Journal article
Thermally activated growth of lath martensite in Fe–Cr–Ni–Al stainless steel
Department of Mechanical Engineering, Technical University of Denmark1
Materials and Surface Engineering, Department of Mechanical Engineering, Technical University of Denmark2
Department of Micro- and Nanotechnology, Technical University of Denmark3
Magnetic Systems, Department of Micro- and Nanotechnology, Technical University of Denmark4
The austenite to martensite transformation in a semi-austenitic stainless steel containing 17 wt-%Cr, 7 wt-%Ni and 1 wt-%Al was investigated with vibrating sample magnetometry and electron backscatter diffraction. Magnetometry demonstrated that, within experimental accuracy, martensite formation can be suppressed on fast cooling to 77 K as well as on subsequent fast heating to 373 K.
Surprisingly, martensite formation was observed during moderate heating from 77 K, instead. Electron backscatter diffraction demonstrated that the morphology of martensite is lath type. The kinetics of the transformation is interpreted in terms of athermal nucleation of lath martensite followed by thermally activated growth.
It is anticipated that substantial autocatalytic martensite formation occurs during thermally activated growth. The observation of a retardation of the transformation followed by a new acceleration during slow isochronal (i.e. at constant rate) cooling is interpreted in terms of the combined effect of the strain energy introduced in the system during martensite formation, which thermodynamically and/or mechanically stabilises austenite, and autocatalytic nucleation of martensite.
Language: | English |
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Publisher: | Taylor & Francis |
Year: | 2015 |
Pages: | 115-122 |
ISSN: | 17432847 and 02670836 |
Types: | Journal article |
DOI: | 10.1179/1743284714Y.0000000583 |
ORCIDs: | Villa, Matteo , Hansen, Mikkel Fougt , Pantleon, Karen and Somers, Marcel A. J. |