Increasing the wear and corrosion resistance of steel parts by methods of complex boronikeling and borovolframing

The paper presents ways to increase the wear and corrosion resistance of steel parts by chemical and thermal treatment methods. Comprehensive studies of the structure and properties of St3 steel samples were carried out after simultaneous complex saturation with boron and nickel, boron and tungsten from saturating coatings based on boron carbide. Both compounds of these elements (oxides, carbides, borides) and pure metals were used as suppliers of nickel and tungsten. Studies have shown that multicomponent saturation processes make it possible to form a multiphase structure of a surface layer with a complex of useful properties. Moreover, by chemical-thermal treatment it is possible to obtain such a combination of properties of the hardened product, which cannot be obtained by other methods.

Phase structures and magnetostriction of Fe71.3Ga28.7 alloys prepared by different solidification rates

Magnetostrictive property shows anisotropic characteristics, which are related to phase structure and crystal orientation. In this paper, phase structures and magnetostrictive properties of Fe[Formula: see text]Ga[Formula: see text] at different solidification rates during zone-melting directional solidification were studied. Results show that when the solidification rate exceeds 72 mm/h, the sample has a single A2 structure. A multiphase structure of D03 and A2 is formed when the solidification rate is 36 mm/h. The multiphase structure of L12 and A2 emerges in the sample prepared with a solidification rate of 18 mm/h. The samples with L12 and A2 multiphase structure have excellent low-field magnetostrictive properties, reaching 68 × 10[Formula: see text] under a magnetic field of 20 kA/m.

Increasing of the steels properties by an ecological method of isothermal and step quenching

The relevance. Improving the mechanical properties of steels makes it possible to increase the service life of machine parts, which is an important task in materials science. One of the promising directions in its solution is to obtain in steel a multiphase structure, one of the main components of which is metastable austenite, which undergoes a dynamic deformation martensitic transformation (DDMT) - self-hardening effect under loading (SHL). Methods providing the required structure are isothermal and step quenching. However, at present, when they are carried out for cooling from the austenitizing temperature and holding at the constant temperature used non-environmentally friendly substances: heated oil, molten salts or alkalis. In this regard the actual problem is the exclusion of them from the technological process. The possibility of solving this problem on several steels has shown. Purpose is to show the possibility of increasing the mechanical properties of the studied steels 30ХГСА, 38ХС, 45Г, 40ХН, 10Г12, 60Х18 by using rational modes of an environmentally friendly method of steels quenching (isothermal - for low-alloyed and step - for high-alloyed) due to obtaining in their structure along with other components of metastable residual austenite and the implementation of the SHL effect. Research methods. Samples of the investigated steels after austenitization (in some cases with holding in IСIT) were cooled in water to the temperature of lower bainite formation (isothermal quenching) or stabilization of supercooled austenite to martensitic transformation upon cooling (step quenching), after which they were kept in a furnace and cooled in air to room temperature. Durometric, metallographic and X-ray research methods were used. The tensile properties and impact strength were determined. These properties were compared with those obtained for the studied steels after a typical heat treatment, including quenching in oil and tempering. Results. It is shown that isothermal and step quenching of the investigated steels without the use of non-environmentally friendly substances, carried out according to rational modes, makes it possible to increase the mechanical properties in comparison with their level after the commonly used quenching in oil (fire hazard, the vapors are cancerogenic) and tempering. This is achieved by obtaining a multiphase structure with metastable austenite. Scientific novelty. It is proposed to obtain a multiphase structure with metastable austenite in them to improve the mechanical properties of the studied steels by conducting isothermal and step quenching in an environmentally friendly way without using heated oil, molten salts or alkalis. Practical value. For the studied steels the modes of isothermal and step quenching are determined in an environmentally friendly way, which make it possible to increase the mechanical properties in comparison with the level achieved by quenching and tempering. Wherein in contrast to a similar typical quenching method are excluded the costs of purchasing salts or alkalis, their disposal and washing of products from them. Compared to quenching and tempering, the new method does not require the use of oil and tempering. The latter improves ecology and reduces energy consumption during heat treatment.

