Kinetics of Diffusion Interaction in Cr15Ni60-AD1 Layered Composite

2020 ◽  
Vol 299 ◽  
pp. 760-765
Author(s):  
Victor Georgievich Shmorgun ◽  
Artem I. Bogdanov ◽  
D.V. Shcherbin
Keyword(s):  
Diffusion Zone ◽  
Heating Temperature ◽  
Layered Composite ◽  
Heterogeneous Structure ◽  
Diffusion Interaction ◽  
Qualitative Effect ◽  
Phase And Chemical Composition ◽  
Kinetics Of ◽  
Temperature Time ◽  
Melted Metal

The structure, phase and chemical composition of the diffusion interaction zone, formed at the interlayer boundary of a layered composite of the alloy Cr15Ni60-aluminum AD1, are studied. The temperature-time conditions for its nucleation and growth are determined. The diffusion zone has a fine predominantly heterogeneous structure and consists of solid solutions based on aluminides Al3Ni, Al3Ni2 and Al7Cr, as well as the ternary compound Al5FeNi. It is shown that the intensity of diffusion zone growth at the interlayer boundary of the bimetal Cr15Ni60-AD1 is determined mainly by the heating temperature, and the dependence of its thickness on the exposure time obeys a parabolic law. The presence of chemical micro-inhomogeneity in the form of a melted metal at the interlayer boundary does not have a qualitative effect on the kinetics of the process: at the first stage, the diffusion zone repeats the contour of the fusion, and then, as the service time increases, «absorbs» it.

scholarly journals INFLUENCE OF ELECTRIC TRANSFER ON DIFFUSION KINETICS IN A BIMETALLIC COMPOSITE OF THE CU - AL SYSTEM

2021 ◽  
pp. 7-11
Author(s):  
O. V. Slautin ◽  
S. P. Pisarev ◽  
D. V. Pronichev ◽  
V. P. Kulevich ◽  
M. N. Chikalov ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Electric Current ◽  
Diffusion Layer ◽  
Diffusion Zone ◽  
Layered Composite ◽  
Diffusion Kinetics ◽  
Bimetallic Composite ◽  
Kinetics Of

The effect of electrotransfer on the kinetics of growth of the diffusion zone during heat treatment of an explosion-welded bimetallic layered composite of the Cu-Al system has been investigated. It is shown that passing an electric current can accelerate the growth of the diffusion layer by up to 30% at short (up to ≈ 60 ÷ 90 minutes) exposures.

Investigation of the Influence of Ultrasound Action on Diffusion Processes in an Explosion-Welded Bimetal System Cu-Al during Heat Treatment

2021 ◽  
Vol 410 ◽  
pp. 306-312
Author(s):  
Oleg V. Slautin ◽  
Dmitriy V. Pronichev ◽  
Evgeniy V. Kuz’min
Keyword(s):  
Heat Treatment ◽  
Composite Material ◽  
Diffusion Zone ◽  
Diffusion Processes ◽  
Intermetallic Phases ◽  
Layered Composite ◽  
Acoustic Vibrations ◽  
Fixed Temperature ◽  
Eutectic Transformation ◽  
Ultrasound Action

The influence of ultrasound on the main regularities of the formation and growth of the diffusion zone at the interlayer boundary of an explosion-welded layered composite material of Al-Cu systems is investigated. It is proved that the effect of ultrasound contributes to the reduction of the latent period of the nucleation of intermetallic phases at the interlayer boundary, lowers the temperature of the beginning of the eutectic transformation (by about 10 ° C), but at the same time does not affect the phase composition of the diffusion zone as a result of homogeneous reactions at the boundary of contact of solids. It has been established that the thickness of the diffusion zone, with the duration of the supplied acoustic vibrations, ensures the absence of cracks in the diffusion zone, leading to delamination of the material, increases by 30-40% at a fixed temperature of intense diffusion.

Effect of Ageing Treatment on the Microstructure and Hardness of the Ti6Al4V Alloy

2015 ◽  
Vol 828-829 ◽  
pp. 194-199 ◽  
Author(s):  
Stephen Masete ◽  
Kalenda Mutombo ◽  
Charles Siyasiya ◽  
Waldo Stumpf
Keyword(s):  
Ageing Time ◽  
Ti6al4v Alloy ◽  
Ageing Temperature ◽  
Heterogeneous Structure ◽  
Martensitic Matrix ◽  
Ageing Treatment ◽  
Solution Treated ◽  
Alloy Hardness ◽  
Temperature Time ◽  
Hardness Values

The effects of ageing temperature, time and cooling medium on the microstructure and hardness of a solution treated Ti6Al4V alloy were investigated. The furnace cooling after ageing for 0.5 hours gave a homogenous structure with higher hardness values than the solution treated and water quenched Ti6Al4V alloy. Increasing the ageing time to 2 hours reduced the alloy hardness. Ageing at temperatures between 500 and 700°C, followed by furnace cooling, led to homogenously distributed α- and β-phases within a fully martensitic matrix leading to improved hardness. A heterogeneous structure with a high variation in microhardness was revealed when ageing at 800 and 900°C.

