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No abstract available

[en] The effect of Barium (Ba) addition (0, 0.05, 0.15, 0.5 wt. pct) on the microstructure and mechanical properties of an Al-7Si alloy was studied. Differential scanning calorimetry was employed to analyze the nucleation behavior of eutectic Si. Transmission electron microscopy was used to clarify growth mechanism of eutectic Si. The result indicates that the addition of 0.15 wt. pct Ba modifies the morphology of eutectic Si from coarse flake-like to fine fibrous, which dramatically improves the ultimate tensile strength and elongation. However, Ba addition (≥ 0.15 wt. pct) induces the formation of coarse blocky Ba containing phase (i.e. Al₂Si₂Ba phase) and porosity increment, and resultantly has a deleterious effect on the ductility. Thermal analysis reveals that Ba addition suppresses the nucleation of eutectic Si due to the formation of Ba₃P₂ phase. Significant multiply Si twins with high density was observed in the Ba containing alloy, which provides an experimentally support to the impurity-induced twinning growth mechanism.

[en] A getter for nuclear fuel element plenums is described, consisting of barium or its alloys with aluminum, nickel, zirconium, or titanium, in various combinations, in a particulate form, and disposed in a container preferably of stainless steel screen. (E.C.B.)

[en] Substitution effect in double perovskites, Sr(FeRe)O₃ (SFRO), was studied by Moessbauer spectroscopy and magnetization measurements. The samples were prepared by a sol-gel method. The fraction of alternately ordered Fe1 for SFRO is 72%, and the magnetization measured is consistent with 3x 0.72=2.16μ_B /f.u., but the saturation magnetization drops to about one third of its initial value by substituting 5% Ba for Sr. It was considered to be due to the volume expansion of the lattice and the fine grains formed, as a result of the substitution of Ba ions.

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[en] This paper reports Palladium alloy compositions investigated for suitability as a nonreactive material for the processing of ceramic superconductors. Barium-based superconductors were tested on Pd-Au and Pd-Ag alloys for reactivity. Bismuth-based superconductors were tested on a Pd-Ag alloy. The least reactive was found to be 70% Pd-30% Ag for the barium-based high-temperature superconductors (HTSC), whereas 30% Pd-70% Ag was found to be least reactive for bismuth-based HTSC

[en] To determine peculiarities of α photoinduced variations under subsequent effect of light one studied time dependences of α variations under light effect within typical lengths of waves. One detected dependence of α photoinduced optical absorption at 1.1 μm wave length on the length of acting light wave within 0.6-1.9 μm range. It is shown that in Y₃Fe₅O₁₂ crystal containing Ba impurity α photoinduced increase is associated with formation of Fe⁴⁺ ions in octahedron nodes. Charge is carried due to photoexcitation of transitions of Fe³⁺ octahedron ions. In a crystal containing Si donor impurity α increase results from formation of Fe²⁺ ions at silicon photoionization

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[en] Results of structural, magnetic, and Mössbauer studies of quasi ordered alloys Fe₆₅Al_{35− x}M_x (M_x = Ga, B; x = 0, 5 at %) are presented. The magnetic state of examined structurally–single-phase alloys at low temperatures is interpreted from the viewpoint of magnetic phase separation. An explanation is proposed for the observed behavior of magnetic characteristics of Fe₆₅Al₃₅ and Fe₆₅Al₃₀Ga₅ in the framework of the model of two magnetic phases, a ferromagnetic-type one and a spin density wave. The boron-doped alloy Fe₆₅Al₃₀B₅ is shown to demonstrate behavior that is typical of materials with the ferromagnetic type of ordering.