The Nanomechanics of Tetrahedral Amorphous Diamond-Like Carbon (ta-C) MEMS

2003 ◽  
Author(s):  
I. Chasiotis ◽  
S. W. Cho ◽  
T. A. Friedmann ◽  
J. P. Sullivan
Keyword(s):  
Strain Analysis ◽  
Film Surface ◽  
Image Correlation ◽  
Diamond Like Carbon ◽  
Tensile Stresses ◽  
Notched Specimens ◽  
Failure Properties ◽  
First Time ◽  
Very High

The mechanics of hydrogen-free tetrahedral amorphous diamond-like carbon (ta-C) MEMS structures have been investigated in connection with their elastic and failure properties. For this purpose, micro-tension specimens of thicknesses between 1.2 μm and 1.8 μm and gage widths of 10 μm or 50 μm have been fabricated by the Sandia National Laboratories (SNL). The mechanical characterization has been conducted via in situ AFM measurements and Digital Image Correlation (DIC) data strain analysis and the deformation fields of uniform tension specimens and internally notched specimens with acute notches (K=27) have been experimentally obtained. The elastic modulus and Poisson’s ratio were measured for the first time directly from the specimens averaging 750 GPa and ν=0.16 respectively, while the tensile strength was found to be very consistent averaging 7.0 GPa. Stressed material domains with smaller dimensions in the vicinity of micronotches exhibited even higher failure strength reaching an average of 11.5 GPa with about 10% scatter. AFM images of specimens under high tensile stresses have also indicated the possibility of an sp3 to sp2 phase transformation on the film surface at very high tensile stresses (>6 GPa).

Young's Modulus, Poisson's Ratio, and Nanoscale Deformation Fields of MEMS Materials

2003 ◽  
Vol 795 ◽  
Author(s):  
I. Chasiotis ◽  
S. W. Cho ◽  
T. A. Friedmann ◽  
J. P. Sullivan
Keyword(s):  
Phase Transformations ◽  
Young’S Modulus ◽  
Poisson’S Ratio ◽  
Young's Modulus ◽  
Film Surface ◽  
Local Deformation ◽  
Image Correlation ◽  
Poisson's Ratio ◽  
First Time

ABSTRACTThe mechanical properties of hydrogen-free tetrahedral amorphous diamond-like carbon have been investigated in connection with its elastic and failure properties. Micro-tension specimens of gage thickness of 1.2–1.8 μm and widths of 10 μm or 50 μm have been fabricated by the Sandia National Laboratories (SNL). The mechanical characterization has been conducted via in situ AFM measurements and Digital Image Correlation (DIC) data strain analysis and the local deformation fields of (a) uniform and (b) internally notched tension specimens with acute notches (K=27) have been experimentally obtained. Young's modulus and Poisson's ratio were measured for the first time directly from such small specimens and averaged 750 GPa and v=0.16 respectively, while the tensile strength was found to be very consistent averaging 7.1 GPa. Stressed material domains with smaller dimensions in the vicinity of micronotches exhibited even higher failure strengths reaching 11.5 GPa with limited data scatter. AFM images of in situ tested specimens have indicated sp3 to sp2 phase transformations on the film surface that was subject to ultra-high tensile stresses (>6 GPa). This is the first time these phase transformations are observed during tensile tests of brittle materials.

scholarly journals Strain Analysis on Electrochemical Failures of Nanoscale Silicon Electrode Based on Three-Dimensional In Situ Measurement

2020 ◽  
Vol 10 (2) ◽  
pp. 468 ◽  
Author(s):  
Zhifeng Qi ◽  
Zhongqiang Shan ◽  
Weihao Ma ◽  
Linan Li ◽  
Shibin Wang ◽  
...  
Keyword(s):  
Silicon Film ◽  
Three Dimensional ◽  
Strain Analysis ◽  
Image Correlation ◽  
Mechanical Parameters ◽  
Stress Strain ◽  
Full Field ◽  
Battery Capacity

Nanoscale silicon film electrodes in Li-ion battery undergo great deformations leading to electrochemical and mechanical failures during repeated charging-discharging cycles. In-situ experimental characterization of the stress/strain in those electrodes still faces big challenges due to remarkable complexity of stress/strain evolution while it is still hard to predict the association between the electrode cycle life and the measurable mechanical parameters. To quantificationally investigate the evolution of the mechanical parameters, we develop a new full field 3D measurement method combining digital image correlation with laser confocal profilometry and propose a strain criterion of the failure based on semi-quantitative analysis via mean strain gradient (MSG). The experimental protocol and results illustrate that the revolution of MSG correlates positively with battery capacity decay, which may inspire future studies in the field of film electrodes.

