‘Road map’ of the development of the technological component of the strategy of national security

This article is devoted to the development of guidelines for road mapping in planning the development of the technological component of structures of national security. Making the ‘road map’ is reduced to the method of conventional optimization i.e. achievement of the target in conditions of severe limitations of existing resources taking into account the effect of controlled and uncontrolled factors. Such a result can be regarded as a scientific novelty.     

Influence of the configuration of pin on the quality of plastics FSW joints

An investigation on the quality of PVC joints welded by friction stir welding （ FSW ） with different shape of pin was carried out. The results show that when the rotating speed of stir tool is 1 660 r/min and the welding speed is 25 mm/min, the beads welded with upright taper pin are plump and joined well, the average tensile strength of which is 19. 1 MPa （the maximum is 20. 3 MPa）, being 49. 2% of that of parent material. The beads welded with cylindrical pin are also joined rather well plump and smooth, the average tensile strength of which is 17. 6 MPa, being 45.3% of that of parent material. The beads welded with inverted taper and cylindrical screw pin are only partially joined or disjoined. The optimum welding temperature range of PVC is 180 - 190℃. If the temperature beyond 200℃ the material will be burnt. If the temperature is under 170℃ the material will be joined partially or disjoined.     

Influence of the rotation frequency of the magnetic field on the dynamics of the domain structure of thin Fe–3% Si crystals

Some specific features of the reconstruction of the domain structure of thin (0.10 mm) Fe–3% Si single crystals have been investigated depending on the frequency of the magnetization reversal in rotating magnetic fields. The studies have been carried out in the range of frequencies of 60–300 Hz and induction amplitudes of 0.5–1.6 T. It has been established that the magnetization reversal of the samples of this thickness occurs via the displacements of 180° domain walls of the stripe domain structure without the participation of the C-domain walls. A qualitative explanation to the revealed features of the behavior of the domain structure has been given, and their possible contribution to the magnetic losses of the investigated samples has been evaluated.     

Recrystallization and the possibility of the realization of the α-γ diffusionless transformation during the ultrarapid laser heating of steels

Analysis is given of phase and structural transformations occurring upon ultrarapid laser heating in steels with different initial structures, namely, after annealing, after preliminary quenching, quenching and tempering, and after quenching with subsequent deformation and tempering. It is shown that a significant suppression of diffusion processes occurs during laser heating; this circumstance substantially affects the nature of the phase and structural transformations proceeding during laser processing. Special attention is given to studying the process of recrystallization and to the phenomenon of structural heredity during laser heating. The process of recrystallization during laser heating is considered as consisting of two stages, namely, an ordered lattice rearrangement (α-γ transformation) and the recrystallization of austenite that suffered phase-transformation-induced hardening (“phase naklep”). The effect of tempering and plastic deformation on the recrystallization of a preliminarily quenched steel consists in the intensification of the second stage, i.e., of the recrystallization of the transformation-hardened austenite. It is shown that the α-γ transformation during the laser heating of steels with the initial structure of lath martensite occurs by the “mechanism of recovery,” i.e., via the formation and growth of austenite nuclei. In steels with the initial structure of pearlite, the nucleation of austenite during laser heating can occur by a shear martensite-like diffusionless mechanism with the observance of characteristic orientation relationships between the initial ferrite and the newly formed austenite.     

Influence of the Iron Anisothermal Sintering on the Characteristic of the Hollow Cathode Discharge

SINTERING of steels and ceramics is conventionallycarried out in a furnace in a controlled atmosphere.Several alternative techniques have been developedsince 1966, as mentioned by Johnson et al. [1], toobtain components with improved properties, resultingin new applications for powder technology. Plasmasgenerated in microwave cavities, in hollow cathodedevices and microwave or RF-inductively coupleddischarges have all been used for sintering ceramics[2-5]. In the above mentioned papers it …     

Effect of the structure of the oxidized titanium surface on the particle size and properties of the deposited copper–molybdate catalyst

The parameters of wetting of oxide coatings on titanium formed by the method of plasma electrolytic oxidation (PEO) in an aqueous silicate electrolyte with subsequent deposition of a layer of TiO₂ nanoparticles and ultrasonic treatment by a polymer–salt gel including copper and molybdenum compounds have been investigated. The effect of the oxidized surface microrelief, TiO₂ nanoparticle layer, and pore shape and size on impregnation solution spreading and the structure of the copper–molybdenum catalytic coating formed at further thermal treatment has been demonstrated. Complex oxide composites with ultradispersed catalyst particle sizes characterized with high activity in oxidation of carbon black particles have been obtained.     

Research for the method of image acquisition of the molten pool in the TIG welding of aluminum alloy

Obtaining the image of molten pool aluminum alloy‘ s tungsten inert gas (TIG) welding becomes a challenging problem in the welding field. In this paper, a bran-new optical sensor based analyzing the light spectrum was designed, and the clear image of the molten pool during the aluminum alloy‘ s welding using the common industrial CCD camera was obtained. And with the new algorithm provided by myself, the desirable characteristic parameters of the molten pool of aluminum alloy‘ s welding were obtained, and it provides a good base for advanced monitor welding quality.     

