Investigation of particle dynamics and solidification in two phase system by neutron radiography

We investigate directional solidification of the melt with solid inclusions by means of neutron radiography (NR). As NR is a non-invasive imaging technique, the results, for the first time, reveal the particle trapping in the solidifying melt at macro scale. It is shown that particle solidification in volume can be achieved when liquid and solid phases form mushy zone. Experiments were performed using a rectangular vessel containing tin which was electromagnetically stirred and directionally solidified. Information about the recirculating flow was gathered by tracing 355-500 μm gadolinium (Gd) particles which visualize the flow field and phase composition in any given time. The findings show that metallurgical challenges, e.g. stirring and homogenously dispersing ceramic reinforcement material in MMC, could be solved by applying electromagnetic treatment while melt is in semi-solidus state.