Experimental characterisation of damage in SiC/SiC minicomposites C. Chateau 1, 2, a , L. G´ el´ ebart 1 , M. Bornert 2, 3 , J. Cr´ epin 4 , D. Caldemaison 2 , E. Boller 5 , C. Sauder 1 , M. Langer 5, 6 , and W. Ludwig 7 1 Commissariat ` a l’Energie Atomique Saclay, DEN/DANS/DMN/SRMA, 91191 Gif/Yvette Cedex, France 2 Laboratoire de M´ ecanique des Solides, Ecole polytechnique, CNRS UMR 7649, 91128 Palaiseau Cedex, France 3 Unit´ e de Recherche Navier, Ecole des Ponts ParisTech, Universit´ e Paris Est, 77455 Marne-la-Vall´ ee Cedex, France 4 Centre des mat´ eriaux, Mines ParisTech, CNRS UMR 7633, BP 87, 91003 Evry Cedex, France 5 European Synchrotron Radiation Facility, 6 rue Jules Horowitz, 38043 Grenoble Cedex, France 6 CREATIS-LRMN, Universit´ e CB Lyon 1, INSA Lyon, CNRS UMR 5220, INSERM U630, 69621 Villeurbanne Cedex, France 7 MATEIS, Universit´ e de Lyon, INSA Lyon, CNRS UMR 5510, 69621 Villeurbanne Cedex, France Abstract. SiC/SiC composites are studied for their potential use in the next generation of nuclear reactors. A multiscale approach is under development to construct a predictive modelling of their complex damageable mechanical behaviour due to their heterogeneous microstructure. This paper focuses on the damage characterisation of the composite at the scale of the tow at room temperature, both in terms of its spatial distribution and its chronology. Such observations are necessary to validate a multiscale damage mod- elling at the microscopic scale. The nonlinear behaviour is related to the accumulation of damages such as matrix cracking, fibre/matrix debonding and finally fibre breaking. Therefore, in-situ tensile tests were carried out on SiC/SiC minicomposites using scan- ning electron microscopy. Specific procedures could be used to get statistical data on the crack evolution. The first results especially show that the growth of the crack openings over the global strain is related to inter-crack distance. This test was complemented by a microtomographic investigation, conducted at the ESRF, performed on a minicomposite submitted to a tensile load. An analysis conducted on the 3D image of a crack shows a slow propagation of the matrix cracking through the minicomposite section. 1 Introduction Because of their favourable mechanical properties at high temperature and after irradiation, SiC/SiC composites are relevant candidates for structural or functional applications in the future nuclear reac- tors. The composite is elaborated from a fibrous preform on the base of woven tows constituted by SiC fibres. The Chemical Vapor Infiltration process (CVI) used to deposit the SiC matrix does not allow to fully densify the composite. The residual porosity is present in the composite between the tows, and in each tows between the fibres. So, this material can be described at two different scales : the scale of the woven composite and the smaller scale of the tow. A multiscale approach is thus under development to build a predictive modelling of their complex and damageable mechanical behaviour a e-mail: camille.chateau@cea.fr © Owned by the authors, published by EDP Sciences, 2010 DOI:10.1051/epjconf/20100620002 EPJ Web of Conferences 6, 20002 (2010) 6 This is an Open Access article distributed under the terms of the Creative Commons Attribution-Noncommercial License 3.0, which permits unrestricted use, distribution, and reproduction in any noncommercial medium, provided the original work is properly cited. Article disponible sur le site http://www.epj-conferences.org ou http://dx.doi.org/10.1051/epjconf/20100620002