Trip steel specimen preparation for advanced sem and EBSD

0536988 - ÚPT 2021 RIV CZ eng C - Conference Paper (international conference)
Ambrož, Ondřej - Mikmeková, Šárka - Hegrová, J. - Aoyama, T.
Trip steel specimen preparation for advanced sem and EBSD.
METAL 2020. 29th International Conference on Metallurgy and Materials. Proceedings. Ostrava: TANGER, 2020, s. 518-522. ISBN 978-80-87294-97-0. ISSN 2694-9296.
[METAL 2020. International Conference on Metallurgy and Materials /29./. Brno (CZ), 20.05.2020-22.05.2020]
R&D Projects: GA TA ČR(CZ) TN01000008
Institutional support: RVO:68081731
Keywords : TRIP steel * metallography * SEM * EBSD * AFM
OECD category: Materials engineering

Modern scanning electron microscopy (SEM) allows observations of specimens with high surface sensitivity. The surface sensitivity is significantly affected by the accelerating voltages. With the development of the scanning electron microscopy, the requirements for the surface quality of samples increase. Metallographic methods originally intended for light microscopy become insufficient. The problem occurs especially with multiphase materials having a fine-grained structure. The investigated TRIP steel consists of a ferritic-bainitic matrix, retained austenite and martensite phases. The sizes of the smallest phases are nanometer units. The volume of residual austenite was determined by X-ray diffraction. The basic preparation of all tested samples involved conventional metallographic grinding and very fine mechanical polishing. One sample was analysed in this state. Other samples were subsequently chemically polished, electropolished and chemical-mechanically polished. The specimens were observed in the SEM using a SE and a BSE detector at low energies immediately after the preparation. An EBSD was performed in the same areas to characterize the retained austenite. Topographical imaging by special AFM, integrated into the SEM, demonstrated that the mechanical polishing results in surface deformation and residual austenite is transformed. All other methods have their specifics and for modern sensitive SEM instruments it is necessary to optimize individual procedures.
Permanent Link: http://hdl.handle.net/11104/0314747