Temperature and pressure dependence of phase evolution in 0.5 MgO-0.5 Y2O3 is studied using the diamond anvil method. At 300 K and 5.5 GPa, transformations in Y2O3 are observed, resulting in co-existence of cubic, hexagonal, and monoclinic phases. Heating to 1293 K results in increased crystallinity and increase in hexagonal and monoclinic phase content. Isothermal and isobaric hold at 1273 K and 5.5 GPa for 120 min results in yttrium dissolution in cubic MgO, causing 0.83 volumetric strain. Cooling to 300 K and 0 GPa yields a four phase co-existence among cubic MgO and cubic, hexagonal, and monoclinic Y2O3. The residual MgO unit cell volume expansion is 0.67 at 300 K, indicating solid solution formation. Aging of the nanocomposites for 240 h does not change the observed 4 phase co-existence.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)