Acid dissolution of synthetic aluminous goethite before and after transformation to hematite by heating

Clay Minerals ◽  
1995 ◽  
Vol 30 (1) ◽  
pp. 55-65 ◽  
Author(s):  
H. D. Ruan ◽  
R. J. Gilkes
Keyword(s):  
Surface Area ◽  
Heating Temperature ◽  
Dissolution Kinetics ◽  
Frequency Factor ◽  
Dissolution Time ◽  
Unit Surface Area ◽  
Acid Dissolution ◽  
Al Substitution ◽  
Before And After ◽  
Kinetics Of

AbstractMeasurements of the kinetics of acid dissolution of synthetic aluminous goethites and corresponding hematites produced by heating of parent Al-goethites at various temperatures were carried out in 1 M HC1 at 30, 40 and 50°C. Dissolution-time curves show sigmoidal shapes for the goethites (110°C), whereas deceleratory shapes were obtained for most of the partly and fully dehydroxylated samples. The dissolution rate for all materials decreased with increasing Al substitution and increased with increasing dissolution temperature, specific surface area and heating temperature. On a unit surface area basis, hematite dissolved ∼ 2–8 times faster than goethite. Dissolution kinetics of most heated goethite samples (200–260°C) were quite well described (R2 > 0.96) by the modified first-order Kabai equation. The activation energy and frequency factor for dissolution increased with increasing Al substitution.

scholarly journals Studies on the Nature of the Circulating Anticoagulant Directed against Antihemophilic Factor: With Notes on an Assay for Antihemophilic Factor

Blood ◽  
1962 ◽  
Vol 20 (2) ◽  
pp. 137-149 ◽  
Author(s):  
ROBERT T. BRECKENRIDGE ◽  
OSCAR D. RATNOFF
Keyword(s):  
Substrate Concentration ◽  
Clotting Time ◽  
Heat Stable ◽  
Concentration Dependency ◽  
Proportional Relationship ◽  
Kaolin Clotting Time ◽  
Antigen Antibody ◽  
Kinetics Of ◽  
Temperature Time ◽  
Antihemophilic Factor

Abstract Modification of the kaolin clotting time has produced a reliable, simple assay system for antihemophilic factor. This system has been utilized for an investigation of the nature and mode of action of the circulating anticoagulant directed against antihemophilic factor. The anticoagulant has been shown to be present in equal amounts in plasma and serum, to be associated with fractions II and III of plasma prepared by the method of Cohn, to be relatively heat stable and to be stable for prolonged periods at -20 C. Investigation of the kinetics of the anticoagulant-antihemophilic reaction has demonstrated its temperature, time, pH, and substrate concentration dependency. The anticoagulant is not inactivated during the reaction with antihemophilic factor, and there is a proportional relationship between the anticoagulant and the antihemophilic factor during their interaction. No antigen-antibody manifestations could be detected during the anticoagulant-antihemophilic factor reaction. These characteristics support the hypothesis that the inactivation of antihemophilic factor by specific circulating anticoagulants is enzymatic.

Dental Amalgam: Reactor Response

1988 ◽  
Vol 2 (1) ◽  
pp. 87-92 ◽  
Author(s):  
M.I. Marek
Keyword(s):  
Dental Amalgam ◽  
Future Research ◽  
Heterogeneous Structure ◽  
Metallic Elements ◽  
Corrosion Properties ◽  
Critical Issues ◽  
Dependent Strain ◽  
To Receive ◽  
Kinetics Of ◽  
Amalgam Restorations

Dental amalgam continues to be an important restorative material; both fundamental and applied research should be encouraged. The criteria for replacement of amalgam restorations should be re-examined to determine if the integrity of the margins should continue to receive the dominant research interest. In the studies of mechanical properties, first attempts have been made to apply fracture mechanics analysis to dental amalgam. The heterogeneous structure and time-dependent strain of dental amalgam will have to be considered in future studies. More attention should be given to the effects of zinc, which has been shown to improve resistance to marginal fracture. The corrosion properties have been studied in depth, but there are some important unanswered questions. The pathways of corrosion attack in high-copper amalgams and the kinetics of attack in amalgams of different composition should be examined. Biocompatibility of dental amalgam has recently received renewed interest and will have to be examined in more detail. The clinical significance of the release of metallic elements from restorations is generally unknown. Dental amalgam faces strong competition from non-metallic restorative materials. Future research should be more strongly focused on the critical issues. The involvement of scientists from related disciplines should be encouraged, and no effort should be made to restrict the talent pool by a centralization of resources.

