<title>Determination of fracture toughness of piezoceramics under the influence of electric field using Vickers indentation</title>

Abstract

Vickers indentation is a popular method for determining fracture toughness of brittle materials. Although this method depends on an empirical formula relating the stress intensity factor (or toughness) to the indentation parameters, it is simple and economical. In this study, the Vickers indentation method was used to determine the apparent fracture toughness of PZT- 4 piezoceramic under the influence of electric fields. The mechanical strain energy release rate associated with the crack produced by the Vickers indentor was derived. Using the analytical mechanical strain energy release rate for an infinite piezoelectric medium with a center crack and far field in-plane mechanical and electrical loadings, the mechanical strain energy release rate was obtained for Vickers indentation, which involves the out-of-plane indentation load. The effect of the electric field is properly included. The accuracy of the proposed formula was verified by experimental results.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.