|About this Abstract
||2017 TMS Annual Meeting & Exhibition
||Fracture Properties and Residual Stresses in Small Dimensions
||Orientation Dependent Fracture Behaviour of LiTaO3 and LiNbO3 Single Crystals
||Manuel Gruber, Raul Bermejo, Jeroen Bielen, Peter Supancic, Robert Danzer, Daniel Kiener
|On-Site Speaker (Planned)
Single crystal piezoelectric materials such as LiTaO3 and LiNbO3 have found important application as surface acoustic wave filter substrates for high frequency data transfer. In order to optimize the functionality of the filters, a particular orientation and surface conditioning (e.g. grinding) of the crystal must be ensured. This can affect the mechnical response of the functional material to external thermo-mechanical loading.In this work, the strength and crack growth resistance (fracture toughness) of LiTaO3 and LiNbO3 materials were investigated macroscopically using biaxial bending and microscopically by miniaturized V-notched cantilevers in a SEM, respectively. It was found that the orientation of the notch, either parallel to the corresponding cleavage plane or with an angle, yields to a significant difference in the toughness values. As a consequence, the orientation of the grinding directions during flexural bending with respect to the cleavage planes showed a high impact on the strength for both materials.