Statistical self-similarity in Rhines’ concept of unique multiphase diffusion paths on the ternary gibbs’ isotherm

There exist several interesting phenomena and observations reported in literature for isothermal diffusion in multicomponent systems. Such phenomena include uphill diffusion, development of zero-flux planes and flux reversals for individual components, flux reversals at interfaces, and instability at interfaces and multiphase layer development. In addition, uncommon diffusion structures exhibiting unusual diffusion paths can develop in both single phase and multiphase diffusion assemblies. An overview of such phenomena is presented to highlight the role of interactions among diffusing components with the aid of selected diffusion studies carried out in multicomponent alloy systems, aluminides, silicides, and nuclear fuels.

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Horns on diffusion paths in multiphase diffusion couples

Acta Materialia ◽

10.1016/j.actamat.2006.07.019 ◽

2006 ◽

Vol 54 (20) ◽

pp. 5501-5507 ◽

Cited By ~ 15

Author(s):

K. Wu ◽

J.E. Morral ◽

Y. Wang

Keyword(s):

Diffusion Couples ◽

Diffusion Paths ◽

Multiphase Diffusion

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Multiphase Diffusion in Fe−Ni−Al System at 1000°C: I. Diffusion structures and diffusion paths

Metallurgical Transactions A ◽

10.1007/bf02812004 ◽

1979 ◽

Vol 10 (10) ◽

pp. 1407-1414 ◽

Cited By ~ 17

Author(s):

G. H. Cheng ◽

M. A. Dayananda

Keyword(s):

Diffusion Paths ◽

Multiphase Diffusion ◽

And Diffusion

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Structural Imperfections in thin Oxide Films Formed on Some Fe- and Ni-Base Alloys

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100069545 ◽

1970 ◽

Vol 28 ◽

pp. 510-511

Author(s):

L. P. Lemaire ◽

D. E. Fornwalt ◽

F. S. Pettit ◽

B. H. Kear

Keyword(s):

Oxide Scale ◽

Oxidation Process ◽

Short Circuit ◽

Protective Oxide ◽

Protective Oxide Scale ◽

Thin Oxide Films ◽

Diffusion Paths ◽

Oxidation Resistant ◽

Structural Imperfections ◽

Short Circuit Diffusion

Oxidation resistant alloys depend on the formation of a continuous layer of protective oxide scale during the oxidation process. The initial stages of oxidation of multi-component alloys can be quite complex, since numerous metal oxides can be formed. For oxidation resistance, the composition is adjusted so that selective oxidation occurs of that element whose oxide affords the most protection. Ideally, the protective oxide scale should be i) structurally perfect, so as to avoid short-circuit diffusion paths, and ii) strongly adherent to the alloy substrate, which minimizes spalling in response to thermal cycling. Small concentrations (∼ 0.1%) of certain reactive elements, such as yttrium, markedly improve the adherence of oxide scales in many alloy systems.

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