Development of a photomicroscope method for in situ damage monitoring under ultrasonic fatigue test

2022 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Kai Tan ◽  
Victor Postel ◽  
Yujia Liu ◽  
Dongtong Yang ◽  
Sen Tang ◽  
...  
Keyword(s):  
Crack Propagation ◽  
Early Stage ◽  
Strain Analysis ◽  
Infrared Camera ◽  
Small Crack ◽  
Image Correlation ◽  
Content Type ◽  
Damage Monitoring ◽  
Ultrasonic Fatigue

PurposeMechanical issues related to the information and growth of small cracks are considered to play a major role in very high cycle fatigue (VHCF) for metallic materials. Further efforts on better understanding in early stage of a crack are beneficial to estimating and preventing catastrophic damage for a long period service.Design/methodology/approachDependent on the ultrasonic loading system, a novel method of in situ photomicroscope is established to study the crack behaviors in VHCF regime.FindingsThis in situ photomicroscope method provides advantages in combination with fatigue damage monitoring at high magnification, a large number of cycles, and efficiency. Visional investigation with attached image proceeding code proves that the method has high resolution on both size and time, which permits reliable accuracy on small crack growth rate. It is observed that the crack propagation trends slower in the overall small crack stage down to the level of 10–11 m/cycle. Strain analysis relays on a real-time recording which is applied by using digital image correlation. Infrared camera recording indicates the method is also suitable for thermodynamic study while growth of damage.Originality/valueBenefiting from this method, it is more convenient and efficient to study the short crack propagation in VHCF regime.

Strain Analysis of Multi-Phase Steel Using In-Situ EBSD Tensile Testing and Digital Image Correlation

2021 ◽  
Author(s):  
Kyung Il Kim ◽  
Yeonju Oh ◽  
Dong Uk Kim ◽  
Joo-Hee Kang ◽  
Nam Ik Cho ◽  
...  
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Tensile Testing ◽  
Strain Analysis ◽  
Image Correlation ◽  
Multi Phase

Calcium-aluminum-silicate-hydrate “cement” phases and rare Ca-zeolite association at Colle Fabbri, Central Italy

2010 ◽  
Vol 2 (2) ◽  
Author(s):  
F. Stoppa ◽  
F. Scordari ◽  
E. Mesto ◽  
V. Sharygin ◽  
G. Bortolozzi
Keyword(s):  
Central Italy ◽  
Aluminum Silicate ◽  
Hydrothermal Conditions ◽  
High Calcium ◽  
Hydrate Cement ◽  
Natural Analogues ◽  
First Time ◽  
Cement Clinkers ◽  
Very High

AbstractVery high temperature, Ca-rich alkaline magma intruded an argillite formation at Colle Fabbri, Central Italy, producing cordierite-tridymite metamorphism in the country rocks. An intense Ba-rich sulphate-carbonate-alkaline hydrothermal plume produced a zone of mineralization several meters thick around the igneous body. Reaction of hydrothermal fluids with country rocks formed calcium-silicate-hydrate (CSH), i.e., tobermorite-afwillite-jennite; calcium-aluminum-silicate-hydrate (CASH) — “cement” phases - i.e., thaumasite, strätlingite and an ettringite-like phase and several different species of zeolites: chabazite-Ca, willhendersonite, gismon-dine, three phases bearing Ca with the same or perhaps lower symmetry of phillipsite-Ca, levyne-Ca and the Ca-rich analogue of merlinoite. In addition, apophyllite-(KF) and/or apophyllite-(KOH), Ca−Ba-carbonates, portlandite and sulphates were present. A new polymorph from the pyrrhotite group, containing three layers of sphalerite-type structure in the unit cell, is reported for the first time. Such a complex association is unique. Most of these minerals are specifically related to hydration processes of: (1) pyrometamorphic metacarbonate/metapelitic rocks (natural analogues of cement clinkers); (2) mineralization between intrusive stocks and slates; and (3) high-calcium, alkaline igneous rocks such as melilitites and foidites as well as carbonatites. The Colle Fabbri outcrop offers an opportunity to study in situ complex crystalline overgrowth and specific crystal chemistry in mineral phases formed in igneous to hydrothermal conditions.

