Atomistic and experimental study of microstructural evolution in nanocrystalline iron subjected to irradiation

Fuente: arXiv
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Autori principali: Tolkachev, Ivan, Mason, Daniel R., Boleininger, Max, Ma, Pui-Wai, Long, Daniel, Connolly, Eamonn T., Thompson, Stephen P., Mizohata, Kenichiro, Hofmann, Felix
Natura: Preprint
Pubblicazione: 2025
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author Tolkachev, Ivan
Mason, Daniel R.
Boleininger, Max
Ma, Pui-Wai
Long, Daniel
Connolly, Eamonn T.
Thompson, Stephen P.
Mizohata, Kenichiro
Hofmann, Felix
author_facet Tolkachev, Ivan
Mason, Daniel R.
Boleininger, Max
Ma, Pui-Wai
Long, Daniel
Connolly, Eamonn T.
Thompson, Stephen P.
Mizohata, Kenichiro
Hofmann, Felix
contents Nanocrystalline materials have been proposed for use in future fusion reactors due to their high grain boundary density that may act as a sink for irradiation-induced defects. We use molecular dynamics to model collision cascades in nanocrystalline iron and compare the damage evolution to that observed in initially perfect, single crystalline iron. The nanocrystalline material is generated either by Voronoi tessellation or severe plastic shearing. Upon irradiation, the grains in nanocrystalline simulations coarsen, with all ultimately becoming single crystalline above 2 dpa. Above a damage dose of 1 dpa, nanocrystalline cells show a lower dislocation density and lower lattice swelling than their initially pristine counterparts. Experimental X-ray diffraction data is collected on nanocrystalline iron samples subjected to self-ion irradiation. Line profile analysis data agrees with the trends observed in the atomistic simulations, revealing the presence of an irradiation induced annealing process, with a clear reduction in micro-strain with increasing dose. We attempt to determine why some grains in our atomistic simulations grow, while others shrink, by creating a Toy Model that simulates volume exchange between grains based on different hypothesised exchange mechanisms. This suggests that irradiation-induced grain growth is consistent with random growth.
format Preprint
id arxiv_https___arxiv_org_abs_2505_21174
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Atomistic and experimental study of microstructural evolution in nanocrystalline iron subjected to irradiation
Tolkachev, Ivan
Mason, Daniel R.
Boleininger, Max
Ma, Pui-Wai
Long, Daniel
Connolly, Eamonn T.
Thompson, Stephen P.
Mizohata, Kenichiro
Hofmann, Felix
Materials Science
Nanocrystalline materials have been proposed for use in future fusion reactors due to their high grain boundary density that may act as a sink for irradiation-induced defects. We use molecular dynamics to model collision cascades in nanocrystalline iron and compare the damage evolution to that observed in initially perfect, single crystalline iron. The nanocrystalline material is generated either by Voronoi tessellation or severe plastic shearing. Upon irradiation, the grains in nanocrystalline simulations coarsen, with all ultimately becoming single crystalline above 2 dpa. Above a damage dose of 1 dpa, nanocrystalline cells show a lower dislocation density and lower lattice swelling than their initially pristine counterparts. Experimental X-ray diffraction data is collected on nanocrystalline iron samples subjected to self-ion irradiation. Line profile analysis data agrees with the trends observed in the atomistic simulations, revealing the presence of an irradiation induced annealing process, with a clear reduction in micro-strain with increasing dose. We attempt to determine why some grains in our atomistic simulations grow, while others shrink, by creating a Toy Model that simulates volume exchange between grains based on different hypothesised exchange mechanisms. This suggests that irradiation-induced grain growth is consistent with random growth.
title Atomistic and experimental study of microstructural evolution in nanocrystalline iron subjected to irradiation
topic Materials Science
url https://arxiv.org/abs/2505.21174