DIRECTIONAL SOLIDIFICATION OF ALZN EUTECTIC IN MICROGRAVITY CONDITIONS

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