Application of a Crystal Orientation Method for Matching Surfaces Along a Fracture Line

2008 ◽  
Author(s):  
Barbara K. Lograsso ◽  
Thomas A. Lograsso ◽  
Ryan J. Glamm
Keyword(s):  
Crystal Orientation ◽  
Orientation Imaging Microscopy ◽  
Fracture Plane ◽  
Orientation Imaging ◽  
Metal Fracture ◽  
Single Piece ◽  
Orientation Method ◽  
Electron Back Scattered Diffraction ◽  
Actual Fracture

The overall objective of this study was to evaluate whether surface crystal orientation can be used to associate metal fracture fragments. This study examined the orientations of the fractured crystals across the fracture plane for two surfaces determined to be a matching fracture by conventional methods. This study used Electron Back-Scattered Diffraction (EBSD), sometimes known as Orientation Imaging Microscopy (OIM), to determine the crystallographic orientation of individual metal crystals along the length of the fracture on a surface perpendicular to the actual fracture surface. This investigation examined the uniqueness of crystal orientations within a metal and examined the requirements necessary for determination of crystallography using EBSD. This study also examined the crystallographic information as to whether it is sufficiently reliable characteristic from which a quantitative determination could be made that two separate pieces of metal are, in fact, from a single piece.

Modeling Evolution of Microstructures Beneath Topographically Textured Surfaces Produced Using Shear Based Material Removal

2016 ◽  
Author(s):  
Saurabh Basu ◽  
Zhiyu Wang ◽  
Christopher Saldana
Keyword(s):  
Microstructure Evolution ◽  
Material Removal ◽  
A Priori ◽  
Orientation Imaging Microscopy ◽  
Machining Process ◽  
Textured Surfaces ◽  
Orientation Imaging ◽  
Using Data ◽  
Electron Back Scattered Diffraction ◽  
Tool Chatter

Tool chatter is envisaged as a technique to create undulations on fabricated biomedical components. Herein, a-priori designed topographies were fabricated using modulate assisted machining of oxygen free high conductivity copper. Subsequently, underpinnings of microstructure evolution in this machining process were characterized using electron back scattered diffraction based orientation imaging microscopy. These underpinnings were related to the unsteady mechanical states present during modulated assisted machining, this numerically modeled using data obtained from simpler machining configurations. In this manner, relationships between final microstructural states and the underlying mechanics were found. Finally, these results were discussed in the context of unsteady mechanics present during tool chatter, it was shown that statistically predictable microstructural outcomes result during tool chatter.

Application of Crystal Orientation Mapping to Intra-Grain Misorientations

1997 ◽  
Vol 3 (S2) ◽  
pp. 563-564
Author(s):  
Robert Davies ◽  
Valerie Randlè
Keyword(s):  
Crystal Orientation ◽  
Orientation Imaging Microscopy ◽  
Electron Back Scatter Diffraction ◽  
Pure Aluminium ◽  
Orientation Imaging ◽  
Orientation Mapping ◽  
Black Pixel ◽  
Ebsd Pattern ◽  
Crystal Orientation Mapping ◽  
Scanning Electron

Crystal orientation mapping (COM), which is also referred to as orientation imaging microscopy (OIM), is a powerful tool which opens up enormous possibilities for investigation of materials. The principle of COM is that the microstructure is displayed or mapped according to the orientation of sampled volumes of crystal. These data are obtained in the scanning electron microscope by moving either the electron beam or the specimen stage through predetermined steps and collecting an electron back-scatter diffraction (EBSD) pattern. Typically, a null orientation is represented by a black pixel and colours are used to depict orientations, thus allowing discrete orientation changes such as grain boundaries to be plotted directly in a map format. This is exemplified in figure 1 which shows an orientation map generated from pure aluminium which has undergone 5% cold rolling. The diffiiseness of EBSD patterns further permits strain changes to be mapped.

Orientation imaging studies of Sn-based electronic solder joints

2002 ◽  
Vol 17 (9) ◽  
pp. 2294-2306 ◽  
Author(s):  
A. A. Telang ◽  
T. T. Bieler ◽  
S. Choi ◽  
K. K. Subramanian
Keyword(s):  
Crystal Orientation ◽  
Room Temperature ◽  
Solder Joints ◽  
High Strain ◽  
Orientation Imaging Microscopy ◽  
Grain Boundary Sliding ◽  
Temperature History ◽  
Orientation Imaging ◽  
Boundary Sliding ◽  
Free Solder

Single shear lap specimens were subjected to creep, isothermal aging, and thermomechanical fatigue (TMF). Scanning electron microscopy micrographs of previously polished specimens revealed changes in surface morphology. Orientation imaging microscopy was carried out on the same specimens to study the microstructural evolution and crystal orientation changes. As-fabricated joints consistently show a preferred crystal orientation with a few minority orientations with highly preferred misorientations. Alloy additions caused an increase in the number of statistically significant crystal orientations and misorientations. The solidification microstructure was unchanged due to room-temperature creep. Aging caused development and motion of well-defined subgrain boundaries and removal of most minority orientations. TMF causes heterogeneous refinement of the microstructure that accounts for the localized grain boundary sliding in regions of high strain concentration. This study implies that the lead-free solder joints are not polycrystals, but multicrystals, so that deformation is very heterogeneous and sensitive to strain and temperature history.

