Abstract The use of synchrotron radiation X-ray microtomography rests on the exploitation of the beam coherence, the high spatial (submicron) or temporal resolution (s), in situ and real time experiments and quantitative measurements. Selected original applications showing these capabilities are presented. They include the phase contrast imaging of Si particles in Al alloys, the nucleation of fatigue cracks in structural materials, the visualization of hollow silica spheres within polymer foams, and the real time observation of the semi-solid state in Al–Cu alloys.