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Ag diffusion and interface segregation in nanocrystalline γ-FeNi alloy with a two-scale microstructure

Title
Ag diffusion and interface segregation in nanocrystalline γ-FeNi alloy with a two-scale microstructure
Author
이재성
Keywords
Iron–nickel alloys; Nanocrystalline material; Interface diffusion; Interface segregation
Issue Date
2004-02
Publisher
PERGAMON-ELSEVIER SCIENCE LTD
Citation
ACTA MATERIALIA, v. 52, No. 3, Page. 631-645
Abstract
Solute diffusion of Ag in nanocrystalline γ-Fe – 40wt%Ni alloy was studied by means of the radiotracer technique in an extended temperature interval (489–1200 K). The powder metallurgical method was applied to produce nanomaterial which consisted of micrometer-large clusters (agglomerates) of nanometer sized grains. Two types of internal interfaces contributed as short-circuit paths for diffusion: the nanocrystalline grain boundaries (GB) and the inter-agglomerate interfaces (subscript a). Combining the recent results on Ag GB diffusion in coarse-grained γ-Fe – 40wt%Ni alloy and the present diffusion data in the nanocrystalline alloy the Ag segregation was determined as function of temperature. Ag segregates strongly at GBs in the γ-Fe – 40wt%Ni alloy with a segregation enthalpy of Hs=−47 kJ/mol. Knowing the segregation factor, the experimental data on Ag diffusion along both nanocrystalline and inter-agglomerate interfaces in the nanomaterial were systematically analyzed in dependence on the different kinetic regimes. The sensitive radiotracer experiments and the subsequent diffusion profile analysis resulted in a consistent set of diffusion data in the whole investigated temperature range with Arrhenius behavior for both the Ag nano-GB diffusion (D0gb=4.7×10−4 m2/s, Hgb=173 kJ/mol) as well as for the much faster inter-agglomerate interface diffusion (D0a=8.1×10−5 m2/s, Ha=91 kJ/mol).
URI
https://www.sciencedirect.com/science/article/pii/S1359645403006153?via%3Dihub#!https://repository.hanyang.ac.kr/handle/20.500.11754/133302
ISSN
1359-6454
DOI
10.1016/j.actamat.2003.09.045
Appears in Collections:
COLLEGE OF ENGINEERING SCIENCES[E](공학대학) > MATERIALS SCIENCE AND CHEMICAL ENGINEERING(재료화학공학과) > Articles
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