Effect of domain structure on the damping properties of LiNbO3/Al composites

To study the possibility of utilizing piezoelectric effect, damping properties of poly- and single-domain LiNbO3 particle-filled pure aluminum composites were investigated by a dynamic mechanical thermal analyzer. The damping capacity of single-domain LiNbO3/Al composite is always higher than that of poly-domain LiNbO3/Al composite over the whole testing temperature range from 30 to 300 °C. At room temperature the single-domain LiNbO3/Al composite shows twice the damping capacity of the poly-domain LiNbO3/Al composite. Domain structures were observed by an optical microscope. Effect of the domain structure on the properties of LiNbO3 single crystal was studied based on the measurements of d33 piezoelectric constant, damping capacity and coefficient of thermal expansion (CTE). Then effect of the domain structure on the damping properties of the composites was investigated. The difference of the damping capacity between poly- and single-domain LiNbO3/Al composites is mainly attributed to the piezoelectric effect.