Last edited by Tehn
Saturday, October 31, 2020 | History

2 edition of Grain Boundary Diffusion and Grain Boundary Segregation (Diffusion and Defect Data. Defect and Dirrusion Forum,) found in the catalog.

Grain Boundary Diffusion and Grain Boundary Segregation (Diffusion and Defect Data. Defect and Dirrusion Forum,)

  • 250 Want to read
  • 5 Currently reading

Published by Scitec Publications .
Written in English

    Subjects:
  • Condensed matter physics (liquids & solids),
  • Materials science,
  • General,
  • Philosophy

  • Edition Notes

    ContributionsB. Bokstein (Editor), N. Balandina (Editor)
    The Physical Object
    FormatHardcover
    Number of Pages292
    ID Numbers
    Open LibraryOL12344507M
    ISBN 103908450314
    ISBN 109783908450313

    The grain boundary diffusion of 32 P in a polycrystalline Fe wt.% Si alloy was measured with the radiotracer technique under the condition of the Harrison type-B regime (– K) and type-C regime (– K). The triple product P = sδD gb (s denotes the segregation factor, δ the grain boundary width and D gb the grain boundary diffusion coefficient) was obtained in the B regime.   An Ag–Ni semi-empirical potential was developed to simulate the segregation of Ni solutes at Ag grain boundaries (GBs). The potential combines a new Ag potential fitted to correctly reproduce the stable and unstable stacking fault energies in this metal and the existing Ni potential from Mendelev et al ( Phil. Mag. 92 –69). The Ag–Ni cross potential functions were fitted to ab. Solute segregation increases as the grain boundary moves with time. No. of segregates solute atoms also increase with increasing concentration of solute atoms in grain 2 of Al bicrystal. Diffusion-induced grain boundary motion (DIGM) can be caused when solute atoms diffused out of grain boundary (GB) in the presence of solute sink or.   Intergranular fracture due to dynamic embrittlement by impurity segregation at grain boundaries is modelled and simulated in this work. The model is based upon: (i) a bulk diffusion equation including the effect of the hydrostatic pressure, (ii) a grain boundary diffusion equation including the effect of the normal cohesive traction, (iii) a constitutive law for microplasticity accounting .


Share this book
You might also like
Encænia

Encænia

Fast facts for the clinical nursing instructor

Fast facts for the clinical nursing instructor

Villa-Auto Peter Wilson

Villa-Auto Peter Wilson

Bankruptcy hot spots, July 26, 1985, Crowne Plaza Hotel, Downtown Seattle

Bankruptcy hot spots, July 26, 1985, Crowne Plaza Hotel, Downtown Seattle

Adhoc Strategies

Adhoc Strategies

National commercial directory

National commercial directory

His Royal Buckliness

His Royal Buckliness

Naval nuclear propulsion program--1985

Naval nuclear propulsion program--1985

Artists USA 1972-73

Artists USA 1972-73

Colorful gardens

Colorful gardens

Crusoes island

Crusoes island

Man he was

Man he was

voyage of the Vega round Asia and Europe.

voyage of the Vega round Asia and Europe.

Ring round the moon.

Ring round the moon.

Book of common prayer and administration of the sacraments and other rites and ceremonies of the Church ...

Book of common prayer and administration of the sacraments and other rites and ceremonies of the Church ...

Grain Boundary Diffusion and Grain Boundary Segregation (Diffusion and Defect Data. Defect and Dirrusion Forum,) Download PDF EPUB FB2

: Grain Boundary Diffusion and Grain Boundary Segregation (Diffusion and Defect Data. Defect and Dirrusion Forum,) (Defect and Diffusion Forum) (): B.

Bokstein, B. Bokstein, N. Balandina: Books. Grain Boundary Diffusion, Stresses and Segregation: DSS Moscow: Selected, Peer Reviewed Papers From the International Conference on Grain June(Defect and Diffusion Forum) by B. Bokstein (Editor), A. Rodin (Editor), B. Straumal (Editor) & 0 more. Grain Boundary Diffusion and Segregation in the Solid State Phase Transformations - Volume - E.

Rabkin, W. GustAuthor: E. Rabkin, W. Gust. Atomistic study of grain-boundary segregation and grain-boundary diffusion in Al-Mg alloys R.K. Koju, Y. Mishin ∗ Department of Physics and Astronomy, MSN 3F3, George Mason University, Fairfax, VirginiaUSA a r t i c l e i n f o Article Mghistory: (GB) Received 13 August Revised 28 September Accepted 12 October Apparent Diffusion Coefficient Boundary Diffusion Boundary Structure Surface Segregation Boundary Segregation These keywords were added by machine and not by the authors.

This process is experimental and the keywords may be updated as the learning algorithm by: 3. The grain boundary diffusion coefficients, D gb, of the single grain boundary in a true dilute limit of solute concentration are determined in the C kinetic regime and the values of the triple products P = s δ D gb are measured in the B regime (here s and δ are the segregation factor and the diffusional grain boundary width.

The experimental approaches to direct measurement of tracer diffusion along grain boundaries are well-established and, in principle, can give the grain boundary diffusion coefficient and the grain boundary width (or, in the case of an impurity atom, the product of boundary width and the segregation.

