Relationship of Stiffness-Based Indentation Properties Using Continuous-Stiffness-Measurement Method

摘要

The determination of elastic modulus ( ) and hardness ( ) relies on the accuracy of the contact area under the indenter tip, but this parameter cannot be explicitly measured during the nanoindentation process. This work presents a new approach that can derive the elastic modulus ( ) and contact depth ( ) based on measured experiment stiffness using the continuous-stiffness-measurement (CSM) method. To achieve this, an inverse algorithm is proposed by incorporating a set of stiffness-based relationship functions that are derived from combining the dimensional analysis approach and computational simulation. This proposed solution considers both the sink-in and pile-up contact profiles; therefore, it provides a more accurate solution when compared to a conventional method that only considers the sink-in contact profile. While the proposed solution is sensitive to Poisson’s ratio ( ) and the equivalent indentation conical angle ( ), it is not affected by material plasticity, including yield strength ( ) and work hardening ( ) for the investigated range of 0.001 < < 0.5. The proposed stiffness-based approach can be used to consistently derive elastic modulus and hardness by using stiffness and the load-and-unload curve measured by the continuous-stiffness-measurement (CSM) method.