H. Proudhon à la Gordon Research Conférence

The drive for innovation pushes forward better performance of materials in severe service environments.  For structural materials, understanding the deep nature of plastic deformation and fatigue fracture as a function of the material microstructure is extremely important.  Third generation synchrotrons (and free electron lasers in the future) are developing throughout the world to provide scientists with stable, high brilliant X-ray sources to investigate material problems. As such, the increasing popularity and capabilities of X-ray tomography to image the bulk of materials in three dimensions brings forward a new way to validate large-scale material simulations. For structural materials, the non-destructive nature of these tools enables mechanical stress rigs for in situ measurements. Recent experimental developements will be presented through several applications, including fatigue cracking in aerospace alloys and early plastic deformation of polycrystalline materials. Progress and limits in terms of spatial and temporal resolution will be discussed. Characterisation at the micron scale by in situ imaging using either absorption, phase or diffraction contrasts, can often serve as direct input for full field simulations. One of the key challenges is therefore to link 3D microstructure characterization tools with computational models to predict engineering properties such as strength or fatigue resistance. This can be accomplished using direct measurement of 3D microstructures or synthetically generated images using sophisticated models to ensure representativity. Examples of image based large-scale computation using the crystal plasticity finite element method will be presented. Automated image processing, meshing strategy and the need for high performance computing will also be discussed.