Resolution effect on the study of ductile damage using synchrotron X-ray tomography

In this paper, the effect of the resolution on damage characterization in a Dual-Phase steel was investigated. In situ and ex situ tensile tests were carried out on two synchrotron tomographs achieving a voxel size of 1.6 μm and 100 nm. A higher volume fraction of cavity was first qualitatively observed on three-dimensional views and confirmed by quantitative analysis: a large number of cavities not seen at low resolution is detected with a finer voxel size. On the other hand, void growth characterization seems not to be affected: in this studied case, the low resolution is sufficient. The effect of the underestimation of the number of voids is illustrated with the calculation of the mean distance between cavities, this information being a key parameter of void coalescence.