Issue 35

T. Auger et alii, Frattura ed Integrità Strutturale, 35 (2016) 250-259; DOI: 10.3221/IGF-ESIS.35.29 250 Focussed on Crack Paths Crack path in liquid metal embrittlement: experiments with steels and modeling T. Auger CentraleSupelec/MSSMAT, UMR CNRS 8579, Grande voie des vignes, Chatenay-Malabry, France S. Hémery ISAE–ENSMA, Institut Pprime, UPR CNRS 3346, département “Physique et mécanique des matériaux”, ENSMA, Téléport 2, 1, avenue Clément-Ader, BP 40109, 86961 Futuroscope Chasseneuil-du-Poitou cedex, France M. Bourcier CentraleSupelec/MSSMAT, UMR CNRS 8579, Grande voie des vignes, Chatenay-Malabry, France C. Berdin University of Paris Sud/ICMMO, CNRS UMR 8182, Orsay, France M. Martin Institute für Materialphysik, Georg-August Universität Göttingen, Germany I. Robertson University of Wisconsin-Madison, Wisconsin, United States of America A BSTRACT . We review the recent experimental clarification of the fracture path in Liquid Metal Embrittlement with austenitic and martensitic steels. Using state of the art characterization tools (Focused Ion Beam and Transmission Electron Microscopy) a clear understanding of crack path is emerging for these systems where a classical fractographic analysis fails to provide useful information. The main finding is that most of the cracking process takes place at grain boundaries, lath or mechanical twin boundaries while cleavage or plastic flow localization is rarely the observed fracture mode. Based on these experimental insights, we sketch an on-going modeling strategy for LME crack initiation and propagation at mesoscopic scale. At the microstructural scale, crystal plasticity constitutive equations are used to model the plastic deformation in metals and alloys. The microstructure used is either extracted from experimental measurements by 3D-EBSD (Electron Back Scattering Diffraction) or simulated starting from a Voronoï approach. The presence of a crack