Initial Evaluation of the Fracture Behavior of Piezoelectric Single Crystals Due to Artificial Surface Defects

This study is part of a new research program to develop fundamental understanding of the fracture and fatigue behavior of piezoelectric single crystals through the combination of computational and experimental approaches. In this work we present 1) experimental results on the creation of artificial surface defects in piezoelectric single crystals using a focused ion beam (FIB) system and 2) initial observations on the crystal's fracture behavior under an electrical field. The major advantage of using a FIB is that one can control the size, shape, and orientation of artificial defects precisely, allowing realistic surface defects, e.g., half-penny-shaped, 100 mum long, <1 mum wide, and 50 mum deep. We have demonstrated that multiple artificial defects with varying inclination angles relative to the specimen's crystallographic orientation can be machined in a few hours. In this paper, we report the experimental details of the FIB milling, typical defect shape, and initial results on the effects of high electric field on the fracture behavior of single crystals.