scholarly journals Evaluation of fracture toughness of small volumes by means of cube-corner nanoindentation

2012 ◽  
Vol 66 (9) ◽  
pp. 670-673 ◽  
Author(s):  
N. Cuadrado ◽  
D. Casellas ◽  
M. Anglada ◽  
E. Jiménez-Piqué
Keyword(s):  
Fracture Toughness ◽  
Cube Corner

Characterizing Anisotropic Fracture Toughness of Shale Using Nanoindentation

2021 ◽  
pp. 1-13
Author(s):  
Erica Esatyana ◽  
Mehdi Alipour ◽  
A. Sakhaee-Pour
Keyword(s):  
Fracture Toughness ◽  
Conceptual Model ◽  
Effective Medium Theory ◽  
Fused Silica ◽  
Small Samples ◽  
Medium Theory ◽  
Anisotropic Fracture ◽  
Cube Corner ◽  
Induced Fractures ◽  
Anisotropic Fracture Toughness

Summary Shale, which has pores as small as 10 nm, is economically viable for hydrocarbon recovery when it is fractured. Although the fracture toughness dictates the required energy for the improvement, the existing techniques are not suitable for characterization at scales smaller than 1 cm. Developing practical methods for characterization is crucial because fractures can contribute to an accessible pore volume at different scales. This study proposes a conceptual model to characterize the anisotropic fracture toughness of shale using nanoindentations on a sub-1-cm scale. The conceptual model reveals the complexities of characterizing shales and explains why induced fractures differ from those observed in more-homogeneous media, such as fused silica. Samples from the Wolfcamp Formation were tested using Berkovich and cube-corner tips, and the interpreted fracture toughness values are promising. The conceptual model is the first application of the effective-medium theory for fracture toughness characterization using nanoindentation. In addition, it can quantify fracture toughness variations when using small samples, such as drill cuttings.

scholarly journals Cracking During Nanoindentation and its Use in the Measurement of Fracture Toughness

1994 ◽  
Vol 356 ◽  
Author(s):  
D. S. Harding ◽  
W. C. Oliver ◽  
G. M. Pharr
Keyword(s):  
Thin Film ◽  
Fracture Toughness ◽  
Small Volume ◽  
Brittle Materials ◽  
Empirical Method ◽  
Berkovich Indenter ◽  
Empirical Constant ◽  
Cube Corner ◽  
Semi Empirical ◽  
Radial Cracks

AbstractResults of an investigation aimed at developing a technique by which the fracture toughness of a thin film or small volume can be determined in nanoindentation experiments are reported. The method is based on the radial cracking which occurs when brittle materials are deformed by a sharp indenter such as a Vickers or Berkovich diamond. In microindentation experiments, the lengths of radial cracks have been found to correlate reasonably well with fracture toughness, and a simple semi-empirical method has been developed to compute the toughness from the crack lengths. However, a problem is encountered in extending this method into the nanoindentation regime with the standard Berkovich indenter in that there are well defined loads, called cracking thresholds, below which indentation cracking does not occur in most brittle materials. We have recently found that the problems imposed by the cracking threshold can be largely overcome by using an indenter with the geometry of the corner of a cube. For the cube-corner indenter, cracking thresholds in most brittle materials are as small as 1 mN (∼ 0.1 grams). In addition, the simple, well-developed relationship between toughness and crack length used for the Vickers indenter in the microindentation regime can be used for the cube-corner indenter in the nanoindentation regime provided a different empirical constant is used.

Sharp probes of varying acuity: Instrumented indentation and fracture behavior

2004 ◽  
Vol 19 (1) ◽  
pp. 165-175 ◽  
Author(s):  
Dylan J. Morris ◽  
Sasha B. Myers ◽  
Robert F. Cook
Keyword(s):  
Fracture Toughness ◽  
Fracture Behavior ◽  
Instrumented Indentation ◽  
Cube Corner ◽  
Load Displacement ◽  
Estimation Models

The fracture and instrumented indentation behavior of a range of materials subjected to indentation by four sharp probes varying in acuity from the Berkovich to the cube-corner was studied. Quantities derived from load, displacement, and continuous stiffness measurements were evaluated for their ability to detect “pop-in”—sudden displacement excursions associated with fracture. It was found that gross unloading character was sensitive to the presence of fracture, even when no pop-in was detected. This may be useful in the development of fracture toughness estimation models that do not rely on the imaging of cracks.

scholarly journals Nanoindentation of Silicate Low-K Dielectric Thin Films

2002 ◽  
Vol 716 ◽  
Author(s):  
Joseph B. Vella ◽  
Alex A. Volinsky ◽  
Indira S. Adhihetty ◽  
N.V. Edwards ◽  
William W. Gerberich
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
Dielectric Constant ◽  
Elastic Modulus ◽  
Percolation Theory ◽  
Scratch Testing ◽  
Dielectric Thin Films ◽  
Cube Corner ◽  
Low K

AbstractThe capabilities of nanoindentation to characterize low-k organo silicate glass (OSG) thin films is explored as a relatively rapid and inexpensive metric of mechanical properties, adhesion strength, and fracture toughness. One method of decreasing the static dielectric constant of OSG interlayer dielectrics requires the introduction of porosity in the material which has a dramatic impact on its mechanical and toughness properties. Percolation theory is used to formulate a correlation between porosity and elastic modulus. Using cube corner diamond indentation and scratch testing fracture toughness calculations are also discussed.

scholarly journals Fracture toughness determination of fused silica by cube corner indentation cracking and pillar splitting

2020 ◽  
Vol 186 ◽  
pp. 108311 ◽  
Author(s):  
Sebastian Bruns ◽  
Laszlo Petho ◽  
Christian Minnert ◽  
Johann Michler ◽  
Karsten Durst
Keyword(s):  
Fracture Toughness ◽  
Fused Silica ◽  
Cube Corner

