Formation of Diffusion Coatings Based on Nickel and Chromium in the Medium of Fusible Liquid Metal Solutions on Austenitic Steels

2021 ◽  
Vol 316 ◽  
pp. 851-856
Author(s):  
Aleksandr G. Sokolov ◽  
Eduard E. Bobylev ◽  
Ivan D. Storozhenko
Keyword(s):  
Surface Layer ◽  
Liquid Metal ◽  
Saturation Temperature ◽  
Austenitic Steels ◽  
Total Thickness ◽  
Fourth Layer ◽  
Diffusion Coatings ◽  
The Third ◽  
Metal Melts ◽  
Diffusion Metallization

The technology of diffusion saturation of austenitic steels by chromium and nickel in the medium of low-melting liquid metal melts is shown. The saturation temperature was up to 1050°C, and the duration was up to 8 hours. It was found that it is the most effective to apply coatings according to the technological scheme: pre-carburization-diffusion metallization – final carburization. It was found that the coating consists of 4 layers. The surface layer has a thickness of up to 5 mkm and a microtuberance of up to 19500 MPa. The second layer, up to 12 mkm thick, has a microhardness of up to 7500 MPa. The third, up to 50 mkm thick, has a microhardness of 2300 MPa. In the fourth layer, up to 150 mkm thick, the microhardness gradually decreases from 2300 MPa to the microhardness of the base. At the same time, the total thickness of the coatings is up to 200 mkm.

Diffusion Saturation by Titanium from Liquid-Metal Media as Way to Increase Carbide-Tipped Tool Life

2017 ◽  
Vol 265 ◽  
pp. 181-186 ◽  
Author(s):  
A.G. Sokolov ◽  
E.E. Bobylyov
Keyword(s):  
Liquid Metal ◽  
Hard Alloy ◽  
Hard Alloys ◽  
Functional Coatings ◽  
High Quality ◽  
Diffusion Coatings ◽  
Coating Composition ◽  
The Media ◽  
Diffusion Metallization ◽  
Titanium Diffusion

The analysis of the strengths and weaknesses of the existing technologies aimed at improving the performance properties of carbide-tipped tools is presented. The results of studies into the process of diffusion metallization by titanium of a carbide-tipped tool TK type from the media of fusible liquid-metal solutions is given. The influence of titanium diffusion coatings on the durability of carbide tools is investigated. A method of providing formation on hard alloys for wear-resistant titanium high-quality functional coatings is described. The thickness of the coating varies depending on the temperature and exposure time, and ranges from 4 to 6 μm. The hardness of the coatings obtained depends on the temperature of the coating and modes of pre-carburizing, and varies from 24100 to 30000 MPa. The microstructure of the coatings is investigated. The coating consists of two layers: the coating and the transition zone, the size and hardness of which depends on the conditions of pre-carburization and modes of application of the coating. The dependence of the coatings thickness on the duration of the plates exposure in the melt, the temperature of coating composition from the coated hard alloy is investigated.

Crack Path and Liquid Metal Embrittlement Specificity of Austenitic Steels in Mercury at Room Temperature

2021 ◽  
Author(s):  
Thierry Auger ◽  
Bassem Barkia ◽  
Eva Héripré ◽  
Vincent Michel ◽  
Denis Mutel ◽  
...  
Keyword(s):  
Liquid Metal ◽  
Room Temperature ◽  
Crack Path ◽  
Liquid Metal Embrittlement ◽  
Austenitic Steels

scholarly journals Образование нанометровых трещин и фрактолюминесценция при разрушении углеродной керамики

2020 ◽  
Vol 62 (11) ◽  
pp. 1860
Author(s):  
В.И. Веттегрень ◽  
А.Г. Кадомцев ◽  
И.П. Щербаков ◽  
Р.И. Мамалимов ◽  
В.Б. Кулик
Keyword(s):  
Silicon Carbide ◽  
Surface Layer ◽  
Raman Spectrum ◽  
Time Resolution ◽  
Spectrum Analysis ◽  
The Third ◽  
Silicon Crystals ◽  
Slip Planes ◽  
Formation Of Cracks ◽  
Carbon Ceramic

