Abstract
In order to clarify the influence of gravity on solidifying the metal, a copper is solidified under rapid cooling in µg by using a drop shift. A cooling system consisting of carbon crucible and copper block inserting with tin powder is
constructed for solidifying rapidly the copper sample in the crucible. The macro-structure of the solidified copper in 1 g shows that the grains grow toward the upside of center of the sample by particular orientation, whereas the orientation of the grains in µg is random. Cooling curves are measured at 0, 2 and 5 mm from the sample bottom in µ g. The shapes of them are different from the curves measured in 1 g. The temperature at 5 mm drops gradually without a constant period. The results in µg suggest that the convection in a liquid copper sample is little, and the gravity affects the solidification process even under the rapid cooling.
