An alternative method for penetration depth determination in nanoindentation measurements

The information provided by the shape of the unloading portion of indentation curves is used to calculate the area of contact between the indenter and the material. Results obtained in fused silica and nickel, including Young's modulus and hardness values, are presented to illustrate the validity of the approach. It is shown that errors of only a few percent are introduced when fitting unloading curves with power laws. The present method is especially useful when direct specimen stiffness measurements can be performed.