Compressive creep of YBa_2Cu_3O_x

YBa 2 Cu 3 O x was deformed from 850 to 980 °C in oxygen partial pressures of 10 3 to 10 5 Pa. Steady-state creep rate, , for P (O 2 ) from 10 4 to 10 5 Pa could be expressed as = Aσ 1.0 (GS) −2.8±0.6 exp −(970 ± 130 kJ/mole)/R T , where A is a constant, σ the steady-state stress, GS the average grain size, and R and T have their usual meanings, For P (O 2 ) from 10 3 to 3 ⊠ 10 3 Pa, the activation energy decreased to about 650 kJ/mole and for a given temperature creep kinetics were much faster. The data and microscopic observations indicated that creep occurred by diffusional flow. Comparisons with diffusion data for YBa 2 Cu 3 O x suggested that Y or Ba may be rate-controlling diffusing species.

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