National Synchrotron Light Source Seminar

The microstructure of heterogeneous materials such as multiphase alloys, composites, cellular materials, etc... has sometimes a very complicated nature. The complexity of this microstructure can nowadays be imaged in 3D using different methods at different scales (FIB/SEM, Atom Probe Tomography, TEM tomography, etc.). The most commonly used of these methods is probably X-Ray Computed Tomography (XRCT) because of its multimaterial, multiscale and non destructive character.

3D imaging (if non destructive like it is the case for XRCT) can also be coupled with in situ loading (1) of the sample (in situ tension or compression, in situ heating, in situ freezing, etc.). The observation of the evolution of the microstructure under load in 3D allows to understand the microscopic mechanisms involved during the transformation/ deformation of these heterogeneous materials as illustrated in Fig. 1 in the case of a dual phase steel.

The 3D image of the initial microstructure of the sample can, in a final analysis stage, be used as a direct input for a numerical simulation of the response of the material to the load, the results of which being directly comparable to the in situ experiments.

This presentation will illustrate this combination of techniques and how we have used it in recent studies in order to understand the deformation of heterogeneous materials.