Creep resistance of directionally solidified ceramic eutectics of Al203/c-Zr02 with sub-micron columnar morphologies

Directionally solidified laser float-zone-processed ceramic eutectics, having columnar morphologies made up of colonies of fibrilar and lamellar components of cubic Zr02 surrounded by a component of Al203 and having sub-micron morphological wave length, have a potential for remarkable creep resistance in the 1400°C temperature range when stressed parallel to the growth direction. The bulk creep response of both single crystalline Al203 and cubic Zr02 have been investigated extensively at this temperature and have shown no extraordinary promise for structural application. However, when directionally solidified and constituted in columnar eutectic morphologies with sub-micron wave length of phase dimensions, the restricted plasticity behavior that should occur can result in remarkable creep resistance. In many respects, this topology of constrained plasticity is expected to resemble that found in the CMSX-III super alloy single crystals.