D. Nguyen-Manh S. L. Dudarev
We derive a model tight-binding many-body d -electron Stoner Hamiltonian for FeCr binary alloys and investigate the sensitivity of its mean-field solutions to the choice of hopping integrals and the Stoner exchange parameters. By applying the local charge-neutrality condition within a self-consistent treatment we show that the negative enthalpy-of-…
PublishedS. Chiesa P. M. Derlet S. L. Dudarev
The stability of interstitial defect and dislocation structures in bcc Fe as a function of temperature is believed to play a crucial role in determining defect evolution under irradiation conditions. The vibrational properties of defects constitute one contribution to the corresponding energetics and much work has been done within the harmonic appr…
PublishedPui-Wai Ma C. H. Woo S. L. Dudarev
Finite temperature magnetic properties of iron thin films are investigated, up to ferro/paramagnetic transition. The coupled dynamics of atoms and magnetic moments is treated using large-scale spin-lattice dynamics (SLD) simulations. A comprehensive study of surface and bulk magnetic properties is conducted, to investigate their dependences on temp…
PublishedPui-Wai Ma C. H. Woo S. L. Dudarev
We develop a Spin-Lattice Dynamics (SLD) simulation model for ferromagnetic iron where atoms are treated as classical particles with spins. The atoms interact via many-body forces as well as via spin-orientation-dependent forces of the Heisenberg form. The coupling between the lattice and the spin degrees of freedom is described by a coordinate-dep…
PublishedP. M. Derlet D. Nguyen-Manh S. L. Dudarev
We investigate the structure and mobility of single self-interstitial atom and vacancy defects in bodycentered- cubic transition metals forming groups 5B vanadium, niobium, and tantalum and 6B chromium, molybdenum, and tungsten of the Periodic Table. Density-functional calculations show that in all these metals the axially symmetric 111 self-inters…
PublishedM. Yu. Lavrentiev R. Drautz D. Nguyen-Manh T. P. C. Klaver S. L. Dudarev
Iron-chromium alloys are characterized by a complex phase diagram, by the small negative enthalpy of mixing at low Cr concentrations in the bcc -phase of Fe, and by the inversion of the short-range order parameter. We present Monte Carlo simulations of the binary Fe-Cr alloy based on the cluster expansion approximation for the enthalpy of the syste…
PublishedD. Nguyen-Manh A. P. Horsfield S. L. Dudarev
We present an investigation of systematic trends for the self-interstitial atom SIA defect behavior in body-centered cubic bcc transition metals using density-functional calculations. In all the nonmagnetic bcc metals the most stable SIA defect configuration has the 111 symmetry. Metals in group 5B of the periodic table V, Nb, Ta have significantly…
PublishedS. L. Dudarev A. A. Semenov C. H. Woo
We investigate the dynamics of nucleation and the growth of voids in an irradiated material in the presence of a spatially heterogeneous dislocation microstructure. We find that, due to the sensitivity of the void nucleation rate to the local vacancy supersaturation, voids nucleate and grow almost exclusively in the regions where the density of dis…
PublishedS. L. Dudarev A. A. Semenov C. H. Woo
We found that by assuming that the density of dislocations in an irradiated material varies as a function of the distance to grain boundaries and that mobile interstitial defect clusters perform three-dimensional diffusional motion it is possible to achieve significantly better agreement with experimental observations of profiles of heterogeneous v…
Published