MICROSTRUCTURE AND CRYSTALLOGRAPHIC PHASE TEXTURES OF THE ALUMINA-ZIRCONIA EUTECTICS

Crystals of the Al2O3-ZrO2(Y2O3) eutectics were directionally solidifi ed by the Stepanov (EFG) technique. Microstructure and crystallographi c textures of phases in the crystals were investigated The [0001] crys tallographic orientation of the alumina matrix along the growth direct ion has been found to be a preferential one, independently of the seed crystal orientation. The zirconia phase demonstrated two different ty pes of crystallites: (i) whiskers in colonies, whose preferential orie ntation was [123] parallel to the crystal pulling direction and which were represented by the sharp peaks on the pole figures; (ii) coarse p articles in the intercolony spacing, whose preferential orientation wa s [110] parallel to the pulling direction and which was represented by more diffuse peaks. The six-fold symmetry was found in the [123] patt erns of cubic ZrO2 texture, which could only be a result of the couple d eutectic phase growth under the influence of the hexagonal alumina.