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 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.

Recovery of HPT-Processed Iron Studied by Orientation Imaging Microscopy

2007 ◽  
Vol 558-559 ◽  
pp. 891-896
Author(s):  
Julia Ivanisenko ◽  
Alexander Minkow ◽  
Ruslan Valiev ◽  
Hans Jorg Fecht
Keyword(s):  
Microstructure Evolution ◽  
Orientation Imaging Microscopy ◽  
Xrd Analysis ◽  
Comprehensive Investigation ◽  
Recovery Mechanism ◽  
Orientation Imaging ◽  
Subgrain Growth ◽  
Nanocrystalline Iron ◽  
Mean Size ◽  
Very High

A comprehensive investigation of microstructure evolution upon annealing in the temperature range between 100°C and 450°C in SPD-processed nanocrystalline iron had been conducted using transmission and orientation imaging microscopy, and XRD analysis. The asprocessed microstructure was typical of severely deformed metals consisting of grains with a mean size of 110 nm, each subdivided by a network of subgrain boundaries. Additionally, measurements of microstrains using XRD found a very high microstrain level of 0.003 in this material. After annealing at 200°C a drastic decrease of microstrains was observed; whereas no notable changes in the size of grains and subgrains as well in misorientation spectra have been revealed. Thus we relate this decrease of microstrains with recovery of non-equilibrium grain boundaries. Annealing at higher temperatures hadn’t led to further decrease of microstrains, but resulted in slight subgrain growth from 65 to 78 nm accompanied by increase of mean misorientation angle from 5° to 6.3°at 450°C. This indicates the occurrence of coalescence of subgrains as additional recovery mechanism.

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.

An Investigation of the Influence of Orientation on CMP through Nanoscratch Testing

2009 ◽  
Vol 1157 ◽  
Author(s):  
Sarah Neyer ◽  
Burak Ozdoganlar ◽  
C. Fred Higgs
Keyword(s):  
Material Removal Rate ◽  
Integrated Circuit ◽  
Material Removal ◽  
Removal Rate ◽  
Orientation Imaging Microscopy ◽  
Orientation Dependence ◽  
Orientation Imaging ◽  
Ic Manufacturing ◽  
Crystallographic Planes ◽  
Scratch Tests

AbstractWith the increase in integrated circuit (IC) feature density, the quality of chemical mechanical polishing (CMP) becomes more important as the copper interconnects decrease in size. The optimization of the IC manufacturing process will be greatly enhanced if the nanoscale effects on CMP are better understood. CMP-related wear at the sub-micron scale, where a single particle affects the microstructure of individual copper features within the substrate, needs to be investigated to account for wafer-scale variations. Hardness is known to affect the material removal rate, but the grain level mechanism of the removal process is not yet well known. In this work, the orientation-dependence of wear has been investigated by performing nanoscale scratch tests on single crystal copper along different crystallographic planes, indentified using orientation imaging microscopy (OIM). An analysis of the surface forces and post-scratch topography produced during the scratch tests was conducted and the results have been interpreted from a CMP perspective. Ultimately, these results are expected to refine existing material removal rate models which do not consider the sensitivity of microstructure on the CMP process.

Recognizing Job Apathy Patterns of Iraqi Higher Education Employees Using Data Mining Techniques

2019 ◽  
Vol 54 (4) ◽  
Author(s):  
Mustafa S. Abd ◽  
Suhad Faisal Behadili
Keyword(s):  
Higher Education ◽  
Data Mining ◽  
Psychiatric Patients ◽  
Human Life ◽  
A Priori ◽  
Psychological Research ◽  
Attribute Selection ◽  
Specific Class ◽  
Data Mining Techniques ◽  
Using Data

