Abstract:
For bcc metals Fe and V, the most energetically favorable facet patterns of voids have been determined. Their sink strengths for self-point defects (vacancies and self-interstitial atoms) and the bias factors (relative difference in the sink strengths for self-interstitial atoms and vacancies) have been calculated. The calculations have been performed for the range of temperatures 293–1000 K and the void sizes 2.4–99 $a$ ($a$ is the lattice parameter) by an object kinetic Monte Carlo method. Elastic interaction of self-point defects in stable and saddle-point configurations (elastic dipoles) with the elastic fields of voids has been calculated by means of the anisotropic theory of elasticity. Elastic fields of voids have been calculated from atomic displacements from the positions of ideal crystalline lattice sites determined using the molecular statics method. The void bias factor depends on their size and temperature. The bias factor can take values comparable to screw dislocation bias factor values for small voids (sizes are less than several tens of $a$). The results obtained explain the experimentally observed features of radiation swelling of pure iron and vanadium irradiated with neutrons in fast reactors.
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