Effect of Annealing on the Magnetism of the Sintered NdFeB Magnet

This paper deals with the effect of annealing on the magnetism of the sintered NdFeB magnet with a composition of Nd30B5.1Dy1.2Al0.6Nb0.7Fe62.4. Microstructural investigations of the grain size and grain boundaries with SEM were carried out. Microstructural investigations showed the presence of some Nd-rich phase in grain boundaries and main phase.The results of magnetic properties analysis shows that this non-magnetic Nd-rich phase, produced in annealing process,can increase or decrease the magnetism of the sintered NdFeB-type permanent magnet. Appropriate amount of Nd-rich phase will strengthen the pinning field and elevated the coercive force of magnet, but too many these non-magnetism phases in Nd2Fe14B main phase will decrease it. When the sintered NdFeB magnet was annealed at 3Pa and 492℃ for an hour the coercive force would raise from 915.6kA/m to l164.SkA/m, and the (BH)max from 277.7kJ/m to 349.5kJ/m. However, annealing at a non-optimized temperature at 542℃, microstructure changes in some main phase will leading the decrease of properties.     

Influence of the β-phase morphology on the corrosion of the Mg alloy AZ91

The influence of the microstructure, particularly the morphology of the β-phase, on the corrosion of Mg alloys has been studied using AZ91 as a model Mg alloy. The corrosion behaviour was characterized for five different types of microstructure produced by heat treatment of as-cast AZ91. The influence of microstructure can be understood from the interaction of the following three factors: (i) the surface films can be more or less effective in hindering corrosion and more or less effective in controlling the form of corrosion as uniform corrosion or localised corrosion, (ii) the second phase (the β-phase in AZ91) can cause micro-galvanic acceleration of corrosion and (iii) the second phase can act as a corrosion barrier and hinder corrosion propagation in the matrix, if the second phase is in the form of a continuous network. It is expected that these factors are important for all multi-phase Mg alloys because all known second phases have corrosion potentials more positive than that of the α-phase. A particular example of the corrosion barrier effect is provided by the fine (α + β) lamellar micro-constituent; when a β-phase plate nucleates this micro-constituent, the β-phase plate acts as a corrosion barrier. In contrast, nano-sized β precipitates, produced by aging, caused micro-galvanic corrosion acceleration of the adjacent α-phase. However, it is an important finding that the corrosion rate of the α-phase was decreased by the aging treatments that caused the precipitation of the nano-sized β particles.     

Investigation of the tarnish on the surface of a panda gold coin

In natural environment, tarnish was observed on the surface of historic and contemporary gold coins in several countries. Few years after the emergence of panda gold coins, several red spots were appeared on the surface. To identify the stains and to examine the spots, optical microscope （OM）, scanning electron microscope （SEM）, electron microprobe analysis （EMPA）, X-ray photoelectron spectroscopy （XPS）, and X-ray diffraction （XRD） were used. It was found by microscopic observation that the stain has a dark blue central area surrounded by a large area with a nuance of colors from brown to red. Red spots usually contain holes in the center, which are distributed along the forging stress zones formed in the struck process. From the surface analyses using EMPA, sulfur and silver are detected besides gold, and the contents of Ag and S at the tarnish part are higher than those at the other part. Furthermore, distributions of Ag and S are correlated with the morphology of stains. XPS shows that components of stains are Ag2S and Ag2SO4 and the former is much predominant. These results are confirmed using XRD analysis. Accelerated tarnish test of gold in an atmosphere containing sulfur compound proves that the similar phenomenon appears when a small amount of silver is present on the surface of gold. It can be concluded that the occurrence of tarnish stains is caused by the presence of Ag and S.     

Influence of microwave irradiation on the preparation of novolacs for the shell process

1. IntroductionThe shell process is unique in its ability to makeexcellent reproducible castings with better surface finishand dimensional accuracy than castings made of othersand processes. It is also simpler to operate than many ofother casting processes [1-3]. Therefore, it has been widelyused in the foundry industry and presents a promisingfuture. In recent years the application of shell process inChina has been greatly increased and novolacs consumedin this process are up to tens of thou…     

Effect of alloying on the segregation of embrittling phases in aging of alloys of the Mn−Cu system

Conclusions  

Metallographic Characterization of the Microstructure of Tool Steels

Examination of selectively etched tool steel microstructures by light microscopy provides more information than standard etchants, such as nital, picral or Vilella‘s reagent. Further, the images are more suitable for quantitative measurements, especially by image analysis. Specimens must be properly prepared, damage free, if selective etchants are to be applied successfully. A number of etchants have been claimed to selectively etch certain carbides in tool steels. The response of these etchants has been evaluated using a variety of well-characterized tool steel compositions. While many are selective, they are often selective to more than one type of carbide. Furthermore, their use in image analysis must be evaluated carefully as measurements showed that the amount and size of the carbides are often greater after selective etching as many of these reagents outline and color or attack the carbides. Selective etching of the matrix, leaving the carbides unaffected works well, but no one etchant will cover the broad spectrum of tool steel compositions. No etchant has been found that will color retained austenite in tool steels and image analysis of retained austenite in tool steels are always much lower than by x-ray diffraction unless retained austenite is the dominant phase present in grossly over-austenitized steels.     

