Journal article
Conversion of MX nitrides to Z-phase in a martensitic 12% Cr steel
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 degrees 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 degrees C and that Z-phase forms faster at prior austenite grain boundaries.
Language: | English |
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Year: | 2010 |
Pages: | 669-679 |
ISSN: | 18732453 and 13596454 |
Types: | Journal article |
DOI: | 10.1016/j.actamat.2009.09.045 |
ORCIDs: | Danielsen, Hilmar Kjartansson , Hald, John and Somers, Marcel A. J. |