Simulation of nanoindentation experiments of single‐layer and double‐layer thin films using finite element method

Abstract

In this work, we focused on investigations of mechanical properties of SiNx and diamond‐like carbon thin films deposited by plasma‐enhanced chemical vapour deposition method for application in optical devices or solar cells. Mechanical properties of thin films deposited on clean and oxidized silicon substrates were determined by nanoindentation. The main difficulty with the characterization of thin films using nanoindentation method is related to the influence of the substrate on the measured properties of thin layers. We proposed a method to determine the mechanical properties (hardness and Young's modulus) of thin films in single‐layer/substrate or double‐layer/substrate system through combining the finite element method, nanoindentation experiments and numerical simulations. In this study, a three‐dimensional numerical model of nanoindentation tests performed with Vickers diamond indenter was examined to determine the stress distributions during measurement with various maximum loads. The hardness and Young's modulus of the examined layers were determined using two types of procedures, depending on the von Mises equivalent stress distribution obtained at the maximum load. If the size of an elastically deformed region was sufficiently small compared with the thickness of the measured layers, we applied a standard method of measuring at the depth equal to 10% of the layer thickness; otherwise, an approximation method was used to reduce the substrate influence. Copyright © 2014 John Wiley & Sons, Ltd.

Elastic–plastic characterization of microstructures through pull-in 4 point bending test

“…However, the main limitations of this technique are the indentation depth, complex distribution of the indentation induced stresses and relatively costly experimental setup. Generally, FEM (finite element method) based simulations and analytical models are used to study the experimental load versus indentation depth curve and corresponding elastic-plastic stress distribution in thin films [30][31][32][33][34][35][36][37][38]. In addition to static tests, non-destructive dynamic tests based on the resonance frequency have also be implemented to evaluate the elastic behavior and residual stress in the thin films [39][40][41].…”

Comparison of structural, mechanical and corrosion properties of thin TiO 2 /graphene hybrid systems formed on Ti–Al–V alloys in biomedical applications

“…This is mainly due to the inability to define a correct and applicable area function for the indentation tip at very shallow penetration depths [25]. In our case, experiments have shown that the tip area function is not a significant source of error for indentations of contact depths larger than about 80 nm [26]. Unfortunately, for this indentation depth, the influence of the substrate on the measurement results is too big.…”

3D finite element simulation of scratch testing to quantify experimental failure mechanisms of a thin film

“…However, the distribution of these fields is difficult to determine experimentally since several phenomena are involved in the scratch test, such as elastoplasticity, fracture, and wear caused by the excessive deformations on the sample [22,23]. Theoretical models can predict the stresses generated by scratching, where the complex deformation at the indenter-surface contact has been reproduced using numerical simulation with high correspondence to the actual phenomena [23][24][25][26][27][28][29][30][31][32][33][34][35]. The finite element (FE) method is a suitable tool for understanding the behavior of the stress-strain field [24].…”

“…Modeling the scratch process of thin films using FE has been used to understand the different types of damage on film-substrate systems [25][26][27]. For instance, the plastic deformation zone under the indenter tip has been assessed through the Von Mises criterion, even when the studied film presented a brittle behavior [28,29]. However, the differences between the brittle and ductile behaviors of the film-substrate system require a theory that considers such mechanical variations during the analysis of scratch tests.…”