Microstructure and mechanical properties of Li0.33La0.567TiO3

Abstract

Mechanical properties of conventional sintered Li0.33La0.567TiO3 (LLTO) are presented with focus on the correlation with the microstructural appearance. Variation in density, grain size, and second phase are achieved by changing the lithium to lanthanum ratio and sintering conditions. All samples show varying amounts of a second phase which is identified as TiO2. These inert particles have no effect on the measured mechanical properties. In contrast, a high sensitivity to changes in the microstructural evolution is found. Therefore, density and grain size are the important microstructural features to control both electrical and mechanical properties. For stoichiometric, a dense LLTO a Young’s modulus of 200 GPa, KIC of 1.2 MPam0.5, and a Vickers hardness of 8.4 GPa are measured. For all dense samples, the characteristic bending strength shows values around 150 MPa and Weibull modulus of m = 7–9. Deviations from these results are explained by microstructural events like second phases, density, or grain size.