Determination of the contact area is a key issue for extracting the mechanical properties from the analysis of nanoindentation load-displacement (P-h) curves. In this paper, a new method for the direct determination of the contact area with the empirical equation A = C (Hc + Hd) ^2 was proposed. It is based on the consideration of round indenter tip correction, using the correction factor Hd yielded by fitting the loading segment of the measured P-h curve and the contact depth Hc determined from the unloading segment of the same curve. Thus, the mechanical properties can be extracted easily and directly without the need of the pre-calibration of area function. The applicability of this new method was examined by statistical analysis of a total of 497 nanoindentation tests performed on silica glass. It was shown that reliable results of Young’s modulus and hardness can be obtained based on the proposed new method.
Guo et al. (Thu,) studied this question.