Modeling of the influence of pore morphology on damage behavior of an aluminum die casting alloy

The analysis of deformation and damage behavior of aluminum cast components is very complex, since local mechanical properties in the components are inhomogeneous as a consequence of spatial distribution of microstructure e.g. pore size, grain size and arm spacing of secondary dendrites. Moreover, the damage behavior of aluminum alloys depends strongly on stress state. Until now it is not clear how the pore morphology affects the damage behavior under different loading situations. In this work the damage behavior of the aluminum die casting alloy AlSi9Mn was characterized with tension specimens extracted from different positions in a component. Damage effect was modeled with representative volume elements (RVE) with variation of porosity, pore size and distribution of pores under uniaxial and biaxial tension, plane strain, compression and shear. Not only pore growth and coalescence but also damage of the matrix material was taken into account in the simulations. A large influence of pore morphology on fracture strain was found and relationships between fracture strain and pore morphology were proposed for different stress states.