Role of Interdendritic Fluid Flow on the Porosity Formation in A206 Alloy Plate Castings

Abstract

Porosity formation in A206 aluminum plate castings was studied experimentally and theoretically. The experimental results indirectly confirm the roles of interdendritic liquid metal flow which causes a local pressure drop within the interdendritic liquid in accordance with the Darcy's law. A solidification feeding efficiency index, denoted as G 0.4 /V s 1.6 (G is the thermal gradient and V s is the solidus velocity), is employed to estimate the value of local pressure drop during solidification process and to predict the formation of porosity in A206 alloy castings. That the influence of the index is more prominent at a longer local solidification time than at a shorter local solidification time is also supported by the experiment