Directional solidification of eutectics: New prospects for refractory oxide cermaics (review)

Conclusions The directional solidification of the eutectic in the refractory oxide systems results in the formation of a plate-shaped or fibrous oriented composite structure. The theoretical fundamentals of the method of directionally solidified eutectics, developed on the basis of the metallic systems, can also be applied extensively to refractory oxide DSEs so that their structure and composition can be controlled in the required direction.The orientation relations between the phases of the refractory oxide DSEs and the construction of the interphase boundaries result in the formation of semicoherent interphase boundaries. This is one of the conditions for the higher and thermal stability of the materials.The mechanical properties of the materials based on refractory oxide DSEs are controlled by the structure of the oriented eutectic. Disruption of flat frontal growth in solidification leads to the formation of a cellular structure. The cell boundaries are the weakest area of the material and control its behavior during failure.The materials based on the direction solidified refractory oxide eutectics have unique set of the applied properties and are highly promising for use as structural materials at elevated (up to 1500°C) temperatures.The materials made of the refractory oxide DSEs can be used in practice after developing high-productivity methods of their growth which would make it possible to produce components of the required shape.Translated from Poroshkovaya Metallurgiya, No. 8(320), pp. 58–69, August, 1989.