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The topic of the presentation is an example how to go beyond the standard molecular dynamics in the field of defects in materials science. Using Density Functional Theory, empirical potential and an improved eigenvector following like method we put into light and characterize new three dimensional periodic structure for self-interstitial clusters in body-centered-cubic metals, as opposed to the conventional and 50 years well established two dimensional loop morphology. The underlying crystal structure of new clusters corresponds to the C15 Laves phase. We demonstrate that in α-iron these C15 aggregates are highly stable and immobile and that they exhibit large antiferromagnetic moments [1]. They form directly in displacement cascades and they can grow by capturing self-interstitials. They thus constitute an important new element to account for when predicting the microstructural evolution of iron base materials under irradiation. 1. M.-C. Marinica, F. Willaime, J.-P. Crocombette, Phys. Rev. Lett., 108, 025501 (2012) |
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