Indenter tip radius and load frame compliance calibration using nanoindentation loading curves

The finite-element method has been used to simulate the indentation process of a variety of isotropic elastic-plastic materials indented by a rigid co nical indenter with a perfectly sharp tip and round tips of various radii. Analyses of the obtained loading curves showed that the load frame complian ce C-f of the nanoindentation instrument and the tip roundness r of the ind enter can be determined from the loading curve. In a real indentation exper iment, the obtained raw load-depth data during the loading stage can be des cribed by the second-order polynomial dependence of depth on the square roo t of load, from which the C-f and r Values are determined. An experimental procedure has thus been proposed for C-f and r calibration using the loadin g curves of a hard and isotropic material. Nanoindentation experiments on f used silica demonstrate the reliability of the proposed technique for accur ate and quick C-f and r calibration.