Damage assessment in metallic structural materials using high resolution synchrotron X-ray tomography

High resolution synchrotron X-ray tomography has been used to image damage development during mechanical loading in model metallic materials. First, the initiation, growth and coalescence of porosities in the bulk of two metal matrix composites have been imaged at different stages of a tensile test (2 mum resolution). Quantitative data on damage development has been obtained and related to the nature of the composite matrix. Second, 3D images of one fatigue crack have been obtained post mortem for a cast Al alloy. Thanks to a special decoration technique, the shapes of the crystallographic grains surrounding the crack have also been imaged (0.7 mum resolution). Local deviations of the crack have been related to the presence of grain boundaries. (C) 2002 Elsevier Science B.V. All rights reserved.