Segregation of alloy components to grain boundaries (GBs) and the drastically accelerated atomic mobility in GB regions are two phenomena of significant fundamental interest and technological importance. Surprisingly, the relationships between them remain virtually unexplored.

In this paper, atomistic simulations are applied to understand the effect of GB segregation on GB diffusion. The acceleration of hydrogen diffusion along the grain boundaries is mainly due to high-angle boundaries (random); this can be explained by their disordered structure, which may be likened to an amorphous structure where diffusion of solute becomes easier and faster than in a crystalline structure because of a large excess of free volume.

In Fig. 8(a), the measured triple products, P = sδD gb, of grain boundary diffusion of Ni in quaternary CoCrFeNi and quinary CoCrFeMnNi HEAs by Vaidya et al. () are shown (open symbols). In the expression for the triple product P, s is the segregation factor, δ is the grain boundary width (measured to be about nm in FCC metals and alloys, see Divinski et al., ; Prokoshkina et.

Grain boundary diffusion, stresses and segregation; proceedings. (Defect and diffusion forum; v) by Int'l Conference on Grain Boundary Diffusion, Stresses and Segregation ( Moscow, Russia) Ed.

by B.S. Bokstein et al. Trans Tech Publications, Paperback. New Book. Paperback. This volume collects 34 papers from a June conference discussing current work in grain boundary. The addition of ThO 2 to Y 2 O 3 inhibits grain growth during sintering and allows the sintering process to proceed to theoretical density by maintaining a high diffusion flux of vacancies from the pores to the grain boundaries.

The inhibition of grain growth is accomplished by the segregation of ThO 2 solute at the grain boundaries, causing a decrease in the grain‐boundary mobility. Based on rate equations, the kinetics of atom adsorption, desorption, and diffusion in polycrystalline materials is analyzed in order to understand the influence of grain boundaries and grain size.

The boundary conditions of the proposed model correspond with the real situation in the electrolytes of solid oxide hydrogen fuel cells (SOFC). The role of the ratio of grain boundary and grain. The idea of writing a book on various aspects of grain boundary segregation occurredin summer after my 20 years of experiencein this field.

In fact, some-body else suggested it to me because I am sure I am not capable enough myself to take it up seriously. However, once this idea was conceived, it started to gnaw my mind as a worm in an. Plausible Concepts Necessary and Sufficient for Interpretation of Ceramic Grain‐Boundary Phenomena: II, Solute Segregation, Grain‐Boundary Diffusion, and General Discussion * W.

KINGERY Ceramics Division, Massachusetts Institute of Technology, Cambridge, Massachusetts Ca and Al were found to enhance rates of both interface‐controlled creep and diffusion creep above certain temperatures, and this effect becomes significant with increasing temperature.

We attribute the rate enhancements to grain‐boundary disordering promoted by grain‐boundary segregation of the dopants at near‐solidus conditions. The effect of grain boundary segregation (GBS) on grain boundary diffusion (GBD) is analyzed in frame of the new model.

This model supposes the formation of the specific “nuclei” in a grain. The thickness of the segregation region (with surplus concentration in grain boundary) averages usually from 3 to 6 interatomic distances. As a rule, solute distribution is symmetrical on each side of the fracture surface.

It is shown that maximum of grain boundary. (3) Considering the grain size the present theory predicts the penetration curve in which both the lattice and the grain boundary diffusion play an important role.

(4) The theory also finds the condition that the contribution from the lattice diffusion becomes dominant as compared with that from the grain boundary. Bernardini J, Gas P, Hondros E, Seah M and Nicholson R () The role of solute segregation in grain boundary diffusion, Proceedings of the Royal Society of London.

Mathematical and Physical Sciences,(), Online publication date: 8-Jan Shvindlerman has published over scientific papers and three books, primarily on topics of surface phenomena in solids, diffusion in metals, and phase transitions at grain boundaries in metals.

Grain Boundary Migration in Metals: Thermodynamics, Kinetics, Applications is the result of his research collaboration with Prof. Gottstein. Contrary to the increase in the bulk diffusivity produced by the ‘fast’ diffuser, tin, both grain boundary diffusivities are sharply reduced as the tin content rises.

These and earlier results are interpreted through the effect of tin segregation on the grain boundary energy described by. Because grain boundaries form a continuous network throughout such materials, their properties may limit their practical use. One of the serious phenomena which evoke these limitations is the grain boundary segregation of impurities.

It results in the loss of grain boundary cohesion and consequently, in brittle fracture of the materials. Superplasticity and Grain Boundaries in Ultrafine-Grained Materials, Second Edition, provides cutting-edge modeling solutions surrounding the role of grain boundaries in processes such as grain boundary diffusion, relaxation and grain growth.

In addition, the book's authors explore the formation and evolution of the microstructure, texture and ensembles of grain boundaries in materials. The measured profiles are analyzed by numerical models describing the 6 Li tracer diffusion from the film into the pellet. Experiments in the Harrison type B regime of diffusion kinetics allow for the distinction and simultaneous determination of bulk and grain boundary diffusion coefficients.

