Nanoindentation response of anisotropic piezoelectric materials

A three-dimensional finite element model is developed to accurately capture the force-depth and charge-depth nanoindentation response of several classes of anisotropic piezoelectric materials such as relaxor ferroelectrics for which analytical models are at present unavailable. Upon validating the finite element model for transversely isotropic materials, it is demonstrated that the nanoindentation response of anisotropic piezoelectric materials displays a strong dependence on the nature of the indenter geometry and relatively weak dependence on the indenter conductivity. Furthermore, by recourse to longitudinal and transverse indentations, the nanoindentation method can also be used to identify the poling directions in piezoelectric materials as well.