An analysis of the dynamic resistance and the instantaneous energy of the CO2 arc welding process

A self-developed welding dynamic arc wavelet analyzer was adopted to analyze and assess the welding process of two CO2 arc welding machines. The experimental results indicate that the instantaneous energy can reflect the influence of the welding current and voltage on dynamic arc characteristic synthetically. Through calculating and analyzing the instantaneous energy, the energy during arc ignition and short circuit in CO2 welding process can be confirmed rationally, thus the foundation for the accurate design and control of the welding current and voltage can be provided. By reducing the ripple disturbance of the dynamic resistance, avoiding peak current and voltage waveform,and enhancing the transition frequency of short circuit suitably, the stability of the welding arc and the weld appearance can be improved.     

Non-isothermal kinetics of the first-stage decomposition reaction of the complex of samarium p-methoxybenzoate with 1,10-phenanthroline

The complex of [Sm(p-MOBA)3phen]2 (p-MOBA, p-methoxybenzoate; phen, 1,10-phenanthroline) was pre- pared and characterized by elemental analysis, IR, and UV spectroscopy. The thermal decomposition of the [Sm(p-MOBA)3phen]2 complex and its kinetics were studied under a static air atmosphere by TG-DTG methods. The in- termediate and residue for each decomposition stage were identified from the TG curve. The kinetic parameters and mecha- nisms of the first decomposition stage were obtained from the analysis of the TG-DTG curves by a new method of process- ing the data of thermal analysis kinetics. The lifetime equation at a mass loss of 10% was deduced as lnτ = – 30.6795 21034.56/T by isothermal thermogravimetric analysis.     

Thermodynamic characteristics of the sorption of adamantane derivatives in glycerol containing the additions of β-cyclodextrin under the conditions of equilibrium gas–liquid chromatography

The thermodynamics of the sorption of adamantane and its derivatives, as well as of some derivatives of n-decane, in glycerol with the addition of β-cyclodextrine (β-CD) is studied under the conditions of gas–liquid chromatography. The constants of an infinitely dilute solution–vapor phase equilibrium (Ostwald coefficient, classical Henry coefficient), as well as equilibrium values of the sorption heat and entropy, are determined. It is shown that accomplishment of the macrocyclic effect associated with the formation of the sorbate–β-CD inclusion complexes significantly affects the thermodynamic characteristics of sorption. The formation of stable complexes between β-CD and adamantane derivatives causes noticeable differences in the sorption of linear and framework molecules. The influence of peculiarities of the molecular structure of adamantane derivatives on the character of their retention in the glycerol–β-CD sorbent is established. Conclusions regarding selective properties of the glycerol–β-CD system with regard to the structural isomers in the series of adamantane derivatives are made. For the first time, the limiting activity coefficients and excess thermodynamic functions of mixing for some adamantane derivatives in the state of infinitely dilute solutions in pure glycerol and glycerol with the additions of β-CD are determined by the chromatographic method.     

Calculation of the Surface Energy of Pure Titanium

Anodic oxidation on pure titanium(α-Ti) surface causes the formation ofinterferential films with different colours,mainly golden,pink and blue.The col-our changes with the thickness of the ox-ide film.One of the factors,which influ-ences the growth rate of the film,may bethe grain surface energy.at least at the     

Study of the Structure of Oxide Interface in the Pt-Rh Alloy by AP-FIM

This paper reports the study of structure of oxide interface in Pt-Rh alloy by atom probe field ion micro-scope (AP-FIM) which is well suited for the study of atom distribution with atomic scale at the surface and in-terface of alloy. AP depth profiles show that oxide interface exist in the Pt-Rh alloy which consists of PtO,RhO, PrO_2 and RhO_2 . The mechanism of oxidation of the alloy is considered as that first oxygen moleculesadsorbed on-to the surface of alloy then dissociate into oxygen atoms (0_2→2O). Consequently oxygen atomsdiffuse into interior through grain boundary forming oxide (M+O→MO). When the concentration of oxygencontinuously increases the dioxide (MO+O→-MO_2) forms.     

Effect of the attenuation of short-wavelength displacements on the formation of transformation twins in α-martensite crystals

In terms of the dynamic theory, one of the possible scenarios of the formation of transformation twins in crystals of α martensite of thin-plate morphology characteristic of Fe–Ni–C alloys with low temperatures of the onset of the γ–α martensitic transformation has been discussed. It has been shown that, in the case of matched velocities of the propagation of relatively short s waves and relatively long l waves, the attenuation of s waves leads to the fragmentation of the twin structure with a monotonic decrease in the fraction of the main component of the twin structure inside fragments.