Evaluating Micromechanical Properties at Surfaces Using Nanoindentation With Finite-Element Modeling

Author(s):  
J. A. Knapp ◽  
D. M. Follstaedt ◽  
S. M. Myers

Detailed finite-element modeling of nanoindentation data is used to obtain accurate mechanical properties of very thin films or surface-modified layers independently of the properties of the underlying substrates. These procedures accurately deduce the yield strength, elastic modulus, and layer hardness, and greatly increase the usefulness of indentation testing with very thin surface layers. Moreover, extraction of the effective Young’s modulus in the near surface region should enable mechanical damage studies on a small scale. This paper presents a brief overview of the procedures involved and illustrates them with He-implanted Ni.

1996 ◽  
Vol 438 ◽  
Author(s):  
J. A. Knapp ◽  
D. M. Follstaedt ◽  
J. C. Barbour ◽  
S. M. Myers ◽  
J. W. Ager ◽  
...  

AbstractWe present a methodology based on finite-element modeling of nanoindentation data to extract reliable and accurate mechanical properties from thin, hard films and surface-modified layers on softer substrates. The method deduces the yield stress, Young's modulus, and hardness from indentations as deep as 50% of the layer thickness.


1996 ◽  
Vol 444 ◽  
Author(s):  
S. M. Myers ◽  
D. M. Follstaedt ◽  
J. A. Knapp ◽  
T. R. Christenson

AbstractDual ion implantation of titanium and carbon was shown to produce an amorphous surface layer in annealed bulk nickel, in electroformed Ni, and in electroformed Ni7 5Fe 2 5. Diamond-tip nanoindentation coupled with finite-element modeling quantified the elastic and plastic mechanical properties of the implanted region. The amorphized matrix, with a thickness of about 100 nm, has a yield stress of approximately 6 GP and an intrinsic hardness near 16 GPa, exceeding by an order of magnitude the corresponding values for annealed bulk Ni. Implications for micro-electromechanical systems are discussed.


2018 ◽  
Vol 773 ◽  
pp. 3-9 ◽  
Author(s):  
Ilya A. Morozov ◽  
Anton Y. Beliaev ◽  
Roman I. Izyumov

Stiff coating on the phase-separated soft polyurethane substrate under the compression deformation is investigated by the finite element modeling (FEM). External strain leads to the wrinkling of layer surface, which is characterized by a set of wavelengths and amplitudes. The influence of the thickness and stiffness of the layer, elastic modulus of the substrate on the structural-mechanical properties of the deformed surface is studied. The results of the model are in good accordance with the experiment (plasma immersion ion impanation of nitrogen ions into the polyurethane substrate) and allowed to estimate the modulus of the coating and the deformation of the surface.


1999 ◽  
Vol 593 ◽  
Author(s):  
P.J. Wolff ◽  
B.N. Lucas ◽  
E.G. Herbert

ABSTRACTA commonly used technique to compute mechanical properties from indentation tests is the Oliver and Pharr method. Using dimensional analysis and finite element modeling, this paper investigates errors when the Oliver and Pharr method is used to compute thin film properties.


2004 ◽  
Vol 19 (1) ◽  
pp. 218-227 ◽  
Author(s):  
J.A. Knapp ◽  
D.M. Follstaedt

Thin-film mechanical properties can be measured using nanoindentation combined with detailed finite element modeling. This technique was used for a study of very fine grained Ni films, formed using pulsed-laser deposition on fused silica, sapphire, and Ni substrates. The grain sizes in the films were characterized by electron microscopy, and the mechanical properties were determined by ultra-low load indentation, analyzed using finite element modeling to separate the mechanical properties of the thin layers from those of the substrates. Some Ni films were deposited at high temperature or annealed after deposition to enlarge the grain sizes. The observed hardnesses and grain sizes in these thin Ni films are consistent with the empirical Hall–Petch relationship for grain sizes ranging from a few micrometers to as small as 10 nm, suggesting that deformation occurs preferentially by dislocation movement even in such nanometer-size grains.


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