Dresden 2011 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 31: Postersitzung II
MM 31.11: Poster
Wednesday, March 16, 2011, 17:15–18:45, P5
(contribution withdrawn, duplicate of MM 31.15) SIMS study on the surface elemental distribution in AISI type 304 steel — •Chika Izawa1, Stefan Wagner1, Vladimir Burlaka1, Mauro Martin2, Sebastian Weber2, Anais Bourgeon3, Richard Pargeter3, Thorsten Michler4, and Astrid Pundt1 — 1Institut für Materialphysik der Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen — 2Gemeinsame Forschergruppe, Helmholtz-Zentrum Berlin / Ruhr-Universität Bochum, Universitätsstr. 150 - IA 2/44, D-44801 Bochum — 3TWI Ltd, Granta Park, Great Abington, Cambridge CB21 6AL, United Kingdom — 4Adam Opel GmbH, IPC R2-50, GM Alternative Propulsion Center Europe 65423 Ruesselsheim
Hydrogen embrittlement of low-Ni austenitic stainless steels is suggested to occur due to strain-induced surface alpha -martensite, since the hydrogen diffusivity in bcc phases is expected to be much higher than in the austenitic phase. But, also the local surface chemistry might be responsible for the steel susceptibility. The surface chemistry on two different surface conditions of AISI 304 was investigated by Secondary Ion Mass Spectrometry: a. directly after the machining process and b. after solution annealing process. For both AISI 304 surfaces a layered stacking of Fe- and Cr-oxide was found. The oxide layer thickness was about 5 nm for sample a., and about 10 nm for sample b. The chemical mapping on sample a. shows relatively homogeneous elemental distributions due to the fine microstructure of martensite. For sample b, Fe, Ni, SiO2, FeO and NiO are segregated at the grain boundaries. In contrast, Cr and CrO are distributed in grains.