Anisotropic elastic properties of nanocrystalline nickel thin films

2005 ◽  
Vol 20 (5) ◽  
pp. 1186-1193 ◽  
Author(s):  
D.C. Hurley ◽  
R.H. Geiss ◽  
M. Kopycinska-Müller ◽  
J. Müller ◽  
D.T. Read ◽  
...  
Keyword(s):  
Elastic Properties ◽  
Transversely Isotropic ◽  
Acoustic Microscopy ◽  
Indentation Modulus ◽  
Polycrystalline Nickel ◽  
Nickel Thin Films ◽  
Microtensile Testing ◽  
Measurement Results ◽  
Oriented Polycrystalline ◽  
Anisotropic Elastic

The elastic properties of a nickel film approximately 800 nm thick were measured with nanoindentation, microtensile testing, atomic force acoustic microscopy (AFAM), and surface acoustic wave (SAW) spectroscopy. Values for the indentation modulus (220–223 GPa) and Young’s modulus (177–204 GPa) were lower than predicted for randomly oriented polycrystalline nickel. The observed behavior was attributed to grain-boundary effects in the nanocrystalline film. In addition, the different measurement results were not self-consistent when interpreted assuming elastic isotropy. Agreement was improved by adopting a transversely isotropic model corresponding to the film’s 〈111〉 preferred orientation and reducing the elastic moduli by 10–15%. The SAW spectroscopy results indicated that the film density was 1–2% lower than expected for bulk nickel, consistent with models for nanocrystalline materials. Similar reductions in modulus and density were observed for two additional films approximately 200 and 50 nm thick using AFAM and SAW spectroscopy. These results illustrate how complementary methods can provide a more complete picture of film properties.

Specimen Specific Multiscale Model for the Anisotropic Elastic Properties of Human Cortical Bone Tissue

2007 ◽  
Author(s):  
Justin M. Deuerling ◽  
Weimin Yue ◽  
Alejandro A. Espinoza ◽  
Ryan K. Roeder
Keyword(s):  
Cortical Bone ◽  
Elastic Properties ◽  
Structural Information ◽  
Transversely Isotropic ◽  
Longitudinal Axis ◽  
Orientation Distribution ◽  
Tissue Properties ◽  
Apatite Crystals ◽  
Micromechanical Models ◽  
Anisotropic Elastic

The elastic constants of cortical bone are orthotropic or transversely isotropic depending on the anatomic origin of the tissue. Micromechanical models have been developed to predict anisotropic elastic properties from structural information. Many have utilized microstructural features such as osteons, cement lines and Haversian canals to model the tissue properties [1]. Others have utilized nanoscale features to model the mineralized collagen fibril [2]. Quantitative texture analysis using x-ray diffraction techniques has shown that elongated apatite crystals exhibit a preferred orientation in the longitudinal axis of the bone [3]. The orientation distribution of apatite crystals provides fundamental information influencing the anisotropy of the extracellular matrix (ECM) but has not been utilized in existing micromechanical models.

scholarly journals ESTIMATION OF ANISOTROPIC ELASTIC PROPERTIES OF CARBON FIBERS USING NANOINDENTATION

2020 ◽  
Vol 27 ◽  
pp. 107-111
Author(s):  
Thimmappa Shetty Guruprasad ◽  
Vincent Keryvin ◽  
Alain Bourmaud
Keyword(s):  
Elastic Properties ◽  
Carbon Fibers ◽  
Orientation Angle ◽  
Theoretical Models ◽  
Fiber Reinforced Polymers ◽  
Fiber Axis ◽  
Nanoindentation Test ◽  
Indentation Modulus ◽  
Carbon Fiber Reinforced Polymers ◽  
Anisotropic Elastic

Understanding the mechanical behavior of carbon fiber reinforced polymers requires knowledge on the deformation behavior of carbon fibers, they are highly anisotropic and heterogeneous. Nanoindentation is an efficient method for determining the mechanical properties in small volumes of materials. For isotropic materials, a single nanoindentation test can evaluate an elastic properties of the material. But for anisotropic material, the difficulty increases since measured indentation modulus depends on five elastic parameters (El,Et,Glt, νlt,and νtt) of the material. Nanoindentation experiments are performed on carbon fibers orientated between 0° to 90° at ten different orientations to the fiber axis. From theoretical models given by Vlassak et al. and Delafargue and Ulm, the elastic constants are predicted numerically by comparing the results of indentation modulus versus orientation angle with the experiments.

