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ISSN Печать: 1093-3611
ISSN Онлайн: 1940-4360
Indexed in
INFLUENCE OF SUBSTRATE COMPOSITION, OXIDE SCALE MORPHOLOGY AND OTHER PHYSICAL PARAMETERS ON THE RESIDUAL STRESSES IN ALUMINA SCALES DEVELOPED AT HIGH TEMPERATURE ON FeCrAl ALLOYS
Краткое описание
Residual stresses in the oxide scale are determined at room temperature by X-ray diffraction using the sin2 Ψ method on various FeCrAl alloys developing an alpha-alumina scale after oxidation tests at 1200°C and 1350°C. Experimental results show that:
- Residual compressive stresses in the alumina scale depend strongly on the morphology of scale: for compact oxide scale developed on a "strong" alloy with oxide dispersions such as MA 956, the stresses are higher than those determined in porous, cellular or buckled scales developed on a "weak" alloy.
- The residual stress level increases with increasing compactness, oxide scale thickness, cooling rate and substrate thickness. Moreover, as the experimental stress level is always lower than the calculated stress level using an elastic model, it is suggested that stress relaxation occurs during cooling and that an elasto-viscoplastic model has to be developed in order to account for the experimental stresses. The first results show an agreement between experimental data and calculations.