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M: Metallphysik

M 32: Poster TU B (Symposium Tomographic Methods in Materials Research M-32.32-55)

M 32.51: Poster

Monday, March 7, 2005, 14:30–16:30, Poster TU B

3D-analysis of the crystal orientation relationship and growth process of lenticular martensite in Fe-30mass%Ni alloy — •Hisashi Sato and Stefan Zaefferer — Department of Microstructure Physics and Metal Forming, Max-Planck-Institute for Iron Research, Max-Planck-Strasse, 1, Dusseldorf, Germany

The 3-dimensional structure of lenticular martensite in Fe-Ni alloys has been studied by EBSD orientation microscopy on serial sections produced in a focused ion beam - scanning electron microscope (FIB-SEM). With a spatial resolution of 50 x 50 x 50 nm and an orientation resolution of 0.5^∘ very fine details of the microstructure can be observed and a formation mechanism is proposed.

In previous studies [1-2], it has been reported that the crystal orientation relationship (OR) between martensite and austenite in Fe-Ni alloy is Nishiyama-Wassermann. However, this OR is an average one which can only partly be confirmed by our local measurements. The 3-dimensional measurements show that martensite nucleates with a Kurdjumov-Sachs relationship which then rotates towards NW with further growth.

[References]

1. W.P.Liu and H.J.Bunge: Mater. Lett.,10(1991)343.

2. G.Bruckner, A.Kontges and G.Gottstein: Steel Res.,70(1999)188.