Determination for elasticity and plasticity from time-dependent nanoindentations

Indentation experiments of five metallic and one polymer materials were conducted by applying two pyramidal indenters under different operation conditions. All load–depth responses showed rate-dependent behaviors in various degrees. A combined method, based on the analyses developed for elastic–plastic responses of pyramidal indentations, was proposed for analyzing time-dependent indentation. Application of the combined method determined the material properties of elastic modulus and true hardness when loading and unloading coefficients and indenter inclined angle were given. For rate-dependent responses, the quasi-steady loading and unloading coefficients were determined by proper processing of h/P0.5 and P/S2 parameters, respectively. All material properties of tested materials, which were obtained from Berkovich and cube-corner indentations, are quite close to the reported values.