Microstructure and high-temperature mechanical behavior of melt-growth Al2O3/Er3Al5O12/ZrO2 ternary eutectic composites

The microstructural and high-temperature mechanical characteristics of directionally solidified rods of Al2O3-Er3Al5O12-ZrO2 ternary eutectic oxides processed by the laser-heated floating zone method at different growth rates have been investigated. The eutectic microstructure displayed an entangled three-dimensional network of Al2O3 and Er3Al5O12 phases of similar sizes, elongated along the growth direction; the minority zirconia phase formed small fibers into the alumina phase. The interphase spacing is reduced with increasing solidification rate, changing about 2 mu m down to 200 nm. These microstructural features are essentially the same exhibited by Al2O3-Y3Al5O12-ZrO2 composites processed by the same technique. Compressive deformation tests performed at 1400 degrees C at constant strain rate showed that the creep resistance decreased when increasing the growth rate due to the refinement of the microstructure. (c) 2012 Elsevier B.V. All rights reserved.