Modeling anisotropic static elastic properties of soft mudrocks with different clay fractions

Geophysics ◽  
2017 ◽  
Vol 82 (1) ◽  
pp. MR27-MR37 ◽  
Author(s):  
Biao Li ◽  
Ron C. K. Wong
Keyword(s):  
Elastic Properties ◽  
Void Ratio ◽  
Volume Fraction ◽  
Clay Fraction ◽  
Transversely Isotropic ◽  
Orientation Distribution ◽  
Simplified Approach ◽  
Effective Medium Approach ◽  
Anisotropic Elastic ◽  
Colorado Shale

We have quantified the effects of clay fraction and fabric on the static elastic properties of soft mudrocks with emphasis on microlevel mechanisms. Soft mudrocks are treated as a mixture of nonclay minerals and clay-water composites. We have devised a simplified approach to estimate the fabric orientation distribution of soft mudrocks based on measured parameters such as clay fraction and porosity. A single parameter (fabric angle) that characterizes the fabric orientation distribution of soft mudrocks is related to the void ratio of clay-water composites. The static transversely isotropic (TI) elastic properties of soft mudrocks are modeled using an anisotropic differential effective medium approach. The effect of variation in fabric orientation distribution on the TI elastic parameters of clay-water composites is studied by applying the Voigt approximation. With an increase of clay fraction, soft mudrocks have decreasing trends in the deformation moduli because some nonclay minerals are replaced by clay-water composites. However, the deformation moduli of clay-water composites could increase when there is more anisotropy in the fabric due to an increase in the clay fraction. Thus, the correlations between anisotropic elastic moduli and volume fraction of clay-water composites will display some fluctuations. Such nonlinear relationships are validated against published experimental data on Colorado shale samples from the Western Canadian Sedimentary Basin.

Free‐surface boundary conditions for elastic staggered‐grid modeling schemes

Geophysics ◽  
2002 ◽  
Vol 67 (5) ◽  
pp. 1616-1623 ◽  
Author(s):  
Rune Mittet
Keyword(s):  
Free Surface ◽  
Rayleigh Wave ◽  
Elastic Properties ◽  
Transversely Isotropic ◽  
Staggered Grid ◽  
Surface Boundary ◽  
Surface Boundary Conditions ◽  
Propagating Waves ◽  
Simple Implementation ◽  
Anisotropic Elastic

I present an accurate, stable, and simple implementation of the elastic free surface for staggered‐grid modeling schemes. The method is based on the presumption that the elastic Hooke's tensor on the free surface can be taken as similar to a transversely isotropic medium. The anisotropic elastic properties are then analyzed. The final scheme is isotropic, but with modified elastic properties on the free surface. The proposed scheme shows good agreement with an analytical solution. It is shown that the Rayleigh wave can not be properly resolved at two gridpoints per shortest wavelength if the shortest wavelength is calculated as the Rayleigh‐wave velocity over the maximum frequency. The Rayleigh wave is exponentially damped away from the free surface and requires denser sampling than purely propagating waves.

Nanoscale Elastic-Property Mapping with Contact-Resonance-Frequency AFM

2004 ◽  
Vol 838 ◽  
Author(s):  
D. C. Hurley ◽  
A. B. Kos ◽  
P. Rice
Keyword(s):  
Resonance Frequency ◽  
Elastic Properties ◽  
Digital Signal Processor ◽  
Contact Stiffness ◽  
Acoustic Microscopy ◽  
Indentation Modulus ◽  
Atomic Force ◽  
Resonance Frequencies ◽  
Vertical Contact ◽  
Contact Resonance

ABSTRACTWe describe a dynamic atomic force microscopy (AFM) method to map the nanoscale elastic properties of surfaces, thin films, and nanostructures. Our approach is based on atomic force acoustic microscopy (AFAM) techniques previously used for quantitative measurements of elastic properties at a fixed sample position. AFAM measurements determine the resonant frequencies of an AFM cantilever in contact mode to calculate the tip-sample contact stiffness k*. Local values for elastic properties such as the indentation modulus M can be determined from k* with the appropriate contact-mechanics models. To enable imaging at practical rates, we have developed a frequency-tracking circuit based on digital signal processor architecture to rapidly locate the contact-resonance frequencies at each image position. We present contact-resonance frequency images obtained using both flexural and torsional cantilever images as well as the corresponding vertical contact-stiffness (k*) image calculated from flexural frequency images. Methods to obtain elastic-modulus images of M from vertical contact-stiffness images are also discussed.

