scholarly journals A Note on Residual Stress, Lattice Orientation and Dislocation Density in Crystalline Solids

2012 ◽  
Vol 109 (2) ◽  
pp. 275-283 ◽  
Author(s):  
David J. Steigmann ◽  
Ray W. Ogden
Keyword(s):  
Residual Stress ◽  
Dislocation Density ◽  
Crystalline Solids ◽  
Lattice Orientation ◽  
Stress Lattice

The Influence of Substrate Patterning on Threading Dislocation Density and Residual Stress in GaAs/Si Heteroepitaxial Layers.

1990 ◽  
Vol 198 ◽  
Author(s):  
Hyunchul Sohn ◽  
Eicke R. Weber ◽  
Jay Tu ◽  
Henry P. Lee ◽  
Shy Wang
Keyword(s):  
Residual Stress ◽  
Dislocation Density ◽  
Threading Dislocation ◽  
Etch Pits ◽  
Cross Sectional ◽  
Strained Layers ◽  
Si Substrates ◽  
Growth Area ◽  
Threading Dislocation Density ◽  
Influence Of Substrate

ABSTRACTThe growth of GaAs films by MBE on mesa-type patterned Si substrates has been investigated. Mesa widths were varied from 10 µm to 200 µm and were prepared using chemical etching with Si3N4 masks and reactive ion etching. The residual stress in the epitaxial layer was estimated using low temperature (7K) photoluminescence and the defect distribution was studied by cross sectional TEM, dislocation densities were in addition determined by etch pits. The residual stress and the dislocation density decreased monotonically with the reduction of growth area. By the incorporation of strained layers with the reduction of growth area, the etch pit density in GaAs layers on mesas was reduced further.

Effect of Optimization of Shot Peening Parameters on Surface Integrity of NAK80

2010 ◽  
Vol 426-427 ◽  
pp. 537-539 ◽  
Author(s):  
Hong Miao ◽  
Dun Wen Zuo ◽  
Hong Feng Wang ◽  
X.W. Sha
Keyword(s):  
Residual Stress ◽  
Plastic Deformation ◽  
Dislocation Density ◽  
Crack Initiation ◽  
Yield Stress ◽  
Surface Integrity ◽  
Shot Peening ◽  
Experimental Result ◽  
Near Surface ◽  
Crystal Block

Shot peening is known to improve the fatigue performance of materials. The improvement in fatigue is that plastic deformation in the surface increases hardness, yield stress and microstrain of thinning Crystal block and dislocation density, and formed advantaged compress residual stress that are introduced into the near-surface of the components and which hinder crack initiation and growth. But over peening effect is produced when shot peening strengthening goes beyond a certain limit, which was adverse to improve surface quality. This paper adopted the optimization of the critical peening parameters to avoid appearing over peening effect. The experimental result showed that arc high value of optimal shot peening was 0.40mm.

Stored Energy of Plastic and Elastic Origin and Recrystallization

2008 ◽  
Vol 571-572 ◽  
pp. 143-148
Author(s):  
Krzysztof Wierzbanowski ◽  
Andrzej Baczmanski ◽  
Jacek Tarasiuk ◽  
Paul Lipiński ◽  
Alain Lodini
Keyword(s):  
Residual Stress ◽  
Plastic Deformation ◽  
Dislocation Density ◽  
Stress Field ◽  
Driving Force ◽  
Recrystallization Process ◽  
Stored Energy ◽  
Residual Stress Field ◽  
Orientation Distributions ◽  
Deformation Models

Stored energy is generally considered as a main driving force of recrystallization process. After plastic deformation a high dislocation density and residual stress field remain in a material. Both quantities are at the origin of the stored energy and we call them as the “plastic” and “elastic” parts of this energy. Their orientation distributions can be determined using diffraction and deformation models. Both components of the stored energy are studied in the present work. Their distributions and characteristics are studied for f.c.c. and b.c.c. materials.

Determination of Dislocation Density in Cubic Systems

2015 ◽  
Vol 812 ◽  
pp. 447-451
Author(s):  
Péter János Szabó ◽  
András Csóré
Keyword(s):  
Dislocation Density ◽  
The Other ◽  
Lattice Orientation ◽  
Five Elements ◽  
Cubic Systems

From the lattice orientation of a sample, elements of the Nye-tensor can be determined. With the help of Nye’s tensor, dislocation density can be calculated for the certain sample. Since the measures were carried out with scanning electronmicroscope (SEM), just superficial orientations can be measured. Hence the Nye-tensor is an incomplete matrix, with five elements. Because of the absence of the other four elements just a quasi-dislocation density can be obtained. The algorithm of the calculation was programmed on the language C#.