The diffusion flux in the vicinity of a grain boundary was found to be greatly modified by the segregation induced by irradiation, leading to the oscillatory behavior of alloy compositions in this region.}, doi = {/t}, journal = {Journal of Nuclear Materials}, number = 2, volume =place = {United States}, year.

Grain boundary and triple junction diffusion in nanocrystalline Cu samples with grain sizes, 〈d〉, of ∼35 and ∼44 nm produced by spark plasma sintering were investigated by the radiotracer method using the 63 Ni isotope. The measured diffusivities, D eff, are comparable with those determined previously for Ni grain boundary diffusion in well-annealed, high purity, coarse grained.

The aim of this chapter is to shed light on the effects of grain boundary segregation on microstructural evolution in nanostructured metallic materials as well as on their mechanical properties. Several key topics will be covered. First, a brief explanation of mechanical stress-driven grain growth in nanostructured Al, Ni, and Cu thin films will be provided in terms of a deformation mechanism map.

The grain boundary diffusion coefficients, D gb, of the single grain boundary in a true dilute limit of solute concentration are determined in the C kinetic regime and the values of the triple products P=sδD gb are measured in the B regime (here s and δ are the segregation factor and the diffusional grain boundary width, respectively).

(). Grain boundary segregation and diffusion of phosphorus in 12Cr–Mo–V steel. Materials Science and Technology: Vol. 8, No. 6, pp. Grain boundary diffusion is more sensitive to grain size when compared to volume diffusion. In contrast to lattice diffusion, the control of elemental diffusion at the grain boundaries can be effective to have a thin and compact oxide scale on the Fe-Cr alloy surface.

This suggests that the grain boundary diffusion is confined at the initial. A grain boundary is the interface between two grains, or crystallites, in a polycrystalline boundaries are 2D defects in the crystal structure, and tend to decrease the electrical and thermal conductivity of the material.

Most grain boundaries are preferred sites for the onset of corrosion and for the precipitation of new phases from the solid. Segregation and Grain Boundary Diffusion in Metals and Elemental Semi-Conductors p Nonlinear Segregation Effects on Grain Boundary Heterodiffusion Extraction of Segregation Term from a Triple Product p Solute Diffusion and Segregation in Grain Boundaries of Silver and Copper.

Grain boundary diffusion and segregation experiments have been carried out in the same metallic solid solutions by means of radio-isotopes and Auger techniques.

It was shown that the mass transport parameters could only be understood by assuming the formation of “2D phases” in “segregated grain boundaries” where the main bonds between. The behavior of adjacent materials at the boundary where they meet is an essential aspect of creating new engineering materials.

Grain Boundary Migration in Metals is an authoritative account of the physics of grain boundary motion, written by two highly respected researchers. They provide a comprehensive overview of current knowledge regarding the migration process and how it affects. In the de-segregation process, the level of phosphorus segregation decreases with increasing holding time t.

But the rate of phosphorus desegregation from grain boundaries to centre is slower compared with that in segregation for the diffusion coefficient of phosphorus atoms, Di, is. The figure below shows Arrhenius plots of self-diffusion in single crystalline and polycrystalline silver.

Derive the activation energies of lattice diffusion and grain boundary diffusion, respectively. When calculating the slope, directly read the number from Y-axis, i.e., read "" as "" instead of 10^ the theory of grain-boundary segregation and blocking of grain-boundary diffusion by reactive elements.

In this paper the current ideas on the transport processes in chromia and the role of rare earth additions on the corrosion behaviour are reviewed.

In addition calculations on crystal lattices and grain boundaries are discussed. Grain boundaries in ultrafine grained (UFG) materials processed by severe plastic deformation (SPD) are often called "non-equilibrium" grain boundaries.

Such boundaries are characterized by excess grain boundary energy, presence of long range elastic stresses and enhanced free volumes. These features and related phenomena (diffusion, segregation, etc.) have been the.

Grain Boundary Diffusion Regimes A B C Illustration of polycrystalline diffusion regimes according to Harrison’s classification scheme (parallel slab model) [Trans Far Soc ]. D is the volume diffusion coefficient, D gb is the grain boundary diffusion coefficient, d is the grain size, δ is the grain boundary width, and t is the diffusion.

The grain-boundary chemistry of magnesium aluminate spinel solid solutions MgO {center dot} nAl{sub 2}O{sub 3} has been investigated in order to understand the mechanism of grain-boundary migration. It is found that although segregation of impurity Ca and Si is common, much larger deviations in grain-boundary stoichiometry are present.The dominant pathway for thin film interdiffusion and interface reactions is often via grain boundaries.

We have made EXAFS measurements of grain boundary constituents for two systems: interdiffusion in Ag-Au bilayers and solid state reaction of Nb with a copper-tin bronze to form Nb3Sn. The Ag-Au results indicate that Au in saturated Ag grain boundaries has an environment similar to a dilute.

The hardening effect caused by the relaxation of nonequilibrium grain boundary structure has been explored in nanocrystalline Ni–W alloys. First, the kinetics of relaxation hardening are studied, showing that higher annealing temperatures result in faster, more pronounced strengthening.