Molecular dynamics study on oxygen diffusion in yttria-stabilized zirconia subjected to uniaxial stress in terms of yttria concentration and stress direction

In the present study, the oxygen diffusion in 4, 8, and 14 mol%-yttria-stabilized zirconia (4, 8, and 14YSZ) subjected to the uniaxial stresses in the [100], [110], and [111] directions is investigated by the molecular dynamics simulation. In the case of the uniaxial stress in the [100] direction, the oxygen diffusion in 4YSZ and 8YSZ is facilitated in the tensile direction and deteriorated in the compressive direction without changing the total diffusion property, which could be caused by the elastic recovery force. For 14YSZ, however, the oxygen diffusion remains unchanged regardless of the stress, probably due to the high yttria concentration. In the cases of the tensile stress in the [110] and [111] directions, the oxygen diffusion is also increased in the tensile direction, which could be attributed to the improvement of the oxygen diffusion in the < 100> direction caused by the stress component in the < 100> direction. The tensile stress component in the < 100> direction, therefore, could facilitate the oxygen migration in yttria-stabilized zirconia with the lower yttria concentrations.