Mechanism of eutectic growth in directional solidification of an Al2O3/Y3Al5O12 crystal

The Al2O3/Y3Al5O12 eutectic crystal was prepared by an optical floating zone furnace. The grain selection process and competitive growth mechanism of eutectic crystal during directional solidification were investigated byelectron backscattered diffraction and high resolution transition electron microscopy. We found that the interfacial relationships of Al2O3 and YAG were parallel while their growth directions were not, and interfacial energy played a predominant role in controlling the solidification behavior of the Al2O3/Y3Al5O12 eutectic crystal. The competitive growth behavior between [11(1) over bar] and [011] of Y3Al5O12 grains was well discussed. A growth model of the Al2O3/Y3Al5O12 eutectic growth was proposed based on the microstructure evolution. (C) 2016 Elsevier Ltd. All rights reserved.