Anisotropic Elastic Properties of Low-k Dielectric Materials

2004 ◽  
Vol 812 ◽  
Author(s):  
A.A. Maznev ◽  
A. Mazurenko ◽  
G. Alper ◽  
C.J.L. Moore ◽  
M. Gostein ◽  
...  
Keyword(s):  
Elastic Properties ◽  
Acoustic Waves ◽  
Isotropic Material ◽  
Elastic Anisotropy ◽  
Surface Acoustic Waves ◽  
Transversely Isotropic ◽  
Dielectric Materials ◽  
Out Of Plane ◽  
Anisotropic Elastic ◽  
Low K

AbstractA non-contact optical technique based on laser-generated surface acoustic waves (SAWs) was used to characterize elastic properties of two types of thin (150-1100 nm) low-k films: more traditional non-porous organosilicate glass PECVD films (k=3.0) and novel mesoporous silica films fabricated in supercritical CO2 (k=2.2). The acoustic response of the non-porous samples is well described by a model of an elastically isotropic material with two elastic constants, Young's modulus and Poisson's ratio. Both parameters can be determined by analyzing SAW dispersion curves. However, the isotropic model fails to describe the SAW dispersion in the mesoporous samples. Modifying the model to allow a difference between in-plane and out-of plane properties (i.e., a transversely isotropic material) results in good agreement between the measurements and the model. The in-plane compressional modulus is found to be 2-3 times larger than the out-of plane modulus, possibly due to the anisotropic shape of the pores. Elastic anisotropy should therefore be taken into account in modeling mechanical behavior of low-k materials.

scholarly journals Effective elastic properties of transversely isotropic materials with concave pores

2021 ◽  
Vol 153 ◽  
pp. 103665
Author(s):  
K. Du ◽  
L. Cheng ◽  
J.F. Barthélémy ◽  
I. Sevostianov ◽  
A. Giraud ◽  
...  
Keyword(s):  
Elastic Properties ◽  
Transversely Isotropic ◽  
Effective Elastic Properties ◽  
Isotropic Materials ◽  
Transversely Isotropic Materials

scholarly journals Measurement of the Indentation Modulus and the Local Internal Friction in Amorphous SiO2 Using Atomic Force Acoustic Microscopy

2016 ◽  
Vol 61 (1) ◽  
pp. 9-12
Author(s):  
B. Zhang ◽  
H. Wagner ◽  
M. Büchsenschütz-Göbeler ◽  
Y. Luo ◽  
S. Küchemann ◽  
...  
Keyword(s):  
Internal Friction ◽  
Amorphous Materials ◽  
Contact Stiffness ◽  
Ultrasonic Transducer ◽  
Amorphous Material ◽  
Acoustic Microscopy ◽  
Damping Factor ◽  
Indentation Modulus ◽  
Amorphous Sio2 ◽  
Atomic Force

Abstract For the past two decades, atomic force acoustic microscopy (AFAM), an advanced scanning probe microscopy technique, has played a promising role in materials characterization with a good lateral resolution at micro/nano dimensions. AFAM is based on inducing out-of-plane vibrations in the specimen, which are generated by an ultrasonic transducer. The vibrations are sensed by the AFM cantilever when its tip is in contact with the material under test. From the cantilver’s contactresonance spectra, one determines the real and the imaginary part of the contact stiffness k*, and then from these two quantities the local indentation modulus M' and the local damping factor Qloc-1 can be obtained with a spatial resolution of less than 10 nm. Here, we present measured data of M' and of Qloc-1 for the insulating amorphous material, a-SiO2. The amorphous SiO2 layer was prepared on a crystalline Si wafer by means of thermal oxidation. There is a spatial distribution of the indentation modulus M' and of the internal friction Qloc-1. This is a consequence of the potential energy landscape for amorphous materials.

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