High temperature scaling of two phase Fe-50Cu alloy with controlled microstructures

Citation
Ys. Li et al., High temperature scaling of two phase Fe-50Cu alloy with controlled microstructures, MAT SCI E A, 315(1-2), 2001, pp. 245-249
Citations number
25
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science","Material Science & Engineering
Journal title
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
ISSN journal
0921-5093 → ACNP
Volume
315
Issue
1-2
Year of publication
2001
Pages
245 - 249
Database
ISI
SICI code
0921-5093(20010930)315:1-2<245:HTSOTP>2.0.ZU;2-Z
Abstract
In order to study the effect of microstructure changes on the selective oxi dation of the most reactive component in two-phase alloys, the oxidation be haviors of an as-cast Fe-50Cu alloy and its sputtered coating with quite di fferent grain sizes were examined at 800 degreesC. For the as-cast Fe-50Cu alloy, a complex scale formed after air oxidation, containing an outermost layer of copper oxide (CuO + Cu2O) plus an inner region composed of a mixtu re of the oxides of Fe and Cu as well as some Fe-Cu double oxides. A region of internal oxidation of Fe was also observed. Under oxygen pressure low e nough that only Fe can be oxidized, a simultaneous external and internal ox idation of Fe was present. However, a single external Fe oxide scale formed in Fe-50Cu sputtered coating when the grain size was largely reduced. The transition of the oxidation modes above indicates that the grain size reduc tion can promote the selective oxidation of Fe effectively. The mechanism i s mainly attributed to the significantly extended solubility of iron in cop per, and also to the presence of a large number of grain boundaries in the coating, as a direct consequence of the grain size reduction, which may act as short-circuit diffusion paths for the fast outward diffusion of iron du ring oxidation process. (C) 2001 Elsevier Science B.V. All rights reserved.