Piezoelectric Actuator-Based Nanoindentation

Abstract

In this article we report a novel depth-sensing nanoindenter using a lead zirconium titanate (PZT) stack actuator to measure the Young's modulus of Titanium composite. The nanoindenter uses an open-loop positioning control scheme with displacement sensors. In general, the conventional nanoindenters require closed-loop controls for precise loading of the indenter tip. The developed open-loop control scheme compensates for the hysteresis and the creep errors of PZT actuators. We have shown that the overall system structure can be simplified and a high positioning repeatability can be achieved. To verify the system performance, we conducted the indentation tests on titanium matrix composite surfaces. Besides the basic nanoindentation functions, the developed system also has the capability for surface imaging through a scanning function. The pre-indentation scanning capability proved to be a very useful method for positioning the tip in the desired indentation location. Similarly, post-indentation scanning allows for visualization of the indentation marks after the tests.