ISSN:
1662-9752
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
A family of creep-resistant, Al2O3-forming austenitic (AFA) stainless steels was recentlydeveloped. The alloys exhibit excellent oxidation resistance up to ∼800°C, but are susceptible tointernal attack of Al at higher temperatures. In the present work, higher levels of Ni, Cr, Al, and Nbadditions were found to correlate with improved oxidation behavior at 900°C in air. The alloysgenerally appeared to be initially capable of external Al2O3 scale formation, with a subsequenttransition to internal attack of Al (internal oxidation and internal nitridation) that is dependent onalloy composition. Compositional profiles at the alloy/scale interface suggest that the transition tointernal oxidation is preceded by subsurface depletion of Al in the lower-Al compositions. In higherAl-containing compositions, NiAl second-phase precipitates act as an Al reservoir, and Al depletionmay not be a key factor. Alloy design directions to increase the upper-temperature limit ofprotective Al2O3 scale formation in these alloys are discussed
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/19/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.595-598.725.pdf
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