Fig. 1.

Morphological-compositional characterization of the fracture surfaces of the samples performed by means of field emission scanning electron microscopy (FESEM, SUPRATM 40, Zeiss) equipped with energy dispersive X-ray spectroscopy (EDS), at the Department of Applied Sciences and Technology (Politecnico di Torino, Italy). FESEM image from the bigger of the two fragments (magnification 235×). The clamping surfaces are evident. They developed due to the sliding of the material planes and appear as stratified beaches, witnessing the progress of the crack. There is no laminating trace (the dark lines are in fact caused by chrome plating).