Nanoindentation, continuous load-depth

Continuous Load—Depth Recording. In ultramicroindentation and nanoindentation devices the displacement and load are monitored continuously. It should be possible to vary the applied load, or imposed displacement, either in ramp mode or with a discontinuous increment (step mode) (41). Figure 8 illustrates a loading-hold-unloading cycle obtained for PET using an... 

Althongh hardness derived from residual impression measurements is an indicator of the reversible plastic deformation processes, information about elastic release of the indentation depth is mostly lost. Continuous load-displacement monitoring (as the indenter is driven into and withdrawn from the film) sub-stitntes the imaging method nsed in conventional microindenters. The need to characterize the snrface of very thin films and near surfaces has led to the development of nltra- and nanoindentation testers with indentation depths within the submicrometer scale... 

Ultralow load indentation, also known as nanoindentation, is a widely used tool for measuring the mechanical properties of thin fdms and small volumes of material. The principle is to pushing in a hard material tip called the indenter into the analyzed sample and to measure the curve load-penetration. A modified commercial nanoindenter (Nano indenter XP - MTS) was used to characterize coated materials. The device allows to measure the contact stiffness with superimposing a harmonic oscillation (small amplitude of 3 nm, constant frequency of 32 Hz) to the continuous penetration of the indenter into the sample. This specificity allows one to continually measure the elastic modulus and hardness according to the penetration depth. Loubet et al. demonstrated that reduced Young modulus and hardness for a Berkovich indenter with a dynamic measurement method could be deduced from the following equations [11] ... 

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