[en] In vitro studies have demonstrated that fullerenol, a polyhydroxylated derivative of fullerene (C₆₀(OH)_n n = 12-26), has a high antioxidative potential. Since any radiation injury is mainly a consequence of the action of free radical species, the aim of this study was to examine radioprotective efficiency of fullerenol in whole-body irradiated mice. The experiment was performed on male, adult, white mice, whole-body irradiated with X-rays doses of 6 to 8 Gy (X-ray energy of 8 MV). Fullerenol C₆₀(OH)₂₄ was given in doses of 10 and 100 mg/kg i.p. 30 minutes before irradiation. The experimental groups consisted of 25-30 animals each. The survival rate and body mass gain of irradiated animals were monitored for 30 days after irradiation. The mean lethal times (LT₅₀) of irradiated mice and mean lethal dose of X-rays were calculated and compared. The results showed that fullerenol C₆₀(OH)₂₄, in a dose of 100 mg/kg i.p., prolonged LT₅₀ of irradiated mice. This effect was especially pronounced in mice irradiated with 7 and 8 Gy of X-rays. It seems that radioprotective efficiency of fullerenol C₆₀(OH)₂₄ is more marked in mice irradiated by higher doses of X-rays. (orig.)

[en] The case of near net shape parts made from austenitic steel X2CrNiMo17-13-2 and austenitic-ferritic steels X2CrNiMoN22-5-3 (wrought) and G-X3CrNiMoCuN26-6-3-3 (cast) is interstitially enriched with nitrogen by the diffusion-based process ''solution nitriding''. In order to obtain good corrosion resistance and mechanical properties, the solution nitriding parameters and the applied cooling time are selected so, that precipitates are avoided (X2CrNiMo17-13-2, X2CrNiMoN22-5-3). However, in case of a superimposed hydroabrasive load, the presence of nitrides in the case is found to be beneficial. The solution nitrided and the solution annealed conditions of the steels are compared with respect to their susceptibility to corrosion by means of electrochemical polarisation curves. The erosion corrosion behaviour of the materials is analysed in pilot scale flow-loop tests using particle loaded corrosive and particle loaded non-corrosive media. It is shown that ''solution nitriding'' leads to improved corrosion behaviour and/or improved erosion corrosion resistance, in particular in the case of the duplex steels. (orig.)

[en] There was investigated low cycle fatigue at room temperature of the Fe-18%Cr-16%Ni-3%Mo single crystals in dependence on nitrogen content, crystal orientation, total strain amplitude δε_t=0.6/2.1%. It was shown that macroscopic behavior, picture of slip mode and dislocation structure depend on crystal orientation and nitrogen content. (orig.)

[en] Analysis of existing technologies of high-nitrogen steel production shows that rational nitrogen content in mass production corresponds to moderate high values. Such steels can be smelted under normal or slightly elevated pressure in steelmaking units, using processes of mass- and special metallurgy. High-nitrogen steels with ''overequilibrium'' nitrogen content are promising, but technology and equipment for production of them are complicated, and production of such steels is therefore limited. (orig.)

[en] This work aims to examine the effects of ion energy and current density during nitrogen implantation of steel. The microstructure and the nitrogen distribution at the surface of austenitic and ferritic steels were compared and discussed. The surface of the austenitic X2CrNiMo17-13-2 and ferritic X1CrNiMoNb28-4-2 steel was nitrided by N⁺ ions implantation at doses of 0.3-10 x 10¹⁷ N⁺cm^-2, with an energy of 60 or 100 keV. The beam current density is 1.5 - 3.5 μAvcm^-2. X ray diffraction (XRD), conversion electron Moessbauer spectroscopy (CEMS) were used to investigate the nitride phases resulting from the nitrogen implantation. The formation of Cr₂N, α'-martensite, γ_R-N enriched austenite, Fe₄N γ'-like structure, h.c.p. ε and metastable f.c.c. phases is also detected depending on steel grade and nitriding conditions. Evolution of the phase formation is associated with chromium and nitrogen migration and segregation during the nitriding process. (orig.)

[en] Precipitation in a superaustenitic stainless steel of composition 24Cr-22Ni-7.3Mo-3Mn-0.5N (wt%) has been investigated. Heat treatment at 1050 C for 5 min caused a precipitate structure fairly well resembling that observed in the heat-affected zone after welding. Four different types of precipitates were identified: σ and χ with faceted shapes appeared in some grain boundaries, while Laves and R with more rounded shapes coexisted in other grain boundaries and with more uniform distribution. (orig.)

[en] Strips of a high-nitrogen stainless steel were submitted to rapid heat cycles. The samples were heated by direct electrical conduction up to a peak temperature and immediately water-quenched. The general transformation progress was evaluated by hardness measurements. The morphological features of the α→γ transformation were studied by light and electron microscopy. It was found that austenitization occurs in a relatively short time, although it is temperature sensitive for the given range of heating rates. Two distinct stages of austenitization were related to different thermal stabilities of M₂₃C₆ and Cr₂N precipitates and also to different diffusivities of carbon and nitrogen. (orig.)

[en] The redistribution of interstitial atoms upon tempering of Fe-C-N martensite at 403 K is investigated by means of three dimensional atom probe analysis, X-ray diffraction and dilatometry. Two types of local enrichments form : α^''-like precipitates containing mainly N atoms and ε-like precipitates containing mainly C atoms. (orig.)

[en] The detection of all photons emerging from positron-electron annihilations offers several advantages over the standard Doppler broadening techniques. The effective resolution is improved by √(2); the signal to noise ratio is improved by a factor of over 1000, enabling the identification of specific elements next to the annihilation site. Finally rare decay modes such as annihilation in flight and 3 photon decays can easily be observed. Here an attempt is made to detect iron gettered at defects engineered by ion implantation at specific depths below the surface. The effects of quantum confinement in CdSe nano particles of 1.8 nm to 4.4 nm in diameter is observed and three photon decays in Si are isolated. (orig.)

[en] A reconstruction technique based on Radon transforms is used to obtain 3D electron momentum density ρ(p) using nine recently measured high-resolution Compton profiles (CPs) from a Cu_0.9Al_0.1 disordered alloy single crystal. The method was also applied to nine corresponding theoretical CPs computed within the KKR-CPA first-principles scheme in order to show that our reconstruction procedure reproduces ρ(p) reasonably. We comment briefly on how well a map of the Fermi surface (FS) can be obtained by folding the reconstructed ρ(p) into the first Brillouin zone. (orig.)