Stable and Metastable Phase Relations in the System Alumina-Zirconia-Yttria

The Al2O3ZrO2Y2O3 system was studied in the range of temperatures 1600°–2800°C by methods of X‐ray analysis at 20°C, petrography, DTA in He at temperatures to 2500°C, thermal analysis in air using a solar furnace at temperatures to 3000°C, and electron microprobe X‐ray analysis. The stable and metastable phase diagrams were constructed. The liquidus and solidus projections, crystallization paths for the alloys, and polythermal sections are presented in the article. The structure of the restricting systems defines the phase equilibria in the ternary system. No ternary compounds were found. The metastable phase relations were caused by the ambivalent behavior of Y3Al5O12 during crystallization.