Numerical study on the measurement of thin film mechanical properties by means of nanoindentation

2001 ◽  
Vol 16 (10) ◽  
pp. 2974-2982 ◽  
Author(s):  
Xi Chen ◽  
Joost J. Vlassak
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Mechanical Properties ◽  
Finite Element Method ◽  
Finite Element ◽  
Numerical Study ◽  
Substrate Effect ◽  
The Finite Element Method ◽  
Effect Factor ◽  
A New Technique

Nanoindentation is a technique commonly used for measuring thin film mechanical properties such as hardness and stiffness. In this study, we used the finite element method to investigate the effect of substrate and pileup on hardness and stiffness measurements of thin film systems. We define a substrate effect factor and construct a map that may be useful in the interpretation of indentation measurements when it is not possible to make indentations shallow enough to avoid the influence of the substrate on the measurements. A new technique for measuring mechanical properties of thin films by nanoindentation is suggested at the end of this article.

A Finite Element Study on the Nanoindentation of Thin Films

2000 ◽  
Vol 649 ◽  
Author(s):  
Xi Chen ◽  
Joost J. Vlassak
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Finite Element ◽  
Film Thickness ◽  
Substrate Effect ◽  
The Finite Element Method ◽  
Effect Factor ◽  
Pile Up ◽  
Key Factor ◽  
Elastic Mismatch

ABSTRACTNanoindentation is a technique commonly used for measuring thin film mechanical properties such as hardness and stiffness. Typically, shallow indentations with contact depths less than 10-20% of the film thickness are used to ensure that measurements are not affected by the presence of the substrate. In this study, we have used the finite element method to investigate the effect of substrate and pile-up on hardness and stiffness measurements of thin film systems. We find that: i) for soft films on hard substrates, the hardness is independent of the substrate as long as the indentation depth is less than 50% of the film thickness; ii) as soon as the hardness exceeds that of the substrate, the substrate effect becomes significant, even for indentations as shallow as 5% of the film thickness; iii) if the film is at least 40 times harder than the substrate, the plastic zone is mostly confined to the substrate while the film conforms to the deformed substrate by bending. We define a substrate effect factor and construct a map that may be useful in the interpretation of indentation measurements on thin films. It is found that the yield stress mismatch is a key factor characterizing the hardness of thin film system, and the elastic mismatch is important when making stiffness measurements. The results obtained in this study are very useful when it is difficult to avoid the influence of the substrate on the measurements.

Analysis of the accuracy of the bulge test in determining the mechanical properties of thin films

1992 ◽  
Vol 7 (6) ◽  
pp. 1553-1563 ◽  
Author(s):  
Martha K. Small ◽  
W.D. Nix
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Mechanical Properties ◽  
Finite Element ◽  
Material Properties ◽  
Deformation Behavior ◽  
Initial Conditions ◽  
Standard Technique ◽  
Bulge Test ◽  
The Finite Element Method

Since its first application to thin films in the 1950's the bulge test has become a standard technique for measuring thin film mechanical properties. While the apparatus required for the test is simple, interpretation of the data is not. Failure to recognize this fact has led to inconsistencies in the reported values of properties obtained using the bulge test. For this reason we have used the finite element method to model the deformation behavior of a thin film in a bulge test for a variety of initial conditions and material properties. In this paper we will review several of the existing models for describing the deformation behavior of a circular thin film in a bulge test, and then analyze these models in light of the finite element results. The product of this work is a set of equations and procedures for analyzing bulge test data that will improve the accuracy and reliability of this technique.

Modified Stoney's Equation for Evaluation of Residual Stresses on Thin Film

2015 ◽  
Vol 789-790 ◽  
pp. 25-32
Author(s):  
Kuen Tsann Chen ◽  
Jui Hsing Chang ◽  
Jiun Yu Wu
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Finite Element Method ◽  
Finite Element ◽  
Residual Stresses ◽  
Present Method ◽  
Neutral Axis ◽  
The Finite Element Method ◽  
Simple Method ◽  
Material Parameters

In the article, a simple method for the modification of the Stoney's equation was presented. The Stoney's equation is proposed from the assumption of equi-biaxial residual stresses in thin films. In this present method, biaxial stresses are different in x-axis and y-axis on thin film. The location of neutral axis depends on the material parameters and the film thickness. The finite element method (FEM) was used to simulate the thermal stress on the thin film. The results of the modified methods are compared with the results of FEM and other literatures. The present method is more accurate than the Stoney's equation in the evaluation of such films.