Recovery and Recrystallization Study after Low Deformation Amount by Cold Rolling in an IF-Ti Steel

2004 ◽  
Vol 467-470 ◽  
pp. 183-188 ◽  
Author(s):  
Amel Samet-Meziou ◽  
Anne Laure Etter ◽  
Thierry Baudin ◽  
Richard Penelle
Keyword(s):  
Cold Rolling ◽  
Boundary Migration ◽  
Orientation Imaging Microscopy ◽  
Continuous Growth ◽  
Orientation Imaging ◽  
Transmission Electron ◽  
Deformation Amount ◽  
Deformed State ◽  
Electron Back Scattered Diffraction

The first steps of recovery and recrystallization in an IF-Ti steel after 40% cold rolling have been studied using the Electron Back Scattered Diffraction (EBSD), Orientation Imaging Microscopy(™) (OIM) and the Transmission Electron Microscopy (TEM). As it is well known, for low deformation amounts by cold rolling, recrystallization texture exhibits the g fiber (ND // <111>) with a reinforcement of the {111}<110> orientation. In order to understand this {111}<110> development during recrystallization, characterization of the deformed state was performed. Different microstructures were distinguished: lamellar bands for the {111}<112> grains of the g fiber and coarse elongated cells for the {111}<110> orientation that belongs to the a and g fibers. Whatever the initial dislocation structure, the recovery step seems to be characterized by coalescence and growth of existing cells in the recovered matrix. Then nucleus growth seems to occur by sub-boundary migration. The first steps of recrystallization mainly take place by continuous growth of subgrains including or not the bulging of grain boundaries.

Recrystallization in an IF-Ti Steel after Low Deformation Amount by Tensile Strain

2005 ◽  
Vol 495-497 ◽  
pp. 1297-1302
Author(s):  
Amel Samet-Meziou ◽  
Anne Laure Etter ◽  
Thierry Baudin ◽  
Richard Penelle
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cell Walls ◽  
Tensile Strain ◽  
Orientation Imaging Microscopy ◽  
Continuous Growth ◽  
Orientation Imaging ◽  
Transmission Electron ◽  
Deformation Amount ◽  
Electron Back Scattered Diffraction

The first steps of recovery and recrystallization in an IF-Ti steel after 35% deformation by uniaxial tension have been studied by Electron Back Scattered Diffraction (EBSD), Orientation Imaging Microscopy(™) (OIM) and Transmission Electron Microscopy (TEM). Two types of substructure are created after tensile strain: diamond shaped cells for the {111}<110> component and equiaxed cells for {001}<110> component. The recovery is by the decrease of dislocation density inside cells, the refinement of the cell walls, the vanishing of the cell wall, the cell coalescence and the cell growth. Recrystallized grains developed by two main recrystallization mechanisms: the “generalized recovery” and the “bulging”. Both mechanisms are based on continuous growth of subgrains followed or not by the migration of the prior grain boundaries.

Influence of Dynamic Recrystallisation on Texture Formation in ECAP deformed Nickel

2007 ◽  
Vol 558-559 ◽  
pp. 575-580 ◽  
Author(s):  
Werner Skrotzki ◽  
Burghardt Klöden ◽  
I. Hünsche ◽  
Robert Chulist ◽  
Satyam Suwas ◽  
...  
Keyword(s):  
Orientation Imaging Microscopy ◽  
High Energy ◽  
Texture Gradient ◽  
Texture Formation ◽  
Microstructure Formation ◽  
Fcc Metals ◽  
Orientation Imaging ◽  
Angular Pressing ◽  
Dynamic Recrystallisation ◽  
Number Of Passes

3N nickel has been deformed by equal channel angular pressing (ECAP) at 400°C up to 3 passes using route A. The texture with respect to position in the deformed billet, i.e. from top to bottom, has been measured with high-energy synchrotron radiation. It is characterized by texture components typical for simple shear in the intersection plane of the square-shaped 90° bent channel. Besides, an oblique cube component is observed. Orientation imaging microscopy clearly shows that this component is due to partial recrystallization. Intensities of the texture components as well as deviations from their ideal shear positions vary from the top to the bottom of the billet and with the number of passes. The change of the intensity of texture components and the texture gradient investigated is discussed. Special emphasis is put on the influence of dynamic recrystallization on texture and microstructure formation during ECAP of fcc metals.

Ultra Grain Refinement of Low C Steels by Accumulative Roll Bonding

2006 ◽  
Vol 503-504 ◽  
pp. 311-316 ◽  
Author(s):  
I. Salvatori
Keyword(s):  
Accumulative Roll Bonding ◽  
Orientation Imaging Microscopy ◽  
Low Carbon Steel ◽  
Small Samples ◽  
Low Carbon ◽  
High Angle ◽  
Misorientation Distribution ◽  
Roll Bonding ◽  
Orientation Imaging ◽  
Annealing Conditions

Refinement of grain size is one of the biggest challenges to produce steels with improved combination of strength and toughness. Ultrafine structures are being produced world-wide on various materials, including low carbon steel, using different types of processes. However, the majority of these processes also exhibit severe limitations because they are generally restricted to small samples and are difficult to be implemented on an industrial scale. A promising technique for industrial implementation is the Accumulative Roll Bonding (ARB), a process able to supply large samples, even in the laboratory scale. In this paper, warm intense straining (ε = 4) by ARB was applied to a plain low-C steel in order to develop ultrafine grains, aiming at sizes around 1-2 μm, suitable to maintain an adequate combination of strength and ductility. The effect of annealing conditions on the evolution of the work-hardened microstructure and the bonding behaviour after each pass were investigated. Orientation Imaging Microscopy was used to investigate the microstructure and give a quantitative assessment of high angle and low angle boundaries. It is showed that the frequency of high angle grain boundaries increases with the strain but the misorientation distribution remained far from that typical of a recrystallised material.

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