NOVEL VACUUM SYSTEM FOR IN-SITU CHARACTERIZATION OF FLUORESCENCE PROPERTIES OF THIN FILMS

2002 ◽  
Vol 16 (28n29) ◽  
pp. 4445-4448 ◽  
Author(s):  
KOHEI ONOZUKA ◽  
NOBUYUKI IWATA ◽  
HIROSHI YAMAMOTO
Keyword(s):  
Thin Films ◽  
Thermal Evaporation ◽  
Film Surface ◽  
Fluorescence Properties ◽  
Luminescence Properties ◽  
Vacuum System ◽  
In Situ Characterization ◽  
First Time

We constructed a novel vacuum system in which the cathode luminescence properties of as-prepared films can be measured in-situ. It has been observed that the Zn-Ga-O films deposited on 500°C ITO by sputtering emits light with wavelength of about 500 nm from an ultra thin Zn-rich layer formed near film surface. The luminescence induced by irradiation of electrons has also been observed for the first time in the organic bilayered TPD/Alq 3 films prepared in thermal evaporation. Its wavelength blue-shifts by about 120 nm in comparison with the electroluminescence of the same materials. The developed vacuum system is useful to characterize various thin films.

scholarly journals In Situ Probing Potassium-ion Intercalation-induced Amorphization in Crystalline Iron Phosphate Cathode Materials

2021 ◽  
Author(s):  
bertan ozdogru ◽  
Younghwan Cha ◽  
Vijay Murugesan ◽  
Min-Kyu Song ◽  
ozgur capraz
Keyword(s):  
Large Scale ◽  
Strain Analysis ◽  
Iron Phosphate ◽  
Image Correlation ◽  
Electrode Structure ◽  
Dynamic Changes ◽  
In Operando ◽  
Xrd Techniques ◽  
Ion Intercalation

<p>Na-ion and K-ion batteries are promising alternatives for large-scale energy storage applications due to their abundancy and lower cost. However, designing an electrode structure to reversibly accommodate these large alkali-ions is the remaining challenge before their commercialization. Intercalation of these large ions could cause irreversible structural deformations and amorphization in the crystalline electrodes. The designing of new amorphous electrodes is another route to develop electrodes to store these ions reversibly. Lack of understanding of dynamic changes in the amorphous nanostructures during battery operation is the bottleneck for further developments. Here, we report the utilization of in situ digital image correlation and in-operando X-ray diffraction (XRD) techniques to probe dynamic changes in the amorphous phase of iron phosphate during potassium intercalation. In-operando XRD demonstrates amorphization in the electrode’s nanostructure during the first charge / discharge cycle. In situ strain analysis detects the reversible deformations associated with redox reactions in the amorphous phases. This method offers new insights to study mechanics of ion intercalation in the amorphous nanostructures.</p>

scholarly journals In Situ Probing Potassium-ion Intercalation-induced Amorphization in Crystalline Iron Phosphate Cathode Materials

2021 ◽  
Author(s):  
bertan ozdogru ◽  
Younghwan Cha ◽  
Vijay Murugesan ◽  
Min-Kyu Song ◽  
ozgur capraz
Keyword(s):  
Large Scale ◽  
Strain Analysis ◽  
Iron Phosphate ◽  
Image Correlation ◽  
Electrode Structure ◽  
Dynamic Changes ◽  
In Operando ◽  
Xrd Techniques ◽  
Ion Intercalation

