Physics of Metals and Metallography (v.114, #13)

The review is devoted to the description of fundamental properties of Pu based on ab initio and classical molecular-dynamics microscopic theories which could be linked to each other. The details of various methods such as LSDA, LDA + U, LDA + U + SO, LDA + DMFT, CMD, MEAM, and GEAM are presented. The results obtained in the framework of these approaches are discussed.
Keywords: plutonium; electronic structure; LDA; LDA + U; LDA + U + SO; LDA + DMFT; Hubbard bands; quasiparticle peak; molecular dynamics; Pu aging; helium bubbles; radiation-damage cascades

Phase and structural transformations in U and U-Nb alloy upon severe deformation and heat treatments by Yu. N. Zuev; V. V. Sagaradze; N. L. Pecherkina; I. I. Kabanova; I. L. Svyatov; S. V. Bondarchuk; D. V. Belyaev (1123-1154).
Transmission electron microscopy was used to analyze the twin and dislocation structure of samples of commercial uranium in the initial (undeformed) state and after severe deformation using explosive loading by plane and spherical waves of various intensity. It has been shown that an increase in the intensity of explosive loading by a plane wave leads, first, to an increase in the density of randomly distributed dislocations and twins and, then, to the development of polygonization processes with the formation of a subgrain structure of the α phase. Crystallographic analysis of the initial and deformation-induced twins in uranium has shown the presence of predominantly {130} twins of mixed type and, in singular cases, {172} and {176} twins of the second kind. It has been established that the retained spherical shells have a distinctly pronounced zonal structure, which contains information on the forward and reverse martensitic phase transformations of uranium (α ↔ β(γ) ↔ L, etc.) that occur under shock-wave loading by spherical waves. Conditions are determined for the manifestation of structural heredity in the U-6 wt % Nb alloy with recovery of the size and shape of grains of the initial high-temperature γ phase during the forward γ → α″ martensitic transformation upon cooling and during reverse α″ → γ transformation upon heating. Elimination of the structural heredity with significant grain refinement of the high-temperature γ phase occurs in the process of repeated quenching from 700°C after one type of preliminary treatments (cold deformation of α″ martensite, recrystallization of the deformed α″ phase, high-temperature aging of the initial α″ martensite, and eutectoid decomposition).
Keywords: uranium; U-Nb alloy; shock-wave loading; deformation; martensite transformation; grain refinement; twinning; structure heredity

Magnetic peculiarities of plutonium and compounds by F. A. Kassan-Ogly; A. V. Korolev; V. V. Ustinov; Yu. N. Zuev; V. E. Arkhipov (1155-1181).
The problems concerning the peculiarities of plutonium crystal structures, their distinguishing features from the structures of common metals are discussed in the paper. They are found to be in close interdependence with the intricate problem of localized magnetic moments and magnetic ordering in plutonium and its numerous compounds. Multifarious physical models suggested for determining the nature and origins of these peculiar features, based on the well-known concepts and approaches and also on novel very original and exotic ideas, are considered. The detailed comparative analysis of experimental achievements and numerous papers in various versions of numerical computations in “the first principles (ab initio)” approach is carried out. Some new effects recently discovered and not as yet comprehended are regarded as well.
Keywords: plutonium; fundamental properties; self-irradiation; allotropes; localized magnetic moment