Methodology to Determine the Toughness of a Brittle Thin Film by Nanoindentation

2006 ◽  
Vol 914 ◽  
Author(s):  
Helene Brillet-Rouxel ◽  
Marc Verdier ◽  
Michel Dupeux ◽  
Muriel Braccini ◽  
Stéphane Orain
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Fracture Toughness ◽  
Bulk Silicon ◽  
Si Substrate ◽  
Dielectric Thin Films ◽  
Estimation Formula ◽  
Cube Corner ◽  
Local Technique ◽  
Film Substrate

AbstractNanoindentation is the most convenient local technique for measuring elastic modulus, hardness, and fracture toughness of dielectric thin films. This approach is applied to bulk silicon and dielectric thin films (porous and non-porous) on silicon substrate. Reproducible stable cracks are generated from the edges of a cube corner indentor. The validity of theoretical model of use to estimate the toughness from cracks length has been checked on these reference cases. To calculate the toughness of thin film on Si substrate, we first established the loading range in which the cracks only affect the thin film without substrate damage. Several corrective terms have been introduced to the classical toughness estimation formula to take into account the proximity of the film/substrate interface and the residual stress pre-existing in the film. This approach is discussed by comparing experimental results obtained including these improvements to literature results.

Indentation Fracture Toughness Measurements of Low Dielectric Constant Materials

2003 ◽  
Vol 766 ◽  
Author(s):  
Dylan J. Morris ◽  
Robert F. Cook
Keyword(s):  
Fracture Toughness ◽  
Film Thickness ◽  
Scaling Laws ◽  
Film Stress ◽  
Low Dielectric ◽  
Fracture Toughness Measurement ◽  
Cube Corner ◽  
Simple Scaling ◽  
Low Dielectric Constant Materials ◽  
Low K

AbstractThe physics and mechanics of a fracture toughness measurement technique for low-k films are described. It has been observed experimentally that it is possible to generate reproducible stable cracks at indentation sites in thin low-k films using cube-corner indentation. The fracture response depends on the film thickness and follows no simple scaling laws. The physics of a model that takes into account the stress fields from indentation and film stress, with particular attention paid to the Poisson's ratio of the film, are described. The model is able to predict the changes in observables when the film thickness is changed, which allows one to estimate film toughness independent of the configuration of the material.

scholarly journals A method to determine fracture toughness using cube-corner indentation

2010 ◽  
Vol 62 (4) ◽  
pp. 199-201 ◽  
Author(s):  
Taihua Zhang ◽  
Yihui Feng ◽  
Rong Yang ◽  
Peng Jiang
Keyword(s):  
Fracture Toughness ◽  
Cube Corner ◽  
Determine Fracture Toughness

Precipitation in Al-Li-Zr alloys

1992 ◽  
Vol 50 (1) ◽  
pp. 186-187
Author(s):  
D.M. Vanderwalker
Keyword(s):  
Fracture Toughness ◽  
Precipitation Hardening ◽  
Weight Ratio ◽  
High Strength ◽  
Transmission Electron ◽  
Water Quench ◽  
Aluminum Lithium ◽  
Aluminum Lithium Alloys ◽  
Lithium Alloys ◽  
Zr Alloys

Aluminum-lithium alloys have a low density and high strength to weight ratio. They are being developed for the aerospace industry.The high strength of Al-Li can be attributed to precipitation hardening. Unfortunately when aged, Al-Li aquires a low ductility and fracture toughness. The precipitate in Al-Li is part of a sequence SSSS → Al3Li → AlLi A description of the phases may be found in reference 1 . This paper is primarily concerned with the Al3Li phase. The addition of Zr to Al-Li is being explored to find the optimum in properties. Zirconium improves fracture toughness and inhibits recrystallization. This study is a comparision between two Al-Li-Zr alloys differing in Zr concentration.Al-2.99Li-0.17Zr(alloy A) and Al-2.99Li-0.67Zr (alloy B) were solutionized for one hour at 500oc followed by a water quench. The specimens were then aged at 150°C for 16 or 40 hours. The foils were punched into 3mm discs. The specimens were electropolished with a 1/3 nitric acid 2/3 methanol solution. The transmission electron microscopy was conducted on the JEM 200CX microscope.

Microstructural and fractographic characterization of B4C-Al cermets tested under dynamic and static loading

1989 ◽  
Vol 47 ◽  
pp. 562-563
Author(s):  
Gyeung Ho Kim ◽  
Mehmet Sarikaya ◽  
D. L. Milius ◽  
I. A. Aksay
Keyword(s):  
Thin Film ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
Static Loading ◽  
Carbon Deposition ◽  
Full Density ◽  
Unique Combination ◽  
Strong Component ◽  
Reaction Products

Cermets are designed to optimize the mechanical properties of ceramics (hard and strong component) and metals (ductile and tough component) into one system. However, the processing of such systems is a problem in obtaining fully dense composite without deleterious reaction products. In the lightweight (2.65 g/cc) B4C-Al cermet, many of the processing problems have been circumvented. It is now possible to process fully dense B4C-Al cermet with tailored microstructures and achieve unique combination of mechanical properties (fracture strength of over 600 MPa and fracture toughness of 12 MPa-m1/2). In this paper, microstructure and fractography of B4C-Al cermets, tested under dynamic and static loading conditions, are described.The cermet is prepared by infiltration of Al at 1150°C into partially sintered B4C compact under vacuum to full density. Fracture surface replicas were prepared by using cellulose acetate and thin-film carbon deposition. Samples were observed with a Philips 3000 at 100 kV.

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