The service life of cyclically loaded components is dominated by the stage of short crack growth. Therefore, investigations in this field are essential to understand the short crack growth of fatigue cracks.

Fundamental for this research are fatigue tests with so-called SEN specimens (Single-Edge-Notched Flat Specimen) with the hydraulically controlled testing machine ERIKA (fatigue crack propagation in corrosive atmosphere). The existing crack length can be calculated insitu with the help of a DC potential probe and can also be used directly for test control. For further information about the crack, the fracture surface is examined by light or electron microscopy to obtain information about the position and number of cracks and their coagulation.