Diffusion and creep of Sr3(Ca1.18Nb1.82)O9−δ mixed Perovskite fabricated by melt processing

Compressive creep tests of Sr3(Ca1.18Nb1.82)O9−δ mixed Perovskite fabricated by melt processing were conducted in Ar and air to determine the deformation rate and to estimate the diffusion coefficient. At 1300-1350 °C, the steady-state strain rate (ε˙) could be expressed asε·=Aσ1.9±0.2exp⁡[(−670±94kJ/mole)/RT]where A is a constant, σ is the steady-state stress, R is the universal gas constant, and T is the absolute temperature. The data and microstructural observations indicated that the mechanism that controls plasticity is grain rotation associated with redistribution of the intercellular phase, accommodated by cell coalescence, due to diffusion and dislocations.