Investigation of Initial Transient Oxidation of Fe–xCr–6at.%Al Alloys Using Synchrotron Radiation During Heating to 1000 °C in Air

Autor: Isao Saeki, Shigeharu Ukai, Suzue Yoneda, Shigenari Hayashi
Rok vydání: 2016
Předmět:
Zdroj: Oxidation of Metals. 86:357-370
ISSN: 1573-4889
0030-770X
DOI: 10.1007/s11085-016-9641-0
Popis: The initial oxidation behavior of Fe–6Al alloys with different Cr contents (0–24 at.%) during heating to 1000 °C at 50 °C/min, followed by isothermal oxidation for 1 h, was investigated by means of synchrotron radiation in order to clarify the well-known beneficial effect of Cr on external Al2O3 scale formation. An external Al2O3 scale formed on the Cr-containing alloys but did not form on Fe–6Al. A corundum-type transient oxide scale, (Fe,Cr)2O3, formed on all alloys at about 500 °C, and an Al or (Al,Cr)-rich amorphous oxide layer was confirmed to form below the transient scale. This amorphous inner oxide layer was found to provide oxidation resistance up to at least 500 °C for the binary Fe–Al and about 900 °C for the ternary Fe–Cr–Al alloys. Internal precipitates of Al2O3 formed in the alloys when temperatures reached about 900 °C. The volume fraction of these internal precipitates increased with increasing alloy Cr content, which led to be inference that the outward diffusion flux of Al was enhanced by Cr addition.
Databáze: OpenAIRE