Raman spectrum of the surface layer with a thickness of approximately 80 nm of a porous carbon ceramic was obtained (the porosity was used equal to 5%). Spectrum analysis showed that the ceramics contains crystals of silicon carbide - 6H-SiC and silicon. The destruction of ceramics by diamond microcrystals resulted in fractoluminescence (FL). Spectrum of FL contains two bands at 1.6 and 1.9 eV. The first band is formed by breaking down the silicon crystals, and the second band is formed by breaking down the 6H-SiC crystals. The time dependence of the intensity of FL signals with a time resolution of 2 ns is obtained. Three types of signals were observed: one type of signal is formed when the 6H-SiC crystals break down, the second type of signal is formed when the silicon crystals break down, and the third type of signal is formed when these crystals break down simultaneously. The appearance of signals is associated with the formation of cracks arising from the breaking down of the barriers formed at the intersection of slip planes of dislocations in silicon carbide and silicon crystals. The size of cracks in 6H-SiC is estimated: the smallest ones is 5.5 nm, and the largest is approximately 18 nm.

Study on Heat Transfer and Corrosion Resistance of Anodized Aluminum Alloy in Gallium-Based Liquid Metal

2019 ◽  
Vol 141 (1) ◽  
Author(s):  
Yuntao Cui ◽  
Yujie Ding ◽  
Shuo Xu ◽  
Yushu Wang ◽  
Wei Rao ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Corrosion Resistance ◽  
Aluminum Alloy ◽  
Liquid Metal ◽  
Effective Thermal Conductivity ◽  
Anodic Oxidation ◽  
Convective Heat Transfer Coefficient ◽  
Total Thickness ◽  
Anodized Aluminum

Gallium-based liquid metal (LM) inherits excellent thermophysical properties and pollution-free characteristics. However, it has long been a fatal problem that LM would cause serious corrosion and embrittlement on the classical substrate made of aluminum alloys in constructing chip cooling device. Here, anodic oxidation treatment was introduced on processing the aluminum alloy aiming to tackle the corrosion issues. The prepared anodic oxidation aluminum (AAO) coatings were composed of nanopore layers and barrier layers on a high-purity alumina matrix that were manufactured electrochemically. According to the measurement, the effective thermal conductivity of the anodized aluminum alloy increases with the total thickness of sample increasing. When the total thickness L exceeds 5 × 10−3 m, effects of the porous media on effective thermal conductivity are negligible via model simulation and calculation. It was experimentally found that aluminum alloy after surface anodization treatment presented excellent corrosion resistance and outstanding heat transfer performance even when exposed in eutectic gallium–indium (E-GaIn) LM over 200 °C. The convective heat transfer coefficient of LM for anodized sample reached the peak when the heat load is 33.3 W.

scholarly journals Symbiosis Promotes Fitness Improvements in the Game of Life

2020 ◽  
Vol 26 (3) ◽  
pp. 338-365
Author(s):  
Peter D. Turney
Keyword(s):  
Asexual Reproduction ◽  
Cultural Evolution ◽  
Computational Simulation ◽  
The Other ◽  
Levels Of Selection ◽  
Fourth Layer ◽  
Game Of Life ◽  
The Third ◽  
Evolution By Natural Selection ◽  
Conway’S Game Of Life

We present a computational simulation of evolving entities that includes symbiosis with shifting levels of selection. Evolution by natural selection shifts from the level of the original entities to the level of the new symbiotic entity. In the simulation, the fitness of an entity is measured by a series of one-on-one competitions in the Immigration Game, a two-player variation of Conway's Game of Life. Mutation, reproduction, and symbiosis are implemented as operations that are external to the Immigration Game. Because these operations are external to the game, we can freely manipulate the operations and observe the effects of the manipulations. The simulation is composed of four layers, each layer building on the previous layer. The first layer implements a simple form of asexual reproduction, the second layer introduces a more sophisticated form of asexual reproduction, the third layer adds sexual reproduction, and the fourth layer adds symbiosis. The experiments show that a small amount of symbiosis, added to the other layers, significantly increases the fitness of the population. We suggest that the model may provide new insights into symbiosis in biological and cultural evolution.

