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Conversion of MX nitrides to Z-phase in a martensitic 12% Cr steel / Leonardo Cipolla in Acta materialia, Vol. 58 N° 2 (Janvier 2010) 

Public ISBD [article]  in Acta materialia > Vol. 58 N° 2 (Janvier 2010) . - pp. 669-679 Titre : Conversion of MX nitrides to Z-phase in a martensitic 12% Cr steel Type de document : texte imprimé Auteurs : Leonardo Cipolla, Auteur ; Hilmar K. Danielsen, Auteur ; Dario Venditti, Auteur Article en page(s) : pp. 669-679 Note générale : Métallurgie Langues : Anglais (eng) Mots-clés : TEM  XRD  Heat  resistant  steels  Nitrides  Phase  transformation  kinetics Index. décimale : 669 Métallurgie Résumé : A 12% Cr model steel was designed with the purpose of studying the nucleation and growth of modified Z-phase, Cr(V,Nb)N. The model alloy develops Z-phase after relatively short ageing times and contains only nitrides of Cr, V and Nb. Interferences from the presence of carbides and the development of Laves phase were avoided by keeping the C, W and Mo contents as low as possible. Transmission electron microscopy and X-ray diffraction analysis of extracted particles were used to follow the evolutions of phase composition, phase morphology and phase fraction, particularly of the precipitation of Z-phase, during ageing at 600, 650 and 700°C for up to 103 h. The development of Z-phase appears to be accomplished by the diffusion of Cr atoms into (V,Nb)N particles and their subsequent conversion into cubic or tetragonal Z-phase. Studies at various temperatures indicate that Z-phase development proceeds fastest at 650°C and that Z-phase forms faster at prior austenite grain boundaries. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science?_ob=PublicationURL&_tockey=%23TOC%235556%23 [...] [article] Conversion of MX nitrides to Z-phase in a martensitic 12% Cr steel [texte imprimé] / Leonardo Cipolla, Auteur ; Hilmar K. Danielsen, Auteur ; Dario Venditti, Auteur . - pp. 669-679. Métallurgie Langues : Anglais (eng) in Acta materialia > Vol. 58 N° 2 (Janvier 2010) . - pp. 669-679 Mots-clés : TEM  XRD  Heat  resistant  steels  Nitrides  Phase  transformation  kinetics Index. décimale : 669 Métallurgie Résumé : A 12% Cr model steel was designed with the purpose of studying the nucleation and growth of modified Z-phase, Cr(V,Nb)N. The model alloy develops Z-phase after relatively short ageing times and contains only nitrides of Cr, V and Nb. Interferences from the presence of carbides and the development of Laves phase were avoided by keeping the C, W and Mo contents as low as possible. Transmission electron microscopy and X-ray diffraction analysis of extracted particles were used to follow the evolutions of phase composition, phase morphology and phase fraction, particularly of the precipitation of Z-phase, during ageing at 600, 650 and 700°C for up to 103 h. The development of Z-phase appears to be accomplished by the diffusion of Cr atoms into (V,Nb)N particles and their subsequent conversion into cubic or tetragonal Z-phase. Studies at various temperatures indicate that Z-phase development proceeds fastest at 650°C and that Z-phase forms faster at prior austenite grain boundaries. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science?_ob=PublicationURL&_tockey=%23TOC%235556%23 [...]