DIRECTIONAL SOLIDIFICATION OF ALZN EUTECTIC IN MICROGRAVITY CONDITIONS

The directional solidification of an AlZn eutectic based on the Bridgman method has been carried out on the Earth and in orbit on the Russian orbital station in microgravity conditions on a CSK-1 apparatus developed at the Institute of Physics, Czech Academy of Sciences in Prague. From the conditions of growth - furnace rate 0.1 mm/min, axial temperature gradient in the melt approx. 5 K/cm - the study of the microstructure and the measurements of interlamellar spacing, lamellae thickness alpha(1), hardness HK and the anisotropy of linear thermal expansion it follows, that the microstructure of the specimens prepared in outer space shows an overall lower degree of directionality compared with specimens prepared in analogous terrestrial conditions.