Characterization of mechanical properties of tungsten carbide/carbon multilayers: Cross-sectional electron microscopy and nanoindentation observations

2001 ◽  
Vol 16 (8) ◽  
pp. 2213-2222 ◽  
Author(s):  
N. J. M. Carvalho ◽  
J. Th. M. De Hosson
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Tungsten Carbide ◽  
Physical Vapor Deposition ◽  
Hysteresis Loops ◽  
Displacement Curve ◽  
Depth Sensing ◽  
Cross Sectional ◽  
Load Displacement ◽  
A New Technique

Multilayers of tungsten carbide/carbon (WC/C) deposited by physical vapor deposition onto steel substrates were subjected to depth-sensing indentation testing. The investigation aimed at probing the influence of dissimilarities between the microstructure of the multilayers and substrate on the system mechanical properties. The resultant load-displacement data were analyzed both by conventional load-displacement (P-δ) and load-displacement squared (P-δ2) plots. Furthermore, it was demonstrated that the occurrence of annular through-thickness cracks around the indentation sites can be identified from the load-displacement curve. Also, analysis of the lower part of the unloading curve permitted us to identify whether the coating had popped up by localized fracture. The cracking mechanism was characterized using a new technique for cross-sectional electron microscopy of the nanoindentations. The information retrieved with this technique eliminates the problems, inherent in assessing at this small contact scales, whether the fracture is by coating decohesion or by interfacial failure. In our case, it was demonstrated that the failure mechanism was decohesion of the carbon lamellae within the multilayers. The mechanical properties (hardness and effective Young's modulus) were also assessed by nanoindentation. The hysteresis loops were analyzed and discussed in terms of the method developed by Oliver and Pharr [J. Mater. Res. 7, 1564 (1992)].

Nano Indentations Studies of WC/C and TiN/(Ti,Al)N Multilayer PVD Coatings Combined with Cross-sectional Electron Microscopy Observations

2001 ◽  
Vol 697 ◽  
Author(s):  
N.J.M. Carvalho ◽  
J.Th.M. De Hosson
Keyword(s):  
Electron Microscopy ◽  
Physical Vapor Deposition ◽  
Amorphous Structure ◽  
Fracture Mechanisms ◽  
Accurate Information ◽  
Cross Sectional ◽  
Cracking Mechanisms ◽  
Load Displacement ◽  
A New Technique ◽  
Titanium Aluminum Nitride

AbstractMultilayers of tungsten carbide/carbon (WC/C) with an amorphous structure and multilayers of titanium nitride/titanium-aluminum nitride (TiN/(Ti,Al)N) with a polycrystalline structure, prepared by physical vapor deposition, have been subjected to nanoindentation testing. The investigation has been aimed at establishing whether the load-displacement responses provides accurate information on the fracture mechanisms and whether such mechanisms can be characterized using a new technique for cross-sectional electron microscopy of the nanoindentations. Analysis of the load-displacement curves showed that they can be used to identify the cracking mechanisms occurring in the multilayers and that cross-sectioning of the nanoindentations is necessary if a more complete understanding of the multilayer coatings behavior is required.

Cyclic Nanoindentation and Raman Microspectroscopy Study of Phase Transformations in Semiconductors

2000 ◽  
Vol 15 (4) ◽  
pp. 871-879 ◽  
Author(s):  
Yury G. Gogotsi ◽  
Vladislav Domnich ◽  
Sergey N. Dub ◽  
Andreas Kailer ◽  
Klaus G. Nickel
Keyword(s):  
Phase Transformation ◽  
Phase Transformations ◽  
Contact Pressure ◽  
Silicon Germanium ◽  
Hysteresis Loops ◽  
Metallic Phase ◽  
Raman Microspectroscopy ◽  
Displacement Curve ◽  
Depth Sensing ◽  
Load Displacement

