This paper shows results of in-situ X-ray diffraction analysis of VHCF cycles in duplex steel samples measured in reflection
geometry at DELTA synchrotron. Due to the grain size a few number of grains inside the illuminated area fulfill the Bragg
condition simultaneously and allow single grain analysis. Rocking curves (RC) recorded after N·107
fatigue cycles (N=0...8) with
increasing stress load reveal changes of shape and intensity of selected austenite and ferrite grains as function of N and are
interpreted by rotation of diffracting lattice plane due to formation of slip bands.
© 2014 The Authors. Published by Elsevier Ltd.
Selection and peer-review under responsibility of the Politecnico di Milano, Dipartimento di Meccanica.
Keywords: austenitic-ferritic duplex steel; VHCF; X-ray diffraction; single grain analysis; peak broadening; peak splitting
1. Introduction
Austenitic-ferritic duplex stainless steel has a high strength and an excellent corrosion resistance. Therefore it is
used, for example, in offshore systems, where the material experiences cyclic loading of high stress amplitudes
which may cause failure after long periodic operation. Laboratory experiment in very high cycle fatigue (VHCF)
regime (up to 109
cycles) may help to evaluate the defect evolution as function of load cycles and to predict possible
origins of crack formation [1]. Besides macroscopic probes TEM and X-ray techniques are important because with
* Corresponding author. Tel.: +49-231-755-5397.
E-mail address: anne.huesecken@tu-dortmund.de
© 2014 Published by Elsevier Ltd. Open access under CC BY-NC-ND license.
Selection and peer-review under responsibility of the Politecnico di Milano, Dipartimento di Meccanica