The effect of Al on the 475 degrees C embrittlement of Fe-Cr alloys
2013 (English)In: Computational materials science, ISSN 0927-0256, Vol. 74, 101-106 p.Article in journal (Refereed) Published
Aluminum addition to ferritic stainless steels was found to effectively suppress the deleterious 475 degrees C embrittlement resulting from the phase decomposition in concentrated Fe-Cr alloys. With the aim of revealing the mechanism behind this prosperous phenomenon, here we investigate the effect of Al on the interfacial energy and formation energy of Fe-Cr solid solutions. The interface between the decomposed Fe-rich alpha and Cr-rich alpha' phases carries a positive excess energy, which is of significant importance on determining the process of phase separation. Using ab initio alloy theory, we show that for the alpha-Fe70Cr20Al10/alpha'-Fe100-x-yCryAlx (0 <= x <= 10, 55 <= y <= 80) interface, the Al content (x) barely changes the interfacial energy. However, for the alpha-Fe100-x-yCryAlx/alpha'-Fe10Cr90 (0 <= x <= 10, 0 <= y <= 25) interface, the interfacial energy increases with Al content due to the variation of the formation energies of the Fe-Cr alloys upon Al alloying. Our ab initio results are supported by CALPHAD calculations, and suggest that the beneficial effect of Al on ferritic steels is mainly due to its thermodynamical effect on the alpha' phase.
Place, publisher, year, edition, pages
Elsevier, 2013. Vol. 74, 101-106 p.
Ab initio, 475 degrees C embrittlement, Stainless steel, Interfacial energy, Phase separation
Engineering and Technology
IdentifiersURN: urn:nbn:se:kth:diva-125754DOI: 10.1016/j.commatsci.2013.03.021ISI: 000321051700014ScopusID: 2-s2.0-84876158103OAI: oai:DiVA.org:kth-125754DiVA: diva2:640489
FunderSwedish Research CouncilEU, European Research Council, 228074
QC 201308132013-08-132013-08-132016-01-19Bibliographically approved