Tracking Nanoindentation Tip Wear

Nanoindentation is a common technique to measure the mechanical behavior of materials with emphasis on a small probing volume, useful especially for thin films and micro-composite materials. The technique relies on calibrating the area function of the pyramidal tip. Users are well aware that the tip area function can change over time, thus the need to be frequently recalibrated. The change in area function aligns with a change in the tip radius blunting. It is important to not only have a well-calibrated tip for accurate results but also knowledge of the tip radius which can aid in the identification of deformation mechanisms or anomalous data, and it governs the actual strain concentration under the tip. Long-term radius evolution of three Berkovich diamond tips will be presented illustrating that tip wear can be easily tracked and generally occurs in three stages: stable, blunting, and resharpening. The results also demonstrate that the indented material and the amount of scanning (height-imaging with tip in contact) are factors that could lead to faster tip blunting.