Formation and distribution of entrainment defects in gravity AISi7Cu0.5Mg alloy castings

In this study, the formation of entrainment defects in gravity permanent mould casting process was experimentally and numerically investigated. The distribution of oxide inclusions was mapped at the microscopic scale using metallographic and image analysis techniques. A fluid-dynamic simulation commercial software was used to predict the formation of defects and air entrapment during the casting process. The results showed that the typical casting defects detected throughout the castings were generated by the entrainment of bifilms. Moreover, the good agreement between the numerical results and the experimental findings proved that the numerical models had successfully predicted the entrainment phenomena, especially the formation of oxide inclusions and the entrapment of air bubbles.