Ductile mode machining of piezoelectric single crystal by laser-assisted diamond turning process

Abstract

Piezoelectric single crystals are multifunctional materials used in advanced ultrasound devices owing to their exceptional piezoelectric properties. Nevertheless, machining methods for these single crystals have been limited due to their brittle nature and material deterioration issues. Herein, we established a ductile machining process of piezoelectric single crystal based on a laser-assisted diamond turning process through comprehensive analysis. In order to achieve defect-free surfaces, we analyzed the cutting behavior of softened piezoelectric single crystals concerning crystal orientation and machining direction. The experimental studies examined the effects of processing parameters on mechanical, chemical, crystallographic, and piezoelectric properties. The cutting status was characterized by measuring acoustic emission signals and analyzing the cutting chip formation. By optimizing the process and establishing a ductile mode of diamond turning mechanisms of piezoelectric material, we machined the brittle single crystal into various shapes, such as double-sided and multi-scale microstructure, without showing any defects all over the crystal orientation. We also demonstrated the validity of the machining process for piezoelectric material through an ultrasound characteristic test, which showed that the fabricated ultrasound transducers with machined single crystal maintained ultrasonic performance without deterioration in underwater experiments.