An approach was developed for computer statistical analysis of big, multi-dimensional arrays of technology parameters and industrial product quality indexes.It provides fully objective, mathematically comprehensive, scientifically grounded and physically interpretable description of the manufacturing factor effects on the performance of an industrial product.The approach integrates a basic Data Mining exploratory technique, multiple regression models construction and Monte-Carlo simulations.The approach was applied to industrial statistical arrays investigations for the ASTM A514 steel.The results obtained are in a good accordance with the known Material Science data and were confirmed in industry

The regime parameters providing the improvements of initial cast structure in a white alloy quasi-eutectic pig iron are specified for the applied heat treatment which is based on the early defined principles of microstructure «regeneration» in hetero-phase materials with polymorphic matrixes. Extremely undesirable, typical original microstructure of the iron comprising big, plate-like, «ledeburite» cementite crystals along with coarse-grained colonies of pearlite-like structures was observed. Formation of dispersed, homogeneous in size and spacial distribution sole alloy cementite crystals instead of the «ledeburite» one, within fine grained matrix containing nano-sized cementite particles is shown as a result of the optimal «regenerative» heat treatment employment. Conserving the original iron hardness on the level 60-63 HRC was observed that confirms stability of its phase composition despite the obtained structure`s morphology changes. Unified features of the structure «regeneration» processes in hetero-phase metallic materials of various chemical composition are outlined that provides reliable obtaining high mechanical performance of the materials

Изучено влияние изотермических выдержек при нагреве на морфологию графитовой фазы (ГФ) в промышленных серых и высокопрочных чугунах. Выявлено два варианта такого влияния: 1) частичное растворение пластин ГФ с образованием «разорванных»: тонких пластин, содержащих отдельные крупные сферические частицы ГФ; «сетки» тонких прослоек ГФ на границах зерен феррита; 2) прирост: общей толщины существующих пластин ГФ или размеров исходных сферических частиц ГФ на отдельных локальных участках их поверхностей. Установлено значительное повышение ударной вязкости всех изученных чугунов

Theoretical analysis of the dislocation subgrain boundary (DSB) influence on the microstructure formation at the equilibrium heterogeneous polymorphic phase transformations in polycrystalline alloys has been carried out. Based on the dislocation structure of the DSB and its tendency of reaching equilibrium, evolution of the internal state for the various types of DSB (twisting and tilting) and corresponding elastic strain fields has been considered. Redistribution is shown to develop during the transformation of the crystal elastic energy from the twist to the tilt DSB formed, respectively, by screw and edge dislocations. Localization of the elastic energy on the tilt DSB in the equilibrium crystal state is shown due to the dislocation reactions development between screw dislocations within the corresponding mutually crossing arrays. Taking into account the crystalline lattice elastic distortions around solute atoms and interaction of the atoms with grain boundaries (GB), the analogous chemical element space distributions are shown to appear on DSB and GB. Forming of structure components of specific morphology resulting from the distributions is shown. The possibility to form homogeneous space distributions of atoms as well as dispersed structural constituents under optimal thermal treatment has been stated. Metallographic investigations were conducted using alloy steels of various chemical compositions. Main conclusions of the theoretical analysis have been confirmed by the experimental results

Modern industry uses a lot of elements as additives to improve the service characteristics of metal products that are to be used for various purposes. These elements can be divided into two groups: the first group includes the elements interacting with iron and improving its characteristics (alloying elements), and the second group includes the elements, that modify the characteristics of the structure and properties in an undesirable direction. These are trace elements: S, P, O, As, and others in steel. The negative impact of these elements shows itself as banding, the formation of non-metallic inclusions, flakes, grain boundary segregations et al. The influence of the elements of the both groups on the properties of steel depends on the nature and level of interatomic interaction in the alloy. Computational and analytical study of the major impurity elements in steel impact on the interatomic bond strength and the probability of forming complexes, clusters, and chemical compounds with the basic alloying elements in the steel has been carried out in the work. The theoretical parameter which defines the strength of the ion-covalent bond of two atoms: non-metallic – metallic is the electronegativity of elements. The electronegativity difference of the metal and non-metallic elements increasing, the ionic bonding and thermodynamic stability of these compounds increase. On the other hand, concentration of valent electrons is a universal characteristic of an atomic element which determines many of its properties, and especially the energy of interatomic interaction. Energy calculations of pairwise interatomic impurity elements: H, C, N, S, P, As interaction with Fe and major alloying elements in steel: Mn, Cr, Si, V, Al, Ti, W, Cu, Mo, Nb were made. It has been stated that all the impurity elements except phosphorus, hydrogen and arsenic have sufficient high adhesion with the majority of the metal elements in the modern steels. Phosphorus does not form stable compounds with metals, but has a tendency to form grain boundary segregation (GBS). Niobium, molybdenum and titan change the nature of phosphorus distribution in steel and prevent GBS. Carbon, nitrogen and sulfur are impurity elements having higher energy of ion-covalent interaction with the main metals in steel, therefore tend to form clusters, complexes and chemical compounds.

Accelerator-based analytical facility (AAF) of the Institute of Applied Physics of the National Academy of Sciences of Ukraine is described. The research facility is based on a compact single ended machine with the maximum accelerating potential of 2 MV. The facility has five analytical end-stations: an scanning ion microprobe end-station with spatial resolution of less than 2 μm, a high-resolution Rutherford backscattering spectrometry end-station with a magnetic spectrometer (ΔE/E<1.5×10-3), end-station for elastic recoil detection analysis equipped with an electrostatic spectrometer (ΔE/E<1.5×10-3), end-station for particle induced gamma ray spectroscopy, and an ion induced luminescence end-station. Key specifications of the end-stations and their potential features are given.

