Effect of Pores on Tensile Fracture of Die-cast AlSiMgMn alloys with 3D X-ray μ-CT and FE Simulation

In this study, the pores in die-cast AlSiMgMn alloys were inspected and reconstructed with high resolution three-dimensional (3D) X-ray micro computed tomograpgy (mu-CT) technique. Finite element (FE) meshes were built with consideration of the pore actural morphorloges from the CT inspection. Based on dutile damage model, the FE simulation of tensile fracture of the alloys was carried out. The simulation results were compared and verified with the tensile of in-situ scanning electron microscopy (SEM). The two results are agreement in the main crack path and pores on the fracture. With the pore-scale simulation, the effects of pore characteristics on the stress distributions and crack initiation and growth during the tensile were analyzed. It was found that the pores of lower sphericity and larger project area in tensile axis direction are prone to form microcracks and promote main crack deflection. The results also show that aggregation of brittle alpha-Fe intermetallics of the alloys also has important influence on the main crack propagation.