Application of the Three-Dimensional Damage Percolation Model and X-Ray Tomography for Damage Evolution Prediction in Aluminium Alloys

2006 ◽  
Vol 519-521 ◽  
pp. 1011-1016 ◽  
Author(s):  
O. Orlov ◽  
Éric Maire ◽  
Jérôme Adrien ◽  
Michael J. Worswick ◽  
David J. Lloyd
Keyword(s):  
Tensile Test ◽  
Damage Evolution ◽  
Void Nucleation ◽  
Sheet Material ◽  
Three Dimensional ◽  
Percolation Model ◽  
Second Phase ◽  
Material Damage ◽  
X Ray ◽  
Damage Initiation

A three-dimensional damage percolation model, which captures the effect of microstructural heterogeneity on damage evolution, has been developed to model damage initiation and propagation in materials containing second phase particles. It considers the three phenomena preceding ductile rupture of the material: void nucleation, growth, and coalescence. Threedimensional X-ray tomography is used to obtain measured three-dimensional second phase particle distributions in aluminum alloy sheet. Material damage evolution is studied within a tensile test simulation and compared to measured damage from an in situ tensile test utilizing X-ray tomography. Experimental and simulation results for material damage initiation and evolution are in good agreement.

Simulation of Damage Percolation Within Aluminum Alloy Sheet

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
O. S. Orlov ◽  
M. J. Worswick ◽  
E. Maire ◽  
D. J. Lloyd
Keyword(s):  
Aluminum Alloy ◽  
Void Nucleation ◽  
Phase Particle ◽  
Three Dimensional ◽  
Alloy Sheet ◽  
Void Coalescence ◽  
Second Phase ◽  
X Ray ◽  
Damage Initiation

A combined experimental and analytical approach is used to study damage initiation and evolution in three-dimensional second phase particle fields. A three-dimensional formulation of a damage percolation model is developed to predict damage nucleation and propagation through random-clustered second phase particle fields. The proposed approach is capable of capturing the three-dimensional character of damage phenomena and the three stages of ductile fracture, namely, void nucleation, growth, and coalescence, at the level of discrete particles. An in situ tensile test with X-ray tomography is utilized to quantify material damage during deformation in terms of the number of nucleated voids and porosity. The results of this experiment are used for both the development of a clustering-sensitive nucleation criterion and the validation of the damage percolation predictions. The evolution of damage in aluminum alloy AA5182 has been successfully predicted to match that in the in situ tensile specimen. Two forms of second phase particle field input data were considered: (1) that measured directly with X-ray tomography and (2) fields reconstructed statistically from two-dimensional orthogonal sections. It is demonstrated that the adoption of a cluster-sensitive void nucleation criterion, as opposed to a cluster-insensitive nucleation criterion, has a significant effect in promoting predicted void nucleation to occur within particle clusters. This behavior leads to confinement of void coalescence to within clusters for most of the duration of deformation followed by later development of a macrocrack through intracluster coalescence. The measured and reconstructed second phase particle fields lead to similar rates of predicted damage accumulation and can be used interchangeably in damage percolation simulations.

Nanoscale Three-Dimensional Microstructural Characterization of an Sn-Rich Solder Alloy Using High-Resolution Transmission X-Ray Microscopy (TXM)

2016 ◽  
Vol 22 (4) ◽  
pp. 808-813 ◽  
Author(s):  
Chandrashekara S. Kaira ◽  
Carl R. Mayer ◽  
V. De Andrade ◽  
Francesco De Carlo ◽  
Nikhilesh Chawla
Keyword(s):  
Fresnel Zone ◽  
Three Dimensional ◽  
Microstructural Characterization ◽  
Second Phase ◽  
Full Field ◽  
X Ray ◽  
Second Phase Particles ◽  
Rich Alloy ◽  
Nanoscale Features

AbstractThree-dimensional (3D) nondestructive microstructural characterization was performed using full-field transmission X-ray microscopy on an Sn-rich alloy, at a spatial resolution of 60 nm. This study highlights the use of synchrotron radiation along with Fresnel zone plate optics to perform absorption contrast tomography for analyzing nanoscale features of fine second phase particles distributed in the tin matrix, which are representative of the bulk microstructure. The 3D reconstruction was also used to quantify microstructural details of the analyzed volume.

