On the Solidification of Metal Alloys during Microgravity Conditions

Thermal analysis and unidirectional solidification experiments of mainly Al-, Sn- and Pb-base alloys has been performed during Rocket Flights, Parabolic aircraft flights, Space Lab, and GAS- Shuttle flights over three decades. In this presentation the special equipments developed and the experimental results from the different flight opportunities are to be presented. The cooling rates in the theraml analysis experiments have varied from around 0.01 to 10 C/Sec. The coarsnes fo the structure has been evaluated and the main effect is an increase in coarsness with decreasing gravity. The solidification undercooling was measured and it was mainly lower during microgravity conditions. The microgravity conditions gave mostly a larger effective partition coeffecient.The result will be presented and shortly discussed from existing theoretical standpoints and the difference will be analysed.