Interdiffusion structures and paths for multiphase Fe-Ni-Al diffusion couples at 1000 degrees C

    Authors

    Y. H. Sohn; A. Puccio;M. A. Dayananda

    Comments

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    Abbreviated Journal Title

    Metall. Mater. Trans. A-Phys. Metall. Mater. Sci.

    Keywords

    ZERO-FLUX PLANES; TERNARY DIFFUSION; CONSTITUENT REDISTRIBUTION; ZN; COUPLES; ALLOYS; COEFFICIENTS; SYSTEM; INTERFACES; REVERSALS; DEPTHS; Materials Science, Multidisciplinary; Metallurgy & Metallurgical; Engineering

    Abstract

    Diffusion studies were carried out in the Fe-Ni-Al system at 1000 degrees C using solid-solid diffusion couples assembled with beta (beta(2)), gamma (fee) single phase, and (beta + gamma) two-phase alloys. The diffusion couples were encapsulated in quartz tubes under vacuum and annealed for 48 hours. The diffusion structures were examined by optical and scanning electron microscopy. For all beta vs (beta + gamma) couples, growth of the 0 phase was observed as the (beta + gamma) two-phase region recessed with the dissolution of the gamma phase. For multiphase couples assembled with two (beta + gamma) terminal alloys, demixing of the (beta + gamma) two-phase alloys occurred with the formation of single-phase beta and gamma layers. The development of an interphase boundary between the (beta + beta') two-phase region and the gamma phase is reported for the first time for a Fe-Ni-Al diffusion couple assembled with single-phase, 0, and gamma terminal alloys. Various diffusion structures for the couples were related to their diffusion paths constructed from concentration profiles determined by electron probe microanalysis. Interdiffusion fluxes of individual components were determined directly from the experimental concentration profiles and examined in light of diffusional interactions and the development of zero-flux planes and flux reversals. In addition, the boundaries for the miscibility gap between the ordered 8 and disordered beta' phases of the Fe-Ni-Al system at 1000 degrees C were determined with the aid of diffusion couples that developed beta and beta' phases in the diffusion zone.

    Journal Title

    Metallurgical and Materials Transactions a-Physical Metallurgy and Materials Science

    Volume

    36A

    Issue/Number

    9

    Publication Date

    1-1-2005

    Document Type

    Article

    Language

    English

    First Page

    2361

    Last Page

    2370

    WOS Identifier

    WOS:000231396600009

    ISSN

    1073-5623

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