Micro-Mechanics of Creep-Fatigue Damage in PB-SN Solder Due to Thermal Cycling—Part I: Formulation

2002 ◽  
Vol 124 (3) ◽  
pp. 292-297 ◽  
Author(s):  
Pradeep Sharma ◽  
Abhijit Dasgupta
Keyword(s):  
Fatigue Damage ◽  
Damage Mechanics ◽  
Void Nucleation ◽  
Cyclic Creep ◽  
Diffusional Creep ◽  
Void Coalescence ◽  
Second Phase ◽  
Structural Stress ◽  
Damage Initiation ◽  
Creep Fatigue

This paper presents a micro-mechanistic approach for modeling fatigue damage initiation due to cyclic creep in eutectic Pb-Sn solder. Damage mechanics due to cyclic creep is modeled with void nucleation, void growth, and void coalescence model based on micro-structural stress fields. Micro-structural stress states are estimated under viscoplastic phenomena like grain boundary sliding, its blocking at second-phase particles, and diffusional creep relaxation. In Part II of this paper, the developed creep-fatigue damage model is quantified and parametric studies are provided to better illustrate the utility of the developed model.

Investigation of Microcrack Growth in [0/90]s Composite Laminates

2003 ◽  
Author(s):  
Melody A. Verges ◽  
Paul J. Schilling ◽  
Paul D. Herrington ◽  
Arun K. Tatiparthi
Keyword(s):  
Optical Microscopy ◽  
Composite Laminates ◽  
Damage Evolution ◽  
Applied Load ◽  
Three Dimensional ◽  
Three Dimensions ◽  
X Ray ◽  
Computed Microtomography ◽  
X Ray Computed ◽  
Microcrack Growth

Techniques such as optical microscopy and X-radiography have provided useful information regarding damage in composite laminates, particular in therms of microcracking behavior in individual plies. This focuses on the investigation of microcracking and damage evolution in loaded composite laminates via X-ray computed microtomography. The main advantage in the use of such a technique is that damage within the composite can be assessed in three-dimensions without destruction of the composite. In this work, IM7/977–2, IM7/5555, and IM7/5276-1 coupons were uniaxially tested in a tensile substage, Graphs that convey microcracking density information as a function of applied load were created for [0/90/90/0] laminates. The three dimensional geometry and connectivity of microcracks and other damage in these samples were investigated through microtomographic reconstruction.

High-resolution three-dimensional mapping of individual grains in polycrystals by topotomography

2007 ◽  
Vol 40 (5) ◽  
pp. 905-911 ◽  
Author(s):  
Wolfgang Ludwig ◽  
Erik Mejdal Lauridsen ◽  
Soeren Schmidt ◽  
Henning Friis Poulsen ◽  
José Baruchel
Keyword(s):  
Grain Shape ◽  
Three Dimensional ◽  
Projection Data ◽  
Second Phase ◽  
Additional Contribution ◽  
Beam Position ◽  
Transmitted Beam ◽  
X Ray ◽  
Three Dimensional Mapping ◽  
Dimensional Mapping

By orienting a crystal grain with its diffraction vector along the sample rotation axis, it is possible to use powerful tomographic and topographic imaging techniques to reconstruct the three-dimensional grain shape inside a polycrystalline sample. The acquisition and reconstruction can be performed from projection images with the detector positioned either in the diffracted-beam or in the direct-beam position. In the first case, the projection data consist of a series of integrated, monochromatic beam X-ray diffraction topographs of the grain under investigation. In the second case, the corresponding diffraction contrast in the transmitted beam may be interpreted as an additional contribution to the X-ray attenuation coefficient of the material. This latter variant is restricted to grains with small orientation spread but offers the possibility to characterize simultaneously the three-dimensional grain shape and the absorption microstructure of the surrounding sample material. The contrast mechanism is sensitive to local strain fields and can, in certain cases, reveal details of the grain microstructure, such as the presence of second-phase inclusions. The methodology is successfully demonstrated on an aluminium polycrystal, with a resulting three-dimensional mapping accuracy better than 7 µm. The possibilities and limitations of the technique are listed and its performance relative to other three-dimensional mapping techniques is discussed.

Three-Dimensional Micron-Resolution X-Ray Laue Diffraction Measurement of Thermal Grain-Evolution in Aluminum

2004 ◽  
Vol 467-470 ◽  
pp. 1373-1378 ◽  
Author(s):  
J.D. Budai ◽  
W. Yang ◽  
B.C. Larson ◽  
J.Z. Tischler ◽  
W. Liu ◽  
...  
Keyword(s):  
Grain Growth ◽  
Lattice Structure ◽  
Three Dimensional ◽  
Automated Analysis ◽  
Grain Structure ◽  
Polycrystalline Materials ◽  
Second Phase ◽  
Diffraction Measurement ◽  
X Rays ◽  
X Ray