Psychological research centers help indirectly contact professionals from the fields of human life, job environment, family life, and psychological infrastructure for psychiatric patients. This research aims to detect job apathy patterns from the behavior of employee groups in the University of Baghdad and the Iraqi Ministry of Higher Education and Scientific Research. This investigation presents an approach using data mining techniques to acquire new knowledge and differs from statistical studies in terms of supporting the researchers’ evolving needs. These techniques manipulate redundant or irrelevant attributes to discover interesting patterns. The principal issue identifies several important and affective questions taken from a questionnaire, and the psychiatric researchers recommend these questions. Useless questions are pruned using the attribute selection method. Moreover, pieces of information gained through these questions are measured according to a specific class and ranked accordingly. Association and a priori algorithms are used to detect the most influential and interrelated questions in the questionnaire. Consequently, the decisive parameters that may lead to job apathy are determined.

Optimization of μEDM process assisted with rotating magnetic pulling force and ultrasonic vibration

2021 ◽  
pp. 095440892098440
Author(s):  
Gurpreet Singh ◽  
DR Prajapati ◽  
PS Satsangi
Keyword(s):  
Ultrasonic Vibration ◽  
Material Removal Rate ◽  
Electrical Discharge ◽  
Material Removal ◽  
Electrical Discharge Machining ◽  
Removal Rate ◽  
Machining Process ◽  
Micro Electrical Discharge Machining ◽  
Pulling Force ◽  
Tool Rotation

The micro-electrical discharge machining process is hindered by low material removal rate and low surface quality, which bound its capability. The assistance of ultrasonic vibration and magnetic pulling force in micro-electrical discharge machining helps to overcome this limitation and increase the stability of the machining process. In the present research, an attempt has been made on Taguchi based GRA optimization for µEDM assisted with ultrasonic vibration and magnetic pulling force while µEDM of SKD-5 die steel with the tubular copper electrode. The process parameters such as ultrasonic vibration, magnetic pulling force, tool rotation, energy and feed rate have been chosen as process variables. Material removal rate and taper of the feature have been selected as response measures. From the experimental study, it has been found that response output measures have been significantly improved by 18% as compared to non assisted µEDM. The best optimal combination of input parameters for improved performance measures were recorded as machining with ultrasonic vibration (U1), 0.25 kgf of magnetic pulling force (M1), 600 rpm of tool rotation (R2), 3.38 mJ of energy (E3) and 1.5 mm/min of Tool feed rate (F3). The confirmation trail was also carried out for the validation of the results attained by Grey Relational Analysis and confirmed that there is a substantial improvement with both assistance applied simultaneously.

scholarly journals Simulation of the ductile machining mode of silicon

2021 ◽  
Author(s):  
Hagen Klippel ◽  
Stefan Süssmaier ◽  
Matthias Röthlin ◽  
Mohamadreza Afrasiabi ◽  
Uygar Pala ◽  
...  
Keyword(s):  
Brittle Material ◽  
Material Removal ◽  
Machining Process ◽  
Ductile Material ◽  
Diamond Wire ◽  
Ductile Machining ◽  
Mesh Free ◽  
Diamond Wire Sawing ◽  
Material Removal Mode ◽  
Brittle Material Removal

AbstractDiamond wire sawing has been developed to reduce the cutting loss when cutting silicon wafers from ingots. The surface of silicon solar cells must be flawless in order to achieve the highest possible efficiency. However, the surface is damaged during sawing. The extent of the damage depends primarily on the material removal mode. Under certain conditions, the generally brittle material can be machined in ductile mode, whereby considerably fewer cracks occur in the surface than with brittle material removal. In the presented paper, a numerical model is developed in order to support the optimisation of the machining process regarding the transition between ductile and brittle material removal. The simulations are performed with an GPU-accelerated in-house developed code using mesh-free methods which easily handle large deformations while classic methods like FEM would require intensive remeshing. The Johnson-Cook flow stress model is implemented and used to evaluate the applicability of a model for ductile material behaviour in the transition zone between ductile and brittle removal mode. The simulation results are compared with results obtained from single grain scratch experiments using a real, non-idealised grain geometry as present in the diamond wire sawing process.

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.

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