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Al2O3 Scale Development on Iron Aluminides

Journal Article · · Journal of Materials Research
OSTI ID:900779
The structure and phase of the Al{sub 2}O{sub 3} scale that forms on an Fe{sub 3}Al-based alloy (Fe-28Al-5Cr) (at %) was investigated by transmission electron microscopy (TEM) and photoluminescence spectroscopy (PL). Oxidation was performed at 900 C and 1000 C for up to 190 min. TEM revealed that single-layer scales were formed after short oxidation times. Electron diffraction was used to show that the scales are composed of nanoscale crystallites of the {theta}, {gamma}, and {alpha} phases of alumina. Band-like structure was observed extending along three 120{sup o}-separated directions within the surface plane. Textured {theta} and {gamma} grains were the main components of the bands, while mixed {alpha} and transient phases were found between the bands. Extended oxidation produced a double-layered scale structure, with a continuous {alpha} layer at the scale/alloy interface, and a {gamma}/{theta} layer at the gas surface. The mechanism for the formation of Al{sub 2}O{sub 3} scales on iron aluminide alloys is discussed and compared to that for nickel aluminide alloys.
Research Organization:
Ernest Orlando Lawrence Berkeley NationalLaboratory, Berkeley, CA (US)
Sponsoring Organization:
USDOE Director. Office of Science. Office of AdvancedScientific Computing Research. Office of Basic EnergySciences
DOE Contract Number:
AC02-05CH11231
OSTI ID:
900779
Report Number(s):
LBNL--59099; BnR: KC0201020
Journal Information:
Journal of Materials Research, Journal Name: Journal of Materials Research Journal Issue: 6 Vol. 21; ISSN JMREEE; ISSN 0884-2914
Country of Publication:
United States
Language:
English