<p>Na-ion and K-ion batteries are promising alternatives for large-scale energy storage applications due to their abundancy and lower cost. However, designing an electrode structure to reversibly accommodate these large alkali-ions is the remaining challenge before their commercialization. Intercalation of these large ions could cause irreversible structural deformations and amorphization in the crystalline electrodes. The designing of new amorphous electrodes is another route to develop electrodes to store these ions reversibly. Lack of understanding of dynamic changes in the amorphous nanostructures during battery operation is the bottleneck for further developments. Here, we report the utilization of in situ digital image correlation and in-operando X-ray diffraction (XRD) techniques to probe dynamic changes in the amorphous phase of iron phosphate during potassium intercalation. In-operando XRD demonstrates amorphization in the electrode’s nanostructure during the first charge / discharge cycle. In situ strain analysis detects the reversible deformations associated with redox reactions in the amorphous phases. This method offers new insights to study mechanics of ion intercalation in the amorphous nanostructures.</p>

Epitaxial growth manner and structure of superconducting oxide films

1990 ◽  
Vol 48 (4) ◽  
pp. 2-3
Author(s):  
Yoshichika Bando ◽  
Takahito Terashima ◽  
Kenji Iijima ◽  
Kazunuki Yamamoto ◽  
Kazuto Hirata ◽  
...  
Keyword(s):  
Ultrathin Films ◽  
Film Surface ◽  
High Energy ◽  
Epitaxial Films ◽  
Layer By Layer ◽  
Initial Growth ◽  
In Situ Growth ◽  
High Quality ◽  
Activated Reactive Evaporation

The high quality thin films of high-Tc superconducting oxide are necessary for elucidating the superconducting mechanism and for device application. The recent trend in the preparation of high-Tc films has been toward “in-situ” growth of the superconducting phase at relatively low temperatures. The purpose of “in-situ” growth is to attain surface smoothness suitable for fabricating film devices but also to obtain high quality film. We present the investigation on the initial growth manner of YBCO by in-situ reflective high energy electron diffraction (RHEED) technique and on the structural and superconducting properties of the resulting ultrathin films below 100Å. The epitaxial films have been grown on (100) plane of MgO and SrTiO, heated below 650°C by activated reactive evaporation. The in-situ RHEED observation and the intensity measurement was carried out during deposition of YBCO on the substrate at 650°C. The deposition rate was 0.8Å/s. Fig. 1 shows the RHEED patterns at every stage of deposition of YBCO on MgO(100). All the patterns exhibit the sharp streaks, indicating that the film surface is atomically smooth and the growth manner is layer-by-layer.

Probing the Dynamic Self-Assembly Behaviour of Photoswitchable Wormlike Micelles in Real Time

2018 ◽  
Author(s):  
Elaine A. Kelly ◽  
Judith E. Houston ◽  
Rachel Evans
Keyword(s):  
Real Time ◽  
Absorption Spectroscopy ◽  
Self Assembly ◽  
Uv Light ◽  
Wormlike Micelles ◽  
Tetraethylene Glycol ◽  
Light Illumination ◽  
First Time ◽  
Dependent Processes

Understanding the dynamic self-assembly behaviour of azobenzene photosurfactants (AzoPS) is crucial to advance their use in controlled release applications such as<i></i>drug delivery and micellar catalysis. Currently, their behaviour in the equilibrium <i>cis-</i>and <i>trans</i>-photostationary states is more widely understood than during the photoisomerisation process itself. Here, we investigate the time-dependent self-assembly of the different photoisomers of a model neutral AzoPS, <a>tetraethylene glycol mono(4′,4-octyloxy,octyl-azobenzene) </a>(C<sub>8</sub>AzoOC<sub>8</sub>E<sub>4</sub>) using small-angle neutron scattering (SANS). We show that the incorporation of <i>in-situ</i>UV-Vis absorption spectroscopy with SANS allows the scattering profile, and hence micelle shape, to be correlated with the extent of photoisomerisation in real-time. It was observed that C<sub>8</sub>AzoOC<sub>8</sub>E<sub>4</sub>could switch between wormlike micelles (<i>trans</i>native state) and fractal aggregates (under UV light), with changes in the self-assembled structure arising concurrently with changes in the absorption spectrum. Wormlike micelles could be recovered within 60 seconds of blue light illumination. To the best of our knowledge, this is the first time the degree of AzoPS photoisomerisation has been tracked <i>in</i><i>-situ</i>through combined UV-Vis absorption spectroscopy-SANS measurements. This technique could be widely used to gain mechanistic and kinetic insights into light-dependent processes that are reliant on self-assembly.

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