3D short fatigue crack closure behavior in Ti-6Al-4V alloy investigated using in-situ high resolution synchrotron X-ray tomography

In-situ synchrotron X-ray microtomography has been employed to investigate the three-dimensional (3D) closure behavior of short fatigue crack in Ti-6Al-4V alloy. At a spatial resolution level 1 µm, tomography datasets were taken at two fronts observe time evolution (sometimes called 4D imaging). Owing high level, complex 3D morphology consisting deflections, facet paths and branching/overlap caused by variation microstructural features readily observed together with occurrence closure. This study separated contributions near-tip behind-tip their growth. It was deduced that increase length predominantly affects overall regime. Crack front found be attributable existence different path morphologies which showed varied degree fracture surface roughness due Mode II III displacements. The relationship between closure, tip opening displacement range (?CTOD) growth rate are also discussed.