Self-affine Fracture Surface Parameters and Their Relationship with Microstructure in a Cast Aluminum Alloy

2002 ◽  
Vol 17 (6) ◽  
pp. 1276-1282 ◽  
Author(s):  
M. Hinojosa ◽  
J. Aldaco
Keyword(s):  
Aluminum Alloy ◽  
Fracture Surface ◽  
The Self ◽  
Cast Aluminum Alloy ◽  
Cast Aluminum ◽  
Force Microscopy ◽  
Fracture Surfaces ◽  
Atomic Force ◽  
Roughness Exponent

The possible role of microstructural features in determining the self-affinity of the fracture surface of a cast aluminum alloy is explored in this work. Fracture surfaces generated both in tension and impact tests were topometrically analyzed by atomic force microscopy, scanning electron microscopy, and stylus profilometry. The roughness exponent exhibited the “universal” value ζ ≈ 0.78, and the correlation length ζ was of the order of the grain size. The brittle intermetallic compounds known to be important in crack initiation did not show any correlation with the self-affine parameters of the resulting fracture surfaces in this particular case.

Self-Affine Quasi-Static Fracture of Soda-Lime Glass

2007 ◽  
Vol 560 ◽  
pp. 41-46 ◽  
Author(s):  
Claus Guerra-Amaro ◽  
M. Hinojosa ◽  
E. Reyes-Melo ◽  
V. González
Keyword(s):  
Soda Lime ◽  
The Self ◽  
Soda Lime Glass ◽  
Force Microscopy ◽  
Fracture Surfaces ◽  
Atomic Force ◽  
A Value ◽  
Roughness Exponent ◽  
Static Fracture ◽  
Static Conditions

In the present work we discuss the self-affine properties of the fracture surfaces of sodalime glass obtained under quasi-static conditions. The fracture surfaces are generated using a threepoint bending system in normal room conditions and under high humidity conditions. The surfaces were recorded both by Scanning Electron Microscopy and Atomic Force Microscopy, and their selfaffine properties are characterized using the Variable Bandwidth method. For both conditions it is observed that the major part of the fracture surface is occupied by the mirror zone. On the other hand, the self-affine analysis reveals that for both conditions the roughness exponent has values centred at around 0.58 with moderate dispersion, in agreement with previous results. Our findings support the hypothesis of the existence of a characteristic roughness exponent for quasi-static fracture with a value that is significantly lower than the value of 0.8 reported for rapid fracture conditions.

Microstructure and Self-Affine Fracture Surface Parameters in Steel

2006 ◽  
Vol 509 ◽  
pp. 43-48 ◽  
Author(s):  
J. Niño ◽  
M. Hinojosa ◽  
V. González
Keyword(s):  
Fracture Surface ◽  
Impact Test ◽  
Surface Parameters ◽  
Force Microscopy ◽  
Fracture Surfaces ◽  
Grain Sizes ◽  
Atomic Force ◽  
A Value ◽  
Roughness Exponent ◽  
Microstructural Condition

The fracture surfaces of SAE-1018 steel tension and impact test specimens with different grain sizes are analyzed in order to explore the possible relations between the microstructure and the self-affine fracture surface parameters such as the roughness exponent, ζ, and the correlation length, ξ. The topography of the fracture surfaces was observed and quantified by means of scanning electron microscopy, atomic force microscopy, optical microscopy and optical digitizer. It is confirmed that the fracture surfaces exhibit a self-affine behavior extending over six decades of length scale, from nanometers up to a few millimeters. The roughness exponent exhibits a value of ζ∼0.82 for all the cases regardless of the microstructural condition.

NANOSTRUCTURES FROM DESIGNER PEPTIDES

COSMOS ◽  
2008 ◽  
Vol 04 (02) ◽  
pp. 173-183
Author(s):  
BOON TEE ONG ◽  
PARAYIL KUMARAN AJIKUMAR ◽  
SURESH VALIYAVEETTIL
Keyword(s):  
Atomic Force Microscopy ◽  
Solid State ◽  
Self Assembly ◽  
Size Range ◽  
The Self ◽  
Mica Surface ◽  
Force Microscopy ◽  
Solution Structures ◽  
Atomic Force

The present article reviews the self-assembly of oligopeptides to form nanostructures, both in solution and in solid state. The solution structures of the peptides were examined using circular dichroism and dynamic light scattering. The solid state assembly was examined by adsorbing the peptides onto a mica surface and analyzing it using atomic force microscopy. The role of pH and salt concentration on the peptide self-assembly was also examined. Nanostructures within a size range of 3–10 nm were obtained under different conditions.

