Evolution of the substructure of a novel 12% Cr steel under creep conditions

Journal Article · Sun May 15 00:00:00 EDT 2016 · Materials Characterization

DOI:https://doi.org/10.1016/J.MATCHAR.2016.03.015· OSTI ID:22587146

Kalácska, Szilvia ^[1]; Dománková, Mária ^[2]; Resel, Roland ^[3]; Groma, István ^[1]; Beal, Coline ^[4]; Sonderegger, Bernhard ^[4]; Sommitsch, Christof ^[4]; Poletti, Cecilia ^[4]

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1. Department of Materials Physics, Eötvös Loránd University, Budapest (Hungary)
2. Institute of Materials Science of MTF STU, Trnava (Slovakia)
3. Institute of Solid State Physics, Graz University of Technology, Graz (Austria)
4. Institute of Materials Science and Welding, Graz University of Technology, Graz (Austria)

In this work we study the microstruture evolution of a newly developed 12% Cr martensitic/ferritic steel in as-received condition and after creep at 650 °C under 130 MPa and 80 MPa. The microstructure is described as consisting of mobile dislocations, dipole dislocations, boundary dislocations, precipitates, lath boundaries, block boundaries, packet boundaries and prior austenitic grain boundaries. The material is characterized employing light optical microscopy (LOM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and electron backscatter diffraction (EBSD). TEM is used to characterize the dislocations (mobile + dipole) inside the subgrains and XRD measurements are used to the characterize mobile dislocations. Based on the subgrain boundary misorientations obtained from EBSD measurements, the boundary dislocation density is estimated. The total dislocation density is estimated for the as-received and crept conditions adding the mobile, boundary and dipole dislocation densities. Additionally, the subgrain size is estimated from the EBSD measurements. In this publication we propose the use of three characterization techniques TEM, XRD and EBSD as necessary to characterize all type of dislocations and quantify the total dislocation densty in martensitic/ferritic steels. - Highlights: • Creep properties of a novel 12% Cr steel alloyed with Ta • Experimental characterization of different types of dislocations: mobile, dipole and boundary • Characterization and interpretation of the substructure evolution using unique combination of TEM, XRD and EBSD.

• OSTI ID: 22587146
• Journal Information: Materials Characterization, Vol. 115; Other Information: Copyright (c) 2016 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 1044-5803
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
77 NANOSCIENCE AND NANOTECHNOLOGY
AUSTENITIC STEELS
BACKSCATTERING
DISLOCATIONS
ELECTRON DIFFRACTION
FERRITIC STEELS
GRAIN BOUNDARIES
MARTENSITIC STEELS
OPTICAL MICROSCOPY
PRESSURE RANGE MEGA PA 100-1000
PRESSURE RANGE MEGA PA 10-100
SCANNING ELECTRON MICROSCOPY
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION