LOW-TEMPERATURE CREEP OF NANOCRYSTALLINE TITANIUM(IV) OXIDE

Nanocrystalline TiO2 with densities higher than 99% of rutile has been deformed in compression without fracture at temperatures between 600-degrees and 800-degrees-C. The total strains exceed 0.6 at strain rates as high as 10(-3) s-1. The original average grain size of 40 nm increases during the creep deformation to final values in the range of 120 to 1000 nm depending on the temperature and total deformation. The stress exponent of the strain rate, n, is approximately 3 and the grain size dependence is d(-q) with q in the range of 1 to 1.5. It is concluded that the creep deformation occurs by an interface reaction controlled mechanism.