of irradiation creep in the cladding materials of fast reactors. Has the original poster come into actual contact with any specific cases of damage under certain materials or operating conditions? We can discuss together the countermeasures in practical applications, such as adjusting alloy composition or optimizing heat treatment processes.