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Core-Shell Structure of Intermediate Precipitates in a Nb-Based Z-Phase Strengthened 12% Cr Steel

Published online by Cambridge University Press:  20 March 2017

Masoud Rashidi ,
Hans-Olof Andrén  and
Fang Liu
Masoud Rashidi*
Affiliation:
Department of Physics, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
Hans-Olof Andrén
Affiliation:
Department of Physics, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
Fang Liu
Affiliation:
Department of Physics, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
*
*Corresponding author. [email protected]
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Abstract

In creep resistant Z-phase strengthened 12% Cr steels, MX (M=Nb, Ta, or V, and X=C and/or N) to Z-phase (CrMN, M=Ta, Nb, or V) transformation plays an important role in achieving a fine distribution of Z-phase precipitates for creep strengthening. Atom probe tomography was employed to investigate the phase transformation in a Nb-based Z-phase strengthened trial steel. Using iso-concentration surfaces with different concentration values, and subtracting the matrix contribution enabled us to reveal the core-shell structure of the transient precipitates between MX and Z-phase. It was shown that Z-phase forms by diffusion of Cr into NbN upon ageing, and Z-phase has a composition corresponding to Cr1+xNb1−xN with x=0.08.

Keywords

Atom probe tomographyphase transformation9–12% Cr steelsZ-phaselocal magnificationprecipitates
Type
Materials Science (Metals)
Information
Microscopy and Microanalysis , Volume 23 , Special Issue 2: Atom Probe Tomography & Microscopy 2016 , April 2017 , pp. 360 - 365
Copyright
© Microscopy Society of America 2017 

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References

Abe, F. (2015). Research and development of heat-resistant materials for advanced USC power plants with steam temperatures of 700°C and above. Engineering 1, 211–224.Google Scholar
Agamennone, R., Blum, W., Gupta, C. & Chakravartty, J.K. (2006). Evolution of microstructure and deformation resistance in creep of tempered martensitic 9-12%Cr-2%W-5%Co steels. Acta Mater 54, 3003–3014.CrossRefGoogle Scholar
Cipolla, L., Danielsen, H.K., Venditti, D., Di Nunzio, P.E., Hald, J. & Somers, M.A.J. (2010). Conversion of MX nitrides to Z-phase in a martensitic 12% Cr steel. Acta Mater 58, 669–679.Google Scholar
Danielsen, H.K. & Hald, J. (2007). A thermodynamic model of the Z-phase Cr(V, Nb)N. CALPHAD 31, 505–514.CrossRefGoogle Scholar
Danielsen, H.K. & Hald, J. (2009). Influence of Z-phase on long-term creep stability of martensitic 9 to 12% Cr steels. VGB PowerTech 5, 68–73.Google Scholar
Danielsen, H.K. & Hald, J. (2009). On the nucleation and dissolution process of Z-phase Cr(V,Nb)N in martensitic 12%Cr steels. Mater Sci Eng A 505, 169–177.CrossRefGoogle Scholar
Danielsen, H.K., Hald, J. & Somers, M. a J. (2012). Atomic resolution imaging of precipitate transformation from cubic TaN to tetragonal CrTaN. Scr Mater 66, 261–264.CrossRefGoogle Scholar
Ettmayer, P. (1971). The crystal structure of the complex nitrides NbCrN and Ta1-x Cr1+x N. Monatsh Chem 102, 858–863.CrossRefGoogle Scholar
Fischmeister, H.F., Karagöz, S. & Andrén, H.-O. (1988). An atom probe study of secondary hardening in high speed steels. Acta Metall 36, 817–825.Google Scholar
Fors, D.H.R. & Wahnström, G. (2011). First-principles investigation of the stability of MN and CrMN precipitates under coherency strains in α-Fe ( M=V, Nb, Ta). J Appl Phys 109, 113709–113709–8.Google Scholar
Gault, B., Moody, M.P., Cairney, J.M. & Ringer, S.P. (2012). Tomographic reconstruction. In Atom Probe Microscopy, Miller, M.K. & Forbes, R.G. (Eds), pp. 185–188. New York, NY: Springer.Google Scholar
Liu, F. & Andrén, H.-O. (2011). Effects of laser pulsing on analysis of steels by atom probe tomography. Ultramicroscopy 111, 633–641.Google Scholar
Liu, F., Rashidi, M., Hald, J., Reißig, L. & Andrén, H.-O. (2016 a). Microstructure of Z-phase strengthened martensitic steels: Meeting the 650°C challenge. Mater Sci Forum 879, 1147–1152.CrossRefGoogle Scholar
Liu, F., Rashidi, M., Johansson, L., Hald, J. & Andrén, H.-O. (2016 b). A new 12% chromium steel strengthened by Z-phase precipitates. Scr Mater 113, 93–96.CrossRefGoogle Scholar
Mayer, K.-H. & Masuyama, F. (2008). The development of creep-resistant steels. In Creep-Resistant Steels, Abe, F., Kern, T.-U. & Viswanathan, R. (Eds.), pp. 15–77. Cambridge, UK: Woodhead Publishing.Google Scholar
Miller, M.K. (2000). Data presentation and analysis. In Atom Probe Tomography Analysis at the Atomic Level, Miller, M.K. (Ed.), pp. 157–193. New York, NY: Kluwer Academic/Plenum Publishers.Google Scholar
Miller, M.K. & Forbes, R.G. (2014). The art of specimen preparation. In Atom-Probe Tomography: The Local Electrode Atom Probe, pp. 189–225. New York, NY: Springer.Google Scholar
Rashidi, M., Liu, F. & Andrén, H.-O. (2014). Microstructure characterization of two Z-phase strengthened 12% chromium steels. In 10th Liège Conference: Materials for Advanced Power Engineering, Lecomte-Beckers, J., Dedry, O., Oakey, J. & Kuhn, B. (Eds.), pp. 71–80. Liège, Belgium: Forschungszentrum Jülich GmbH.Google Scholar
Williams, D.B. & Carter, C.B. (2009). Transmission Electron Microscopy: A Textbook for Materials Science. New York: Springer.Google Scholar