The Role of the Multiphase Structure of an Action in Classifying Situations by the Degree of Control (Based on English Utterances)

The article analyses utterances from modern English to establish the peculiarities of the process how the presence or absence of control is manifested in a situation as a multiphase process consisting of seven stages such as a wish, an intention, a decision, planning, preparation, an attempt, a result (success or failure). The implicative character of language representations allows us to assume that a situation can be rendered into utterance explicitly as a complete process or metonymically, through one of the genesis of action stages (using phase and intention markers, lexems with connotative meaning, etc.), and both cases can prove sufficiency to obtain a full and complete image of the situation. Thus, analyzing if a situation represented by an utterance is controlled or non-controlled, we shall focus on the whole process instead of examining one of its parts. The theoretical part of the article explains the choice of the term «control» from semantically similar terms and demonstrates some basic approaches to understanding the concept of control in linguistics. Moreover, the article analyses how the notion of control is applied to predicates and situations; discusses the notions of the genesis of an action and implication that makes it possible to provide a more specific view on what should be considered as a situation. The practical part of the article shares the results obtaining by the analysis of English utterances taken from literature, media or the Oxford Dictionary example bank confirming the sufficiency of a metonymic representation of a situation; it offers a classification of situations based on the completeness of their representation in the language and on the degree of control (depending on what and how many stages are marked as controlled or non-controlled).

A spontaneously healable robust ABA tri-block polyacrylate elastomer with a multiphase structure

Multiphase structural designed acrylate elastomer capable of autonomously repairing structures and restoring functions upon damage was developed via an effective method, realizing good mechanical properties.

Ultraviolet signatures of the multiphase intracluster and circumgalactic media in the romulusc simulation

ABSTRACT Quasar absorption-line studies in the ultraviolet (UV) can uniquely probe the nature of the multiphase cool–warm (104 < T < 106 K) gas in and around galaxy clusters, promising to provide unprecedented insights into (1) interactions between the circumgalactic medium (CGM) associated with infalling galaxies and the hot (T > 106 K) X-ray emitting intracluster medium (ICM), (2) the stripping of metal-rich gas from the CGM, and (3) a multiphase structure of the ICM with a wide range of temperatures and metallicities. In this work, we present results from a high-resolution simulation of an $\sim 10^{14} \, \mathrm{M}_{\odot }$ galaxy cluster to study the physical properties and observable signatures of this cool–warm gas in galaxy clusters. We show that the ICM becomes increasingly multiphased at large radii, with the cool–warm gas becoming dominant in cluster outskirts. The diffuse cool–warm gas also exhibits a wider range of metallicity than the hot X-ray emitting gas. We make predictions for the covering fractions of key absorption-line tracers, both in the ICM and in the CGM of cluster galaxies, typically observed with the Cosmic Origins Spectrograph aboard the Hubble Space Telescope (HST). We further extract synthetic spectra to demonstrate the feasibility of detecting and characterizing the thermal, kinematic, and chemical composition of the cool–warm gas using H i, O vi, and C iv lines, and we predict an enhanced population of broad Ly α absorbers tracing the warm gas. Lastly, we discuss future prospects of probing the multiphase structure of the ICM beyond HST.

High Performance Unalloyed Ductile Cast Iron with Multiphase Structure

An unalloyed ductile cast iron with a multiphase structure is designed by a novel austempering process. The designed austempering treatment consists of initial rapid quenching to 180°C after austenizing at 890°C for 20min, and finally austempering at 220°C for 240min. A multiphase structure comprising lenticular/needle-like prior martensite, fine needle bainitic ferrite and film retained austenite is obtained. The excellent mechanical properties, with a tensile strength of 1530MPa and an elongation of 3.1% can be achieved by controlling the matrix microstructure of 12% prior martensite, 15% retained austenite with 1.64% carbon content, and 73% bainitic ferrite. This is mainly attributed to prior marteniste which can promote refinement of multiphase colonies.

