Determination of stretch zone width and height by powerful 3D SEM imaging technology

The focus of the present study is to demonstrate a new method to determine the stretch zone height and width using a fast and easy 3D imaging tool in the scanning electron microscope. The SEM MIRA3 XMU from TESCAN Company is equipped with a unique real-time 3D imaging technology. The paper compares 2D with 3D imaging (as anaglyph pictures) of several fracture surfaces after static fracture toughness tests on austenitic and ferritic steels as well as on cast iron showing more or less well pronounced stretch zones. The 3D images give a clear view of the fracture topography, which can hardly be achieved in 2D by tilting and looking from side positions. It is shown, how 3D reconstruction and length measurement is possible with dual image photogrammetry software allowing a precise determination both of the stretch zone width and height.