Berlin 2015 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 17: Postersession I

MM 17.1: Poster

Montag, 16. März 2015, 18:00–20:00, Poster E

Microstructural characterization of hydrogen induced cracking in TRIP-assisted steels by EBSD — •Aurélie Laureys, Tom Depover, Roumen Petrov, and Kim Verbeken — Department of Materials Science and Engineering, Ghent University (UGent), Technologieparkt 903, B-9052 Ghent, Belgium

The present work evaluates hydrogen induced cracking in a TRIP-assisted steel with a complex multiphase microstructure, containing ferrite, bainite and retained austenite. When deformed, the retained austenite transforms to martensite and each structural constituent demonstrates a different behavior in the presence of hydrogen. The goal of this work is to understand the response of the hydrogen saturated multiphase structure to a mechanical load. Tensile tests on notched samples combined with in-situ electrochemical hydrogen charging were performed. The tests were interrupted at a stress just after reaching the tensile strength, since hydrogen induced cracks were found to form after reaching the tensile strength. Such interrupted tests allowed to study hydrogen induced crack initiation and propagation in the material. The microstructure of the samples was characterized by means of scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD). A correlation was found between the occurrence of martensite, which is known to be very susceptible to hydrogen embrittlement, and the initiation of hydrogen induced cracks. The latter were located on the surface in specific high-stressed regions, which were induced due to the presence of the notch.