Morphology of Self-Assembled InAs Quantum Dots on GaAs(001)

2001 ◽  
Vol 696 ◽  
Author(s):  
F. Arciprete ◽  
F. Patella ◽  
M. Fanfoni ◽  
S. Nufris ◽  
E. Placidi ◽  
...  
Keyword(s):  
Nucleation And Growth ◽  
The Self ◽  
Two Dimensional ◽  
Wetting Layer ◽  
Inas Quantum Dots ◽  
Initial Formation ◽  
Force Microscopy ◽  
Atomic Force ◽  
Self Assembled

AbstractWe have followed by Atomic Force Microscopy (AFM) the epitaxial growth of InAs on GaAs(001) starting from the initial formation of a strained two-dimensional wetting layer up to the self-assembled nucleation and growth of 3D nanoparticles. In this work we underline many aspects of the morphology of this system, which substantiate the role either of kinetics on thermodynamics in the process of growth as well as the role of surface instabilities in controlling lateral ordering of the nanoaggregates.

Morphology of Self-Assembled InAs Quantum Dots on GaAs(001).

2001 ◽  
Vol 707 ◽  
Author(s):  
F. Arciprete ◽  
F. Patella ◽  
M. Fanfoni ◽  
S. Nufris ◽  
E. Placidi ◽  
...  
Keyword(s):  
Nucleation And Growth ◽  
The Self ◽  
Two Dimensional ◽  
Wetting Layer ◽  
Inas Quantum Dots ◽  
Initial Formation ◽  
Force Microscopy ◽  
Atomic Force ◽  
Self Assembled

ABSTRACTWe have followed by Atomic Force Microscopy (AFM) the epitaxial growth of InAs on GaAs(001) starting from the initial formation of a strained two-dimensional wetting layer up to the self-assembled nucleation and growth of 3D nanoparticles. In this work we underline many aspects of the morphology of this system, which substantiate the role either of kinetics on thermodynamics in the process of growth as well as the role of surface instabilities in controlling lateral ordering of the nanoaggregates.

Role of Alloy Matrix and Dispersoid on Corrosion Behavior of Cast Aluminum Alloy Composites

CORROSION ◽  
1998 ◽  
Vol 54 (2) ◽  
pp. 129-134 ◽  
Author(s):  
O. P. Modi ◽  
M. Saxena ◽  
B. K. Prasad ◽  
A. K. Jha ◽  
S. Das ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Corrosion Behavior ◽  
Cast Aluminum Alloy ◽  
Cast Aluminum ◽  
Alloy Matrix

Clathrin-Inspired Coating and Stabilization of Liposomes by DNA Self-Assembly

2019 ◽  
Author(s):  
Kevin N. Baumann ◽  
Luca Piantanida ◽  
Javier García-Nafría ◽  
Diana Sobota ◽  
Kislon Voïtchovsky ◽  
...  
Keyword(s):  
Self Assembly ◽  
Mechanical Stability ◽  
Lipid Vesicles ◽  
The Self ◽  
Force Microscopy ◽  
Atomic Force ◽  
Cryo Electron Microscopy ◽  
Further Development ◽  
Liposome Surface ◽  
Dna Coating

The self-assembly of the protein clathrin on biological membranes facilitates essential processes of endocytosis in biological systems and has provided a source of inspiration for materials design by the highly ordered structural appearance. By mimicking the architecture of clathrin self-assemblies to coat liposomes with biomaterials, new classes of hybrid carriers can be derived. Here we present a method for fabricating DNA-coated liposomes by hydrophobically anchoring and subsequently growing a DNA network on the liposome surface which structurally mimics clathrin assemblies. Dynamic light scattering (DLS), ζ-potential and cryo-electron microscopy (cryo-EM) measurements independently demonstrate successful DNA coating. Nanomechanical measurements conducted with atomic force microscopy (AFM) show that the DNA coating enhances the mechanical stability of the liposomes relative to uncoated ones. Furthermore, we provide the possibility to reverse the coating process by triggering the disassembly of the DNA coating through a toehold-mediated displacement reaction. Our results describe a straightforward, versatile, and reversible approach for coating and stabilizing lipid vesicles by an interlaced DNA network. This method has potential for further development towards the ordered arrangement of tailored functionalities on the surfaces of liposomes and for applications as hybrid nanocarrier.

THE PROCESS OF NANOMODIFYING CAST ALUMINUM ALLOY INGOTS FOR COMPONENTS OF AEROSPACE VEHICLES

2019 ◽  
Vol 20 (2) ◽  
pp. 268-276
Author(s):  
G. G. Krushenko ◽  
◽  
V. P. Nazarov ◽  
S. N. Reshetnikova ◽  
G. V. Dvirnyi ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Cast Aluminum Alloy ◽  
Cast Aluminum ◽  
Aerospace Vehicles
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