ROHSA: Regularized Optimization for Hyper-Spectral Analysis

Context. Extracting the multiphase structure of the neutral interstellar medium is key to understanding star formation in galaxies. The radiative condensation of the diffuse warm neutral medium producing a thermally unstable lukewarm medium and a dense cold medium is closely related to the initial step leading the atomic-to-molecular (HI-to-H2) transition and the formation of molecular clouds. Up to now, the mapping of these phases out of 21 cm emission hyper-spectral cubes has remained elusive mostly due to the velocity blending of individual cold structures present on a given line of sight. As a result, most of the current knowledge about the HI phases rests on a small number of absorption measurements on lines of sight crossing radio sources. Aims. The goal of this work is to develop a new algorithm to perform separation of diffuse sources in hyper-spectral data. Specifically the algorithm was designed in order to address the velocity blending problem by taking advantage of the spatial coherence of the individual sources. The main scientific driver of this effort was to extract the multiphase structure of the HI from 21 cm line emission only, providing a means to map each phase separately, but the algorithm developed here should be generic enough to extract diffuse structures in any hyper-spectral cube. Methods. We developed a new Gaussian decomposition algorithm named ROHSA based on a multi-resolution process from coarse to fine grid. ROHSA uses a regularized nonlinear least-square criterion to take into account the spatial coherence of the emission and the multiphase nature of the gas simultaneously. In order to obtain a solution with spatially smooth parameters, the optimization is performed on the whole data cube at once. The performances of ROHSA were tested on a synthetic observation computed from numerical simulations of thermally bi-stable turbulence. We apply ROHSA to a 21 cm observation of a region of high Galactic latitude from the GHIGLS survey and present our findings. Results. The evaluation of ROHSA on synthetic 21 cm observations shows that it is able to recover the multiphase nature of the HI. For each phase, the power spectra of the column density and centroid velocity are well recovered. More generally, this test reveals that a Gaussian decomposition of HI emission is able to recover physically meaningful information about the underlying three-dimensional fields (density, velocity, and temperature). The application on a real 21 cm observation of a field of high Galactic latitude produces a picture of the multiphase HI, with isolated, filamentary, and narrow (σ ~ 1−2 km s−1) structures, and broader (σ ~ 4−10 km s−1), diffuse, and space-filling components. The test-case field used here contains significant intermediate-velocity clouds that were well mapped out by the algorithm. As ROHSA is designed to extract spatially coherent components, it performs well at projecting out the noise. Conclusions. In this paper we introduce ROHSA, a new algorithm that performs a separation of diffuse sources in hyper-spectral data on the basis of a Gaussian decomposition. The algorithm makes no assumption about the nature of the sources, except that each one has a similar line width. The tests we made shows that ROHSA is well suited to decomposing complex 21 cm line emission of regions of high Galactic latitude, but its design is general enough that it could be applied to any hyper-spectral data type for which a Gaussian model is relevant.

Influence of Multi-Step Austempering Temperature on Tensile Performance of Unalloyed Ductile Iron

Austempered ductile iron (ADI) has been widely used in various industries due to its excellent combination of high strength, ductility and good wear resistance. The tensile behavior of an unalloyed commercial ADI with a multiphase structure designed by a novel multi-step austempering treatment is investigated. The developed austempering process consists of austenitizing at 890°C for 20min, then initial rapid quenching to 180°C, and isothermal holding at 190, 220, 250°Cfor 120min, and finally air cooling to room temperature. The optimum mechanical properties with an ultimate tensile strength of 1350MPa, a yield strength of 1090MPa, as well as an elongation of 3.5% is achieved at 220°C. This is attributed to a synergistic strengthening effect of multiphase structure including a prior martensite with fine needle bainitic ferrite and film retained austenite.