An experimental setup for studying the processes occurring during breakdown in the high vacuum are described. The equipment is designed for comparative studies of ply-breakdown processes and the breakdown voltage of the different materials used for accelerator technology. Some first experimental results at this setup are shown in this paper.

Installation for high-dose implantation of metal ions with energies of 20-500 keV was designed. Gas magnetron metal ion source of sputter type was used. Computer simulation of processes of ion beam extraction from plasma boundary of the ion source and beam transporting in the ion-optic system of the implanter was made. Mass-spectra of ion beams were obtained.

The paper studies integral characteristics and one-dimensional distribution of RF power absorption in a helicon plasma with external magnetic field directed at an angle to a plasma plane. Two kinds of working gas heli and hydrogen are considered. A simplified model of a helicon plasma plane layer is used here. Calculation results are used to explain power absorption in a compact helicon ion source with nonuniform external magnet field. An ion source is a part of a nuclear scanning microprobe (NSMP) injector at the Institute of Applied Physics NAS of Ukraine. Calculations for ion source parameters of the NSMP injector show a resonant behaviour of integral RF power absorption as a function of a magnet field inclination angle. A model (planar) geometry is verified here for solution of this problem.

The Schrodinger equation is solved for the wave function of an electron moving in a superposition of external constant and uniform electric and magnetic fields at an arbitrary angle between the field directions. The changing of the potential barrier under influence of the magnetic field parallel to the metal surface is shown.

An analysis of the main existing methods for modelling objects of the automated control is executed in terms of their efficiency: adequacies of control parameters forecasting as well as the necessary amount of calculating operations per a unit time or duration of the calculations. The necessity to use, in general case, the systems of many complicated multicomponent equations of regressive character to achieve adequate determination of evolution of the most real objects has been shown. In order to increase the automated control efficiency a new physically founded method for multilevel modelling the real objects with multidimensional objective functions has been offered. The method consists of: determination of «new» objective function which has close cross-correlation with every initial parameter; development of systems of regressive models relating to a high adequacy a «new» objective function to each control parameter; development of highly adequate regressive model relating a «new» objective function to each entry parameter. Verification of efficiency of the offered method was executed by the modelling the process of the water-air cooling (WAC) for sheets under the conditions of successive WAC and with the use of air-water mixture. A system of the universal physically founded regressive models has been developed for the rolled steels mechanical properties indexes which under the conditions of successive WAC need with the use of the known methods at least 18 iterations to calculate every separate value of the control parameters while according to the offered approach, the proper amount is just 9 iterations and higher forecasting adequacy has been reached

It is considered the transition radiation for the normal incidence of a charged particle on the boundary of plasma medium in the conditions of anomalous skin effect, at the frequencies much less than plasma frequency. The problem is solved in the assumption that electron scattering from the boundary is partially specular and partially diffusive. The spectral density of the radiated energy is obtained for the cases of uniform particle motion and of the motion with two running across the boundary.

It is considered the transition radiation when the charged particle crosses the boundary of plasma medium, in the cases of uniform motion and the motion, which consists of two parts of uniform motion, with two running across the boundary. The solution of the problem is obtained for the conditions when the spatial dispersion is large, skin effect is anomalous, and the reflection of the electrons from the boundary is partially specular and partially diffuse. There are found the differences of characteristics of radiation from ones available in the case of ideally conducting medium and the conditions, for which these differences are considerable. It is considered the question about effectiveness of generation of wide band radiation with use of pulsed accelerators.

The spatial distributions of the RF power absorbed by plasma electrons in an ion source operating in the helicon mode (ω ci < ω < ω ce < ω pe ) are studied numerically by using a simplified model of an RF plasma source in an external uniform magnetic field. The parameters of the source used in numerical simulations are determined by the necessity of the simultaneous excitation of two types of waves, helicons and Trivelpiece-Gould modes, for which the corresponding transparency diagrams are used. The numerical simulations are carried out for two values of the working gas (helium) pressure and two values of the discharge chamber length under the assumption that symmetric modes are excited. The parameters of the source correspond to those of the injector of the nuclear scanning microprobe operating at the Institute of Applied Physics, National Academy of Sciences of Ukraine. It is assumed that the mechanism of RF power absorption is based on the acceleration of plasma electrons in the field of a Trivelpiece-Gould mode, which is interrupted by pair collisions of plasma electrons with neutral atoms and ions of the working gas. The simulation results show that the total absorbed RF power at a fixed plasma density depends in a resonant manner on the magnetic field. The resonance is found to become smoother with increasing working gas pressure. The distributions of the absorbed RF power in the discharge chamber are presented. The achievable density of the extracted current is estimated using the Bohm criterion.

Spatial distribution of RF electromagnetic field absorption by a plasma electron subsystem of ion source is studied. An ion source operates in a helicon mode (w(ci) < w < w(ce) < w(pe)).A simplified model of plasma RF source is used for investigations. Calculations were performed for two particular geometrical dimensions of a discharge chamber with the assumption of two symmetrical modes excitation at two different pressure values of plasma forming gas (helium, hydrogen). The ion source injector parameters of IAP NASU nuclear scanning microprobe were taken for calculations. The calculations show a resonant behaviour of integral RF power absorption as a function of the external magnetic field at a fixed plasma density. Sharpness of resonances becomes smaller as plasma forming gas pressure grows. There is a distribution topography of absorbed power in a discharge chamber for the cases under research. The possible extracted ion current density is evaluated under Bohm criterion.