Size effects of Y-enriched intermetallic precipitates in Fe-20Cr-5Al-0.25Y alloy on the spallation resistance of thermally grown a-Al_2O_3 scales

摘要

Standard ingot casting and twin-roll strip casting (TRSC) were used to process Fe-20Cr-5Al-0.25Y (wt.%) alloy, in which Y-enriched intermetallic precipitates with different sizes had been formed. Cyclic oxidation tests were carried out at 1200 degrees C in air, and the size effects of precipitates in alloy on the spallation resistance of thermally grown alpha-Al2O3 scales were investigated. The results clearly demonstrated that the spallation resistance of alpha Al2O3 scales could be improved by refining the Y-enriched precipitates, which was attributed to the fact that the small precipitates can generate high density of interfacial oxides to effectively key the alumina scale to the substrate.