Theoretical model for determining elastic modulus of ceramic materials by nanoindentation

In order to accurately determine the mechanical properties of ceramic materials with small size specimens by the nanoindentation experiment, an effective work ratio of indentation method is proposed based on the dimensional analysis and finite element simulation to extract elastic modulus of ceramic materials from sharp indentation load-displacement data. Results indicate that the influence of strain hardening exponent of materials on elastic modulus is very weak and can be ignored in this model. Moreover, the elastic modulus of the investigated material can be expressed as a simple function of the work ratio of indentation, plane strain elastic modulus of the indenter, as well as the nominal hardness of the investigated material. Additionally, the effectiveness and accuracy of this proposed method were verified by instrumented indentation tests on two typical certified standard fused silica and borosilicate crown glass samples with Berkovich indenter. After comparison with conventional Oliver-Pharr method, it is shown that the work ratio of indentation method has advantages including high accuracy and small standard deviation.