Deflection of columnar grains during solidification of aluminium alloys under forced flow conditions

Abstract

Fluid flow strongly influences the grain morphology promoting growth of the columnar structure deflected towards the incoming flow. The effects of forced flow and initial superheat on columnar grain deflection of aluminium alloys were experimentally investigated in this work. The computer simulations of the flow with solidification included previously validated against experimental temperature measurements were used to interpret experimental results. It is shown that the deflection degree strongly depends on the inlet velocity, melt superheat, and alloy composition. Generally, the deflection angle increases with accelerated flow and at a higher superheat. Some quantitative correlations are obtained. Furthermore, several factors affecting the deflection of the grains are discussed.