Nanocrystallization of an amorphous Fe<Subscript>80</Subscript>B<Subscript>20</Subscript> alloy during severe plastic deformation

The structural evolution of an amorphous Fe₈₀B₂₀ alloy subjected to severe plastic deformation at room temperature or at 200°C was studied. Deformation leads to the formation of α-Fe nanocrystals in an amorphous phase. After room-temperature deformation, nanocrystals are localized in shear bands. After deformation at 200°C, the nanocrystal distribution over the alloy is more uniform. Possible causes of the crystallization of the amorphous phase during severe plastic deformation are discussed.     

IR spectra of pyrimidine carboxylic acids and some problems involving their structure

The IR spectra of solid pyrimidinecarboxylic acids and of solutions of them in dioxane and chloroform were obtained. It is demonstrated that the frequencies of the stretching vibrations of the carboxyl C=O groups of acids that are not capable of tautomerism correlate linearly with their acidity constants.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 833–835, June, 1972.     

Comparative study of the spectral and structural properties of EuAl<Subscript>3</Subscript>(BO<Subscript>3</Subscript>)<Subscript>4</Subscript> single crystals with different morphologies

Europium alumoborate EuAl₃(BO₃)₄ microcrystals have been synthesized by the flux method at a temperature of 1050°C. The obtained crystals have different morphologies: both plane-faced and skeletal microcrystals have been observed. Infrared spectroscopy, cathodeluminescence, and transmission electron microscopy investigations of individual microcrystals showed that the spectral and structural characteristics of these morphological forms coincide. The obtained crystals are characterized by the rhombohedral symmetry (sp. gr. R32) with the inclusions of C2/c monoclinic phase domains.     

Structural transformations in the Al<Subscript>85</Subscript>Ni<Subscript>6.1</Subscript>Co<Subscript>2</Subscript>Gd<Subscript>6</Subscript>Si<Subscript>0.9</Subscript> amorphous alloy during multiple rolling

The effect of multiple rolling at room temperature on the structure and crystallization of the Al₈₅Ni_6.1Co₂Gd₆Si_0.9 amorphous alloy has been studied using transmission electron microscopy, differential scanning calorimetry, and X-ray diffraction. The total plastic strain is 33%. It has been shown that the deformation results in the formation of aluminum nanocrystals with the average size that does not exceed 10–15 nm. The nanocrystals are formed in regions of localization of plastic deformation. The deformation decreases the thermal effect of nanocrystallization (∼15%) as compared to the heat release at the first stage of crystallization of the unstrained sample. The morphology, structure, and distribution of precipitates have been investigated. Possible mechanisms of the formation of nanocrystals during the deformation have been discussed.     

Investigation of pyrimidine- 5- and pyrimidine-2-carboxylic acids

The dissociation constants of pyrimidine-5- and pyrimidine-2-carboxylic acids were determined to ascertain the effect of the character of the substituent and its position in the pyrimidine ring. This effect was compared with the effect of substituents on the dissociation constants of the corresponding benzoic acids.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 561–562, April, 1972.     

Reaction of 2-thiouracil with carboxylic acid 1,2,2,2-tetrachloroethylamides

Amidoalkylation of 2-thiouracil with 1,2,2,2-tetrachloroethylamides in the presence of triethylamine or sodium hydroxide gives products of S-, O-, and N-substitution, depending on the reaction conditions.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 95–100, January, 1992.     

Oxygen Vacancies and Valence States of Iron in SrFeO3 – δ Compounds

Physics of the Solid State - The brownmillerite phase has been studied by X-ray diffraction and Mössbauer methods. The available data on single-phase compounds with the perovskite structure in...     

Effect of thermal treatment on the microstructure and magnetic properties of a bulk amorphous Fe72Al5P10Ga2C6B4Si1 alloy

The structure and chemical composition of the phases that form in the controlled crystallization of a bulk amorphous Fe₇₂Al₅P₁₀Ga₂C₆B₄Si₁ alloy are studied by differential scanning calorimetry, transmission electron microscopy, and x-ray diffraction. It was established that, when the alloy is annealed at a temperature above the glass transition point, a nanocrystalline structure consisting of three phases arises. The magnetic properties of amorphous and nanocrystalline samples were studied with a vibrating-sample magnetometer. The coercive force and saturation magnetization of amorphous samples were found to be 1 Oe and 130 emu/g, respectively. The structure and chemical composition of the forming phases and their correlation with the magnetic properties of the samples were determined. __________ Translated from Fizika Tverdogo Tela, Vol. 46, No. 12, 2004, pp. 2158–2163. Original Russian Text Copyright ? 2004 by Abrosimova, Aronin, Kabanov, Matveev, Molokanov, Rybchenko.     

Effect of the Oxygen Content on the Local Environment of Fe Atoms in Anion-Deficient SrFeO3 – δ

Physics of the Solid State - The specific features of the structure in a polycrystalline anion-deficient strontium ferrite SrFeO3&nbsp;–&nbsp;δ have been studied at different...     

Energy Transfer from Ce3+ to Tb3+ in Yttrium and Gadolinium Orthoborates Obtained by Hydrothermal Synthesis

Physics of the Solid State - We studied the structure, IR absorption spectra, the spectral characteristics of photoluminescence and morphology of cerium- and terbium-doped orthoborates of...