Measurement of residual stresses in beams and plates using the crack compliance technique

2000 ◽  
Vol 35 (4) ◽  
pp. 277-285 ◽  
Author(s):  
D Nowell ◽  
S Tochilin ◽  
D. A Hills
Keyword(s):  
Experimental Data ◽  
Residual Stress ◽  
Dislocation Density ◽  
Neutron Diffraction ◽  
Finite Thickness ◽  
Beam Theory ◽  
Kernel Functions ◽  
Surface Strain ◽  
Stress Fields ◽  
Strain Gauges

The crack compliance method provides a useful extension to the range of techniques available for the measurement of residual stress fields. The method is most suitable for simple geometries where the stresses vary in one direction only (e.g. usually depth). This paper describes the application of the dislocation density method to the calculation of the compliance functions required for the analysis of experimental data (the surface strain changes as a slot is cut). In particular, the kernel functions appropriate to a specimen of finite thickness (i.e. a beam or a plate) are given. The use of the technique for this geometry, including the use of multiple strain gauges, is discussed. Some sample results are given for the case of a plastically bent beam and these are compared with predictions from beam theory and with neutron diffraction measurements.

Influence of Plastic Pre-Strain on Low-Temperature Gas Carburization of 316L Austenitic Stainless Steel

2016 ◽  
Vol 853 ◽  
pp. 178-183 ◽  
Author(s):  
Ya Wei Peng ◽  
Jian Ming Gong ◽  
Yong Jiang ◽  
Ming Hui Fu ◽  
Dong Song Rong
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Low Temperature ◽  
Dislocation Density ◽  
Carbon Diffusion ◽  
Uniaxial Tensile ◽  
Engineering Strain ◽  
X Ray ◽  
316L Austenitic Stainless Steel

In this paper, the influence of pre-strain on low-temperature gas carburization of 316L austenitic stainless steel was investigated. A group of flat specimens were uniaxial tensile to several levels of pre-strain including 5%, 10%, 15%, 20% and 25% engineering strain. Then, the pre-strained specimens was treated by low-temperature gas carburization at 470 °C for 30 h. In order to elucidate the effect of pre-strain on low-temperature gas carburization, optical microscopy (OM), X-ray diffractometer (XRD), scanning electron probe micro-analyzer (EPMA), microhardness tester and residual stress analyzer were used. Meanwhile, dislocation density of the pre-strained specimens was semi-quantitatively measured by means of X-ray diffraction analysis and the role of dislocation density on carbon diffusion during low-temperature gas carburization was discussed. The results show as follow: (1) the thicknesses of the carburized layers are independent of the pre-strain degree. (2) dislocation density increases with the increasing pre-strain, but almost has no effect on carbon diffusion at the given carburizing temperature. (3) an outstanding surface with hardness (≈ 1150 HV0.1) and compressive residual stress (≈1900 MPa) is introduced by low-temperature gas carburization, and the strengthening results of carburization are unaffected by pre-strain.

Comparison of the GaAs Layers Grown on Porous Si and on Si by Molecular Beam Epitaxy

1989 ◽  
Vol 145 ◽  
Author(s):  
B.J. Wu ◽  
K.L. Wang ◽  
Y.J. Mii ◽  
Y.S. Yoon ◽  
A.T. Wu ◽  
...  
Keyword(s):  
Residual Stress ◽  
Molecular Beam Epitaxy ◽  
Dislocation Density ◽  
Thermal Annealing ◽  
Rapid Thermal Annealing ◽  
Molecular Beam ◽  
Porous Si ◽  
Si Substrate ◽  
Si Substrates

AbstractGaAs layers have been successfully grown on tilted (100) Si as well as porous Si substrates by molecular beam epitaxy(MBE). Rapid thermal annealing and vacuum thermal annealing have been used to further improve the quality of the epitaxial layers. We observed that the dislocation density near the interface of the heterostructure is higher for GaAs on Si substrate. Both annealing processes are proven to be useful in improving layer quality, while the vacuum thermal annealing seemed to be more effective in minimizing the residual stress.

Evaluation of intragranular strain and average dislocation density in single grains of a polycrystal using K-map scanning

2016 ◽  
Vol 49 (5) ◽  
pp. 1814-1817 ◽  
Author(s):  
Ernesto Filippelli ◽  
Gilbert Chahine ◽  
András Borbély
Keyword(s):  
Residual Stress ◽  
Dislocation Density ◽  
Three Dimensional ◽  
Tensile Load ◽  
Polycrystalline Materials ◽  
Strain Component ◽  
Reciprocal Space Mapping ◽  
X Ray ◽  
Average Dislocation Density ◽  
Single Grain

Quick scanning X-ray microscopy combined with three-dimensional reciprocal space mapping was applied to characterize intragranular orientation and strain in a single grain of uniaxially deformed Al polycrystal. The strain component perpendicular to the direction of the applied tensile load was found to be very heterogeneous with high compressive and tensile values in the grain interior and near two grain boundaries, respectively. The distribution of the magnitude of diffraction vectors indicates that dislocations are the origin of the strain. The work opens new possibilities for analysing dislocation structures and intragranular residual stress/strain in single grains of polycrystalline materials.

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