Mechanical deflection of cantilever microbeams: A new technique for testing the mechanical properties of thin films

1988 ◽  
Vol 3 (5) ◽  
pp. 931-942 ◽  
Author(s):  
T. P. Weihs ◽  
S. Hong ◽  
J. C. Bravman ◽  
W. D. Nix
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Mechanical Properties ◽  
Single Layer ◽  
Beam Theory ◽  
New Technique ◽  
Young’S Moduli ◽  
Silicon Micromachining ◽  
A New Technique

The mechanical deflection of cantilever microbeams is presented as a new technique for testing the mechanical properties of thin films. Single-layer microbeams of Au and SiO2 have been fabricated using conventional silicon micromachining techniques. Typical thickness, width, and length dimensions of the beams are 1.0,20, and 30 μm, respectively. The beams are mechanically deflected by a Nanoindenter, a submicron indentation instrument that continuously monitors load and deflection. Using simple beam theory and the load-deflection data, the Young's moduli and the yield strengths of thin-film materials that comprise the beams are determined. The measured mechanical properties are compared to those obtained by indenting similar thin films supported by their substrate.

scholarly journals Influence of the Mechanical Properties of Elastoplastic Materials on the Nanoindentation Loading Response

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4842
Author(s):  
Huanping Yang ◽  
Wei Zhuang ◽  
Wenbin Yan ◽  
Yaomian Wang
Keyword(s):  
Mechanical Properties ◽  
Finite Element Method ◽  
Finite Element ◽  
The Other ◽  
Equivalent Model ◽  
Strain Hardening Exponent ◽  
Mechanical Parameters ◽  
The Finite Element Method ◽  
Fem Simulations ◽  
Elastoplastic Materials

The nanoindentation loading response of elastoplastic materials was simulated by the finite element method (FEM). The influence of the Young’s modulus E, yield stress σy, strain hardening exponent n and Poisson’s ratio ν on the loading response was investigated. Based on an equivalent model, an equation with physical meaning was proposed to quantitatively describe the influence. The calculations agree well with the FEM simulations and experimental results in literature. Comparisons with the predictions using equations in the literature also show the reliability of the proposed equation. The investigations show that the loading curvature C increases with increasing E, σy, n and ν. The increase rates of C with E, σy, n and ν are different for their different influences on the flow stress after yielding. It is also found that the influence of one of the four mechanical parameters on C can be affected by the other mechanical parameters.

scholarly journals Analysis of the Functionally Step-Variable Graded Plate Under In-Plane Compression

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4090 ◽  
Author(s):  
Leszek Czechowski ◽  
Zbigniew Kołakowski
Keyword(s):  
Mechanical Properties ◽  
Finite Element Method ◽  
Finite Element ◽  
Functionally Graded ◽  
The Finite Element Method ◽  
Graded Materials ◽  
Number Of Layers ◽  
Critical Equilibrium ◽  
Post Buckling ◽  
Plane Compression

A study of the pre- and post-buckling state of square plates built from functionally graded materials (FGMs) and pure ceramics is presented. In contrast to the theoretical approach, the structure under consideration contains a finite number of layers with a step-variable change in mechanical properties across the thickness. An influence of ceramics content on a wall and a number of finite layers of the step-variable FGM on the buckling and post-critical state was scrutinized. The problem was solved using the finite element method and the asymptotic nonlinear Koiter’s theory. The investigations were conducted for several boundary conditions and material distributions to assess the behavior of the plate and to compare critical forces and post-critical equilibrium paths.

Sign in / Sign up

Export Citation Format

Share Document