Size effects in nanoindentation: an experimental and analytical study

This work addresses the size effect encountered in nanoindentation experiments. It is generally referred to as the indentation size effect (ISE). Classical descriptions of the ISE show a decrease in hardness for increasing indentation depth. Recently new experiments have shown that after the initial decrease, hardness increases with increasing indentation depth. After this increase, finally the hardness decreases with increasing indentation. This work reviews the existing theories describing the ISE and presents new formulations that incorporate the hardening effect into the ISE. Furthermore, indentation experiments have been performed on several metal samples, to see whether the hardening effect was an anomaly or not. Finally, numerical simulations are performed using the commercial program ABAQUS.