THERMODYNAMICS OF THE PROCESSES OF INTERACTION OF LIQUID METAL COMPONENTS IN Fe – Mg – Al – La – O SYSTEM

2018 ◽  
Vol 61 (6) ◽  
pp. 460-465
Author(s):  
G. G. Mikhailov ◽  
L. A. Makrovets ◽  
L. A. Smirnov
Keyword(s):  
Rare Earth ◽  
Liquid Metal ◽  
Rare Earth Elements ◽  
Phase Equilibria ◽  
Thermodynamic Modeling ◽  
Equilibrium Constants ◽  
Rare Earth Metals ◽  
Oxide Systems ◽  
Metal Melts ◽  
Steel Deoxidation

At the present time, rare-earth elements in metallurgy are used in  the form of mischmetal – a rare-earth elements natural mixture (with  atomic numbers from 57 to 71). It contains about 50  wt.  % of cerium.  The remaining elements are mainly lanthanum and niobium. The specific composition is determined by the ore deposit. Inconstant composition of the modifier containing rare-earth metals (REM) can significantly reduce its efficiency. Experimentally, for every branded steels  composition the ratio of various REMs can’t be selected because of the  high costs of obtaining technically pure rare-earth metals. The task of  determining the each rare earth element optimum concentrations and  complex ligature composition can be solved by thermodynamic modeling. In the framework of thermodynamic modeling, the interaction  between magnesium, aluminum and lanthanum with oxygen in liquid  iron is presented. And the thermodynamic model of steel deoxidation  by these active metals composition is considered. On the basis of available literature data on the phase diagrams of the systems MgO – Al2O3 ,  MgO – La2O3 and La2O3 – Al2O3 , the coordinates of the invariant equilibria points in the system MgO – La2O3 – Al2O3 were determined. The  phase diagram of the system MgO – La2O3 – Al2O3 was constructed. It  made possible to establish all phase equilibria realized in the process  of deoxidation of steel with magnesium, lanthanum and aluminum and  to describe these phase equilibria by chemical reactions equations. The  activity of the components in liquid oxide melts was determined using  the theory of subregular ionic solutions, which takes into account the  dependence of the coordination number of cations on the composition  of the oxide melt. The activity of components in metal melts conjugated with oxide systems were determined by Wagner’s theory using the  parameters of the first order interaction. Equilibrium constants values  for the steel deoxidation reactions are installed indirectly by thermodynamic calculations. On the basis of the obtained data the components  solubility surface in the metal melts of Fe – Mg – Al – La – O system  was constructed, which allowed to determine the liquid metal composition regions associated with the corresponding oxide phase.

Corrosion, Corrosion Barrier Development and Mechanical Properties of Steels Foreseen as Structural Materials in Liquid Lead Alloy Cooled Nuclear Systems

2009 ◽  
Author(s):  
Alfons Weisenburger ◽  
Georg Mu¨ller ◽  
Annette Heinzel ◽  
Adrian Jianu ◽  
Heinrich Muscher ◽  
...  
Keyword(s):  
Liquid Metal ◽  
Diffusion Processes ◽  
Creep Behaviour ◽  
Alumina Scale ◽  
Austenitic Steels ◽  
Liquid Lead ◽  
Oxide Scales ◽  
Martensitic Steels ◽  
Pulsed Electron Beam ◽  
Nuclear Systems

