Local order and thermal conductivity in yttria-stabilized zirconia. I. Microstructural investigations using neutron diffuse scattering and atomic-scale simulations

This paper is the first of a couple of papers intended to study the lattice thermal conductivity of yttria-stabilized zirconia. It is dedicated to the microstructural aspects. The out-of-equilibrium local order of the single crystal samples was characterized through neutron diffuse scattering. A Monte Carlo code was developed in order to simulate the state of the samples. This code uses position-dependent potentials found in literature. The reliability of the simulated microstructure is then evaluated by comparison with our neutron measurements. The kinetics aspects were treated through the characterization of the local order associated with the tetragonal phase which develops for different heat treatments near 10 mol % Y₂O₃. The short-range order is interpreted as an incipient ordering of the tetragonal type below 10 mol % Y₂O₃, and of the δ phase type for higher defect concentrations. The Monte Carlo configurations are used as starting configurations for the companion paper, dedicated to simulations of the lattice thermal conductivity by a nonequilibrium molecular dynamics approach.