Assessment of the fatigue behavior of non-porous surface layers in aluminium casting components based on the cyclic characteristic of the porous base material

The lifetime prediction for cast components often underestimates the actual lifetime. This is due to the fact that the material properties used for the calculation are determined by material specimens taken from the core of the components. This part of the components often contains imperfections. In the present article a model, which allows the evaluation of the S-N-Curve of this non-porous edge layer on the basis of the S-N-Curve of the porous base material, is introduced. The elastic-plastic behavior as well as the amount of porosity is taken into consideration. The alloys AlSi9Cu3 and AlSi10MgMnFe are used to validate the introduced model. The calculated S-N-Curves are in good correspondence with the experimentally ascertained results. The use of the calculated S-N-Curve in the computer aided fatigue simulation of an engine mount shows a substantially better correspondence with experimental data than former simulations.