A key problem in development of heavy liquid metal cooled nuclear energy and transmutation reactors is the corrosion of structural and fuel cladding materials in contact with the liquid metal. Lead and lead bismuth attack unprotected steel surfaces by dissolution of the metallic components into the liquid metal. It is common understanding that oxide scales on the surface provide the best protection against dissolution attack. However, at temperatures above 500°C austenitic steels suffer from severe dissolution attack, while martensitic steels form thick oxide scales, which hinder heat transfer from the fuel pins and which may break off and eventually lead to a blocking of the coolant channel. Above 500°C steels have to be protected by stable, thin oxide scales. A well understood measure is alloying of stable oxide formers into the surface. Al has shown its ability to form such oxide scales. In the range of 4–10 wt% Al on the surface a stable thin alumina scale is formed by Al diffusion to the surface and selective oxidation. The alumina scale grows only very slowly and prevents migration of oxygen into the steel as well as migration of steel components onto the surface. A number of corrosion experiments showed the good protective behaviour of Al scales in LBE with 10−6 wt% oxygen up to 650°C and for exposure times up to 10000 h. Alloying Al into the surface was done by diffusion processes and also by pulsed electron beam (GESA) melting of a thin surface layer on which Al or an Al containing alloy was precipitated before. This presentation gives an overview on investigations of the steel behaviour in HLM environment carried out to explore their suitability for systems with Pb/LBE coolants. Results of experiments with static and flowing LBE are discussed. The behaviour of steels examined and their respective application ranges are described. Part of the presentation deals with protective barrier development on the steel surface by alloying of Al and its effect on the corrosion resistance. Furthermore the influence of parameters like stresses in the cladding wall, creep behaviour, different flow velocities of the LBE and changing temperatures and oxygen concentrations in LBE is discussed.

scholarly journals Thermodynamic oxidation aspects of metallic impurities and steel surfaces in heavy liquid metal melts

2016 ◽  
Vol 2016 (4) ◽  
pp. 102-113
Author(s):  
Ol’ga Vladimirovna Lavrova ◽  
Aleksandr Yur’evich Legkikh ◽  
Aleksej Nikolaevich Storozhenko
Keyword(s):  
Liquid Metal ◽  
Heavy Liquid ◽  
Metal Melts ◽  
Steel Surfaces ◽  
Metallic Impurities

A novel gravity-assisted automatic docking device for studying diffusion in liquid metal melts assisted by a strong static magnetic field

2021 ◽  
Vol 92 (9) ◽  
pp. 094903
Author(s):  
Ying Liu ◽  
Wenhao Lin ◽  
Bangfei Zhou ◽  
Tianxiang Zheng ◽  
Yunbo Zhong ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Liquid Metal ◽  
Static Magnetic Field ◽  
Metal Melts ◽  
Automatic Docking

Investigations on Cryogenic Turning to Achieve Surface Hardening of Metastable Austenitic Steel AISI 347

2014 ◽  
Vol 1018 ◽  
pp. 153-160 ◽  
Author(s):  
Patrick Mayer ◽  
Benjamin Kirsch ◽  
Jan C. Aurich
Keyword(s):  
Phase Transformation ◽  
Surface Layer ◽  
Surface Hardening ◽  
Cryogenic Cooling ◽  
Austenitic Steels ◽  
Phase Content ◽  
Martensite Formation ◽  
Metastable Austenitic Steel ◽  
Steel Aisi ◽  
Cryogenic Turning

Metastable austenitic steels offer the opportunity of a surface hardening during machining due to a deformation induced martensite formation, substituting downstream hardening-processes. To maintain the necessary low process and workpiece temperatures for a phase transformation from austenite to martensite, cryogenic cooling using CO2-snow was examined in this study. The influence of workpiece diameter, coolant flow rate as well as pre-cooling and pre-surface hardening on the obtainable phase content of martensite in the surface layer was investigated.

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