A new technique for investigating 3D grain growth in polycrystalline materials using white x-ray microdiffraction with micron point-to-point spatial resolution is presented. This technique utilizes focused polychromatic x-rays at the Advanced Photon Source, differential aperture depth-profiling, CCD measurements, and automated analysis of spatially-resolved Laue patterns to measure local lattice structure and orientation. 3D thermal grain growth studies of hotrolled aluminum have been initiated to demonstrate the capabilities of this method. Complete 3D grain orientation maps were obtained from a hot-rolled aluminum polycrystal. The sample was then annealed to induce grain growth, cooled to room temperature, and re-mapped to measure the thermal migration of all grain boundaries within the same volume region. Initial observations reveal significant grain growth above 360°C, involving movement of both low- and high-angle boundaries. Systematic measurements have been obtained of the as-rolled grain structure and of the microstructural evolution after annealing at successively higher temperatures. Small second-phase precipitates have been identified. Such measurements will provide the detailed 3D experimental link needed for testing theories and computer models of 3D grain growth in bulk materials.

Ribosome Structural Organization

1974 ◽  
Vol 32 ◽  
pp. 332-333
Author(s):  
James A. Lake
Keyword(s):  
Ribosomal Proteins ◽  
Structural Organization ◽  
Three Dimensional ◽  
Small Subunit ◽  
Structural Studies ◽  
X Ray Diffraction ◽  
Specific Antibodies ◽  
X Ray ◽  
E Coli ◽  
Complete Sequences

The understanding of ribosome structure has advanced considerably in the last several years. Biochemists have characterized the constituent proteins and rRNA's of ribosomes. Complete sequences have been determined for some ribosomal proteins and specific antibodies have been prepared against all E. coli small subunit proteins. In addition, a number of naturally occuring systems of three dimensional ribosome crystals which are suitable for structural studies have been observed in eukaryotes. Although the crystals are, in general, too small for X-ray diffraction, their size is ideal for electron microscopy.

3-D reconstruction of molecular shape from microcrystal thin sections

1983 ◽  
Vol 41 ◽  
pp. 748-749
Author(s):  
S. Cusack ◽  
J.-C. Jésior
Keyword(s):  
Three Dimensional ◽  
Molecular Shape ◽  
Biological Molecules ◽  
Fourier Space ◽  
Single Particles ◽  
Thin Sections ◽  
Standard Methods ◽  
X Ray ◽  
X Ray Crystallography ◽  
Dimensional Reconstruction

Three-dimensional reconstruction techniques using electron microscopy have been principally developed for application to 2-D arrays (i.e. monolayers) of biological molecules and symmetrical single particles (e.g. helical viruses). However many biological molecules that crystallise form multilayered microcrystals which are unsuitable for study by either the standard methods of 3-D reconstruction or, because of their size, by X-ray crystallography. The grid sectioning technique enables a number of different projections of such microcrystals to be obtained in well defined directions (e.g. parallel to crystal axes) and poses the problem of how best these projections can be used to reconstruct the packing and shape of the molecules forming the microcrystal.Given sufficient projections there may be enough information to do a crystallographic reconstruction in Fourier space. We however have considered the situation where only a limited number of projections are available, as for example in the case of catalase platelets where three orthogonal and two diagonal projections have been obtained (Fig. 1).

X-ray microtomography

1988 ◽  
Vol 46 ◽  
pp. 998-999
Author(s):  
H.W. Deckman ◽  
B.F. Flannery ◽  
J.H. Dunsmuir ◽  
K.D' Amico
Keyword(s):  
Computed Tomography ◽  
Internal Structure ◽  
Imaging Technique ◽  
Three Dimensional ◽  
Tissue Structure ◽  
Individual Element ◽  
X Ray ◽  
Non Invasive ◽  
Panoramic Imaging ◽  
Three Dimensional Images

We have developed a new X-ray microscope which produces complete three dimensional images of samples. The microscope operates by performing X-ray tomography with unprecedented resolution. Tomography is a non-invasive imaging technique that creates maps of the internal structure of samples from measurement of the attenuation of penetrating radiation. As conventionally practiced in medical Computed Tomography (CT), radiologists produce maps of bone and tissue structure in several planar sections that reveal features with 1mm resolution and 1% contrast. Microtomography extends the capability of CT in several ways. First, the resolution which approaches one micron, is one thousand times higher than that of the medical CT. Second, our approach acquires and analyses the data in a panoramic imaging format that directly produces three-dimensional maps in a series of contiguous stacked planes. Typical maps available today consist of three hundred planar sections each containing 512x512 pixels. Finally, and perhaps of most import scientifically, microtomography using a synchrotron X-ray source, allows us to generate maps of individual element.

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