This paper supplies new interpretation of nanoindentation data for silicon, germanium, and gallium arsenide based on Raman microanalysis of indentations. For the first time, Raman microspectroscopy analysis of semiconductors within nanoindentations is reported. The given analysis of the load-displacement curves shows that depth-sensing indentation can be used as a tool for identification of pressure-induced phase transformations. Volume change upon reverse phase transformation of metallic phases results either in a pop-out (or a kink-back) or in a slope change (elbow) of the unloading part of the load-displacement curve. Broad and asymmetric hysteresis loops of changing width, as well as changing slope of the elastic part of the loading curve in cyclic indentation can be used for confirmation of a phase transformation during indentation. Metallization pressure can be determined as average contact pressure (Meyer's hardness) for the yield point on the loading part of the load-displacement curve. The pressure of the reverse transformation of the metallic phase can be measured from pop-out or elbow on the unloading part of the diagram. For materials with phase transformations less pronounced than in Si, replotting of the loaddisplacement curves as average contact pressure versus relative indentation depth is required to determine the transformation pressures and/or improve the accuracy of data interpretation.

scholarly journals Novel Sulfonated Ethylene/1-Octene Copolymer Ionomer Nanocomposite: Synthesis and Properties

2013 ◽  
Vol 28 ◽  
pp. 59-66
Author(s):  
Sharmila Pradhan ◽  
Stefanie Scholtissek ◽  
Ralf Lach ◽  
Werner Lebek ◽  
Wolfgang Grellmann ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Layered Silicate ◽  
Chemical Society ◽  
Depth Sensing ◽  
Force Microscopy ◽  
Atomic Force ◽  
Solution Cast ◽  
Scanning Electron ◽  
Cast Technique

The nanocomposites based on sulfonated ethylene/1-octene copolymer (sEOC) and organophilic modified layered silicate were synthesized. The morphology of the ionomeric product was studied with the help of Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), Fourier Transform Infrared (FTIR) spectroscopy and microhardness measurements. It was shown that via the solution cast technique, the nanocomposite with uniformly distributed filer morphology can be conveniently prepared. The significant enhancement of the mechanical properties due to ionomerization was attested with the help of depth sensing microhardness measurements. It was found that the hardness of ionomer nanocomposite comprising 5 wt.-% layered silicate is approximately four fold of the neat elastomer. DOI: http://dx.doi.org/10.3126/jncs.v28i0.8060 Journal of Nepal Chemical Society Vol.28, 2011 Page : 59-66 Uploaded date: May 7, 2013

Surface Engineering of the Hydrogenated DLC (a-C:H) Coatings with Optimized Mechanical Performance

2013 ◽  
Vol 816-817 ◽  
pp. 33-37
Author(s):  
Mirela Contulov ◽  
Rodica Vladoiu ◽  
Aurelia Mandes ◽  
Victor Ciupina ◽  
Vilma Buršíková
Keyword(s):  
Mechanical Properties ◽  
Surface Engineering ◽  
Mechanical Performance ◽  
Vacuum Arc ◽  
Deposition Technique ◽  
Depth Sensing ◽  
Cross Sectional ◽  
Thermionic Vacuum Arc

The aim of this contribution is to present the properties of the hydrogenated DLC (a-C:H) films and to study their growth carried out in a special deposition technique based on Gaseous Thermionic Vacuum Arc (G-TVA) method. The mechanical properties were investigated on cross-sectional samples using the Fischerscope HM 2000 depth sensing indentation (DSI) tester.

X-ray Tomographic Characterization of Natural Polymer Composites and Correlation of Bulk Mechanical Properties

2009 ◽  
Vol 1219 ◽  
Author(s):  
Anahita Pakzad ◽  
Paul Mainwaring ◽  
Patricia A. Heiden ◽  
Reza Shahbazian Yassar
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Clear Correlation ◽  
Natural Polymer ◽  
Microscopy Imaging ◽  
X Ray ◽  
Nanomechanical Properties ◽  
The Matrix ◽  
A New Technique

AbstractIn this research, cellulose micro-crystals (CMC) were used to reinforce a bio-polymer, polycaprolactone (PCL). Mechanical properties were tested using nanoindentation. Electron microscopy imaging and a new technique called x-ray ultra microscopy and microtomography (XuM) were used to investigate the distribution of the filler in the matrix. We could demonstrate a clear correlation between the spatial distribution of CMC-PCL composites and their nanomechanical properties.

