Computed tomography applied to the study of porosity in Al-Si castings

Abstract

X-ray computed tomography is a non-destructive analysis method that allows obtaining detailed information of the evaluated solid by post-processing three-dimensional images with special software. This work presents a methodology to evaluate porosity near the fracture zone in a sample of Al-Si cast iron, subjected to 3-point bending. 1106 pores were evaluated using 6 regions of interest (2 contain the fracture surfaces). Once the pores were analyzed, a technique was designed to obtain the normal stresses associated with the fracture. The results show that most of the pores have medium compactness values and the fracture surfaces show asymmetries in the overall pore count and in the small pore count. In this way, it will be possible to determine the mechanical strength in fractured components and, in addition, the normal stresses generated by external stresses in non-fractured components.