New Methods for Studying Glass Corrosion Kinetics

1972 ◽  
Vol 26 (5) ◽  
pp. 530-536 ◽  
Author(s):  
D. M. Sanders ◽  
W. B. Person ◽  
L. L. Hench
Keyword(s):  
Atomic Emission ◽  
New Methods ◽  
Glass Corrosion ◽  
Corrosion Kinetics ◽  
Infrared Reflection ◽  
Corrosive Environments ◽  
Glass Surfaces ◽  
Infrared Reflection Spectroscopy ◽  
Kinetics Of ◽  
Temperature Time

Infrared reflection spectroscopy and atomic emission spectroscopy have been applied to the study of glass corrosion using several new techniques that permit the kinetics of reactions near the surface to be measured on bulk samples as a function of applied stress, flow rate, temperature, time, pH, and relative humidity. Preliminary applications of these methods to the corrosion of a Li2O-2SiO2 glass are discussed. These new methods of studying the corrosion kinetics of glass under well defined conditions promise to aid in a better understanding of the nature of the reactions which take place at glass surfaces when subjected to various corrosive environments.

scholarly journals Impact of microarc carburizing and boriding of steel on diffusion layer structure

2021 ◽  
Vol 63 (11-12) ◽  
pp. 929-934
Author(s):  
Yu. M. Dombrovskii ◽  
M. S. Stepanov
Keyword(s):  
Layer Thickness ◽  
Diffusion Layer ◽  
Current Density ◽  
Steel Surface ◽  
Layer Structure ◽  
Heating Temperature ◽  
High Current Density ◽  
Original Structure ◽  
Heterogeneous Structure ◽  
Coal Particles

Intensification of carburizing and boriding of steel parts is achieved by microarc surface alloying. For carburizing, the parts are immersed in coal powder followed by electric current passing. For boriding, a coating with diffusant is used. Acceleration of diffusion is achieved by action of microarc discharges on the steel surface. The aim of this work was to study the effect of diffusion parameters on thickness, structure, and phase composition of coatings. The samples were made of 20 steel. Surface current density was 0.45 – 0.53 A/cm2. Duration of the process was 2 – 8 min. At the beginning of heating, temperature of the samples increases, and then stabilizes at 930 – 1250 °C due to cessation of micro-formation during combustion of coal particles. After carburizing, a eutectoid mixture is formed on the surface, then, the zone with ferrite-perlite structure is located, which transfers into the original structure. The maximum layer thickness (60 – 390 microns) is reached after 6 – 7 min of heating and then does not increase due to a decrease in the carbon potential during combustion of coal particles. Similar relationship is obtained when boriding: the maximum layer thickness (60 – 340 microns) is reached after 6 – 7 min and then does not increase due to depletion of diffusant source in the coating. At current density of 0.45 A/cm2, the layer consists of a base (a dispersed ferrite-carbide mixture) containing fine inclusions of iron borides and boron carbide. At current densities of 0.49 and 0.53 A/cm2, the layer has heterogeneous structure, with areas of high-hard boride eutectic located at the base. At high current density, diffusion of carbon and boron along the grain boundaries forms Fe – C – B triple eutectic. At lower current density, surface temperature is lower than eutectic formation temperature, so heterogeneous coating structure is not formed. The work results make it possible to choose modes of microarc heating to obtain the required parameters of diffusion layer.

Forging of Copper and Iron Plates by the Damascus Technique

2019 ◽  
Vol 809 ◽  
pp. 253-258
Author(s):  
Susanne Strobl ◽  
Wolfgang Scheiblechner ◽  
Roland Haubner
Keyword(s):  
Composite Material ◽  
Melting Point ◽  
Liquid Metal ◽  
Grain Boundaries ◽  
Diffusion Zone ◽  
Copper Alloys ◽  
Layered Composite ◽  
Damascus Steel ◽  
Small Diffusion ◽  
Steel Grades

Forging of different steel grades is called Damascus technique and results in a layered composite material termed “Damascus steel”, but forging of different copper alloys is termed “mokume gane”. In this paper the joining of copper and iron plates by forging is described. Metallographic investigations showed well bonded interfaces of copper and iron. A very small diffusion zone was observed. To study the diffusion between copper and iron two heat treatments were performed in Ar atmosphere. After 30 minutes at 1000 °C a marginal Cu-Fe interaction took place. Above the melting point of Cu at 1100 °C an intense Cu-Fe interaction was observed, which significantly changes the interface of both metals. Cu penetrated Fe along the grain boundaries and Fe droplets were formed sporadically. This correlates with the typical morphologies of liquid metal embrittlement (LME). Moreover, Fe is dissolved in Cu at 1100 °C and after cooling fine Fe precipitates in the Cu phase were detected.

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