Contact damage evolution in diamondlike carbon coatings on ductile substrates

2008 ◽  
Vol 23 (1) ◽  
pp. 27-36 ◽  
Author(s):  
Rajnish K. Singh ◽  
M.T. Tilbrook ◽  
Z.H. Xie ◽  
A. Bendavid ◽  
P.J. Martin ◽  
...  
Keyword(s):  
Damage Evolution ◽  
Focused Ion Beam ◽  
Steel Substrate ◽  
Ion Beam ◽  
Chemical Vapor ◽  
Displacement Curve ◽  
Coating System ◽  
Cross Sectional ◽  
Diamondlike Carbon ◽  
Load Displacement

A diamondlike carbon (DLC) thin film was deposited onto a stainless steel substrate using a plasma-enhanced chemical vapor deposition (PECVD) process. Nanoindentation, coupled with focused-ion-beam (FIB) milling, was used to investigate contact-induced deformation and fracture in this coating system. Following initial elastic contact between the coating and the indenter and apparent plastic yield of the substrate, pop-ins were observed in the load–displacement curve, indicative of coating fracture. However, FIB cross-sectional images of indentations revealed the presence of ring, radial, and lateral cracks at loads much lower than the critical load for the first observed pop-ins. Finite element modeling was used, and the properties of the substrate and the film were calibrated by fitting the simulated load–displacement curves to experimental data. Then, based upon the experimental observations of damage evolution in this coating system, the stress distributions relevant to initiate ring, radial, and lateral cracks in the coating were ascertained. Furthermore, the effects of substrate yield stress and coating residual stress on the formation of these cracks were investigated.

Fabrication of Planar and Cross-Sectional TEM Specimens Using a Focused Ion Beam

1990 ◽  
Vol 199 ◽  
Author(s):  
R. J. Young ◽  
E. C. G. Kirk ◽  
D. A. Williams ◽  
H. Ahmed
Keyword(s):  
Electron Microscopy ◽  
Integrated Circuits ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Cross Sectional ◽  
Transmission Electron ◽  
A New Technique ◽  
Sectional Analysis ◽  
Selection Of ◽  
Better Than

ABSTRACTA new technique using a focused ion beam has been developed for the fabrication of transmission electron microscopy specimens in pre-selected regions. The method has been proven in the fabrication of both cross-sectional and planar specimens, with no induced artefacts. The lateral accuracy achievable in the selection of an area for cross-sectional analysis is better than one micrometre. The technique has been applied to a number of silicon and III-V based integrated circuits, and is expected to be suitable for many other materials and structures.

The Deformation Mechanism at Pop-In: Monocrystalline Silicon under Nanoindentation with a Berkovich Indenter

2008 ◽  
Vol 389-390 ◽  
pp. 453-458 ◽  
Author(s):  
Li Chang ◽  
Liang Chi Zhang
Keyword(s):  
Mechanical Properties ◽  
Phase Transition ◽  
Loading Rate ◽  
Monocrystalline Silicon ◽  
Displacement Curve ◽  
Berkovich Indenter ◽  
Rapid Loading ◽  
Slope Change ◽  
Indentation Tests ◽  
Load Displacement

This paper investigates the “pop-in” behavior of monocrystalline silicon under nanoindentation with a Berkovich indenter. The indentation tests were carried out under ultra-low loads, i.e. 100 μN and 300 μN, with different loading/unloading rates. It was found that with the experimentally determined area function of the indenter tip, the mechanical properties of silicon can be accurately calculated from the load-displacement data, that a pop-in event represents the onset of phase transition, and that a lower loading rate favours a sudden volume change but a rapid loading process tends to generate a gradual slope change of the load-displacement curve.

scholarly journals Analysis on the Mechanical Performance of the Joints of the Wheel-coupler type formwork Support

2021 ◽  
Vol 261 ◽  
pp. 02070
Author(s):  
Shilong Jia ◽  
Fang Zhou ◽  
Zhongliang Chen
Keyword(s):  
Mechanical Properties ◽  
Bearing Capacity ◽  
Mechanical Performance ◽  
Ultimate Bearing Capacity ◽  
Displacement Curve ◽  
Ansys Software ◽  
Rotational Stiffness ◽  
Non Linear ◽  
Tension And Compression ◽  
Load Displacement

In order to study the mechanical properties of the joints, ANSYS software was used to simulate and analyse the failure form, ultimate bearing capacity, load-displacement curve and the rotational stiffness of the wheel-coupler joint node under force. Results: The wheel-coupler joint node has obvious non-linear characteristics when subjected to force; The bilateral symmetric tension and compression state could better reflect the failure form and deformation of the joint; The rotational stiffness of the wheel-coupler joint node under tension and bending was greater than that under bending and torsion, and was greater than that under tension, bending and torsion.

Sign in / Sign up

Export Citation Format

Share Document