Optimum strain state for oxygen diffusion in yttria-stabilised zirconia

The strain effect of the oxygen diffusion in the yttria-stabilised zirconia in the present study was investigated by means of a molecular dynamics simulation. The simulation was conducted for various parameters such as the strain, temperature, yttria concentration, and potential parameter, and in addition, the biaxial and hydrostatic cases were considered. For a uniaxial strain, the oxygen diffusion was enhanced in the tensile direction whereas it was hindered in the compressive direction. The maximum improvement was achieved for a smaller strain at a lower temperature and also with a lower yttria concentration. For the biaxial and hydrostatic strains, the total diffusion coefficient was enhanced simply as a result of the enhancement when using the uniaxial strain in each direction. The detailed deformation analysis reveals that the optimum strain state for the highest oxygen diffusion in the tensile direction can be obtained when the oxygen ion is largely displaced in the fluorite lattice structure.