3-D growth of a short fatigue crack within a polycrystalline microstructure studied using combined diffraction and phase-contrast X-ray tomography

摘要

X-ray diffraction contrast tomography is a recently developed, non-destructive synchrotron imaging technique which characterize microstructure and grain orientation in polycrystalline materials in three dimensions. By combining it with propagation-based phass contrast tomography it is possible to get a full picture description for the analysis of local crack growth rate of short fatigue crack in three dimensions: the three-dimensional crack morphology at different propagation stages, and the shape and orientation of the grair around the crack. An approach has been developed on the metastable beta titanium alloy Ti 21S that allows for visualization and ana ysis of the growth rate and crystallographic orientation of the fracture surface.