Micro-level Clearance Punching on NGO Electrical Steel

2020 ◽  
Vol 142 (8) ◽  
Author(s):  
Zhenglong Fang ◽  
Keisuke Nagato ◽  
Tomohito Shimura ◽  
Masato Murakami ◽  
Masayuki Nakao
Keyword(s):  
Plastic Strain ◽  
Electrical Steel ◽  
Electron Backscatter Diffraction ◽  
Dimensional Accuracy ◽  
Magnetic Core ◽  
Micro Level ◽  
Shear Speed ◽  
Backscatter Diffraction ◽  
Cut Surface

Abstract Non-grain-oriented electrical steel lamination is a critical component for the magnetic core. Punching such steel sheet with a large shear region, a low burr and small rollover is required to ensure accuracy. Densely packed grain deformation and plastic strain near cut surface are generally accompanied which detrimentally influence magnetic properties. In this study, micro-clearance (CL: 1 and 5 µm) punching of electrical silicon steel was conducted to investigate the influences of punching speed, micro-clearance, and counterforce on dimensional accuracy and microstructural changes. Electron backscatter diffraction analysis was performed to investigate the microstructural characteristics and detailed texture of specimens produced by shear speeds of 100, 260, and 600 mm/s with and without applied counterforce. Rollover height was found to be significantly reduced at a shear speed of 260 mm/s with applied counterforce under 1 µm clearance punching. The applications of counterforce and higher speed both significantly increased grain deformation, although the dimensional accuracy was improved. Grain conditions and the quality of cut surface were compared for different punching conditions to advance the understanding on the correlations between dimensional accuracy, grain deformation, and plastic strain.

Modelling of Fine Blanking Process of the Aluminium Sheets

2011 ◽  
Vol 473 ◽  
pp. 290-297 ◽  
Author(s):  
Wojciech Wieckowski ◽  
Piotr Lacki ◽  
Janina Adamus
Keyword(s):  
Dimensional Accuracy ◽  
Soft Materials ◽  
Fine Blanking ◽  
Technological Quality ◽  
Aluminium Sheets ◽  
The Impact ◽  
Blanking Process ◽  
Cut Surface ◽  
Stress And Strain Distribution

The required technological quality of the blanked products can be achieved through operations of fine blanking. This allows for obtaining products with improved dimensional accuracy and good quality cut-surface. In order to cut products from soft materials, including aluminium and its alloys, the methods of fine blanking with upsetting and fine blanking with reduced clearance are typically employed. The study presents the results of numerical modelling of the fine blanking process for a disk made of 1-millimetre sheet aluminium EN AW-1070A. The goal of the numerical simulations was to evaluate the effect of clearance between blanking die and the punch, and the impact of V-ring indenter on stress and strain distribution in the shearing zone.

scholarly journals Non-Modulated Martensite Microstructure With Internal Nanotwins In Ni-Mn-Ga Alloys

2015 ◽  
Vol 60 (3) ◽  
pp. 2267-2270 ◽  
Author(s):  
M.J. Szczerba
Keyword(s):  
Electron Backscatter Diffraction ◽  
Martensite Plate ◽  
The Self ◽  
The Third ◽  
Incoherent Interface ◽  
Electron Backscatter ◽  
Micro Level ◽  
Backscatter Diffraction ◽  
Martensite Microstructure ◽  
Scanning Electron

Abstract The self-accommodated non-modulated martensite of Ni-Mn-Ga single crystal was studied by transmission and scanning electron microscopy in the latter case using the electron backscatter diffraction technique. Three kinds of interfaces existing at different length scales were reported. The first, is the wavy and incoherent interface separating martensite variants observed on the micro-level with no-common crystallographic plane between them. The second is within a single martensite plate where the lattice rotates around one of the {110} pole to accommodate the interfacial curvature between martensite plates. Finally, at the nanoscale the third interface exists, a twin boundary separating internal nanotwins with the {112} type habit plane.

A Review of Strain Analysis Using Electron Backscatter Diffraction

2011 ◽  
Vol 17 (3) ◽  
pp. 316-329 ◽  
Author(s):  
Stuart I. Wright ◽  
Matthew M. Nowell ◽  
David P. Field
Keyword(s):  
Plastic Strain ◽  
Materials Science ◽  
Electron Backscatter Diffraction ◽  
Strain Analysis ◽  
Current State ◽  
Mapping Parameters ◽  
Submicron Scale ◽  
Electron Backscatter ◽  
Ebsd Technique ◽  
Backscatter Diffraction

AbstractSince the automation of the electron backscatter diffraction (EBSD) technique, EBSD systems have become commonplace in microscopy facilities within materials science and geology research laboratories around the world. The acceptance of the technique is primarily due to the capability of EBSD to aid the research scientist in understanding the crystallographic aspects of microstructure. There has been considerable interest in using EBSD to quantify strain at the submicron scale. To apply EBSD to the characterization of strain, it is important to understand what is practically possible and the underlying assumptions and limitations. This work reviews the current state of technology in terms of strain analysis using EBSD. First, the effects of both elastic and plastic strain on individual EBSD patterns will be considered. Second, the use of EBSD maps for characterizing plastic strain will be explored. Both the potential of the technique and its limitations will be discussed along with the sensitivity of various calculation and mapping parameters.

On the Production of Randomly-Oriented Recrystallization Nuclei for Selective Growth Experiments

2004 ◽  
Vol 467-470 ◽  
pp. 165-170 ◽  
Author(s):  
Mark D. Nave ◽  
Kim Verbeken ◽  
Leo Kestens
Keyword(s):  
Electron Backscatter Diffraction ◽  
Selective Growth ◽  
Stored Energy ◽  
The Matrix ◽  
Deformed Layer ◽  
Deformation Processes ◽  
Backscatter Diffraction ◽  
Cut Surface ◽  
Growth Experiments ◽  
The Ideal

The ideal starting condition for selective growth experiments is one having a layer of randomly-oriented nuclei adjacent to a matrix with negligible orientational variation but sufficient stored energy to promote growth. In practice, cutting or deformation processes are used in an attempt to approximate these ideal conditions, but the degree to which this is achieved has not been rigorously quantified. In this work, Fe-3wt%Si single crystals were cut or deformed using six different processes. The variation in texture with distance from the cut or deformed surface was measured using electron backscatter diffraction (EBSD) in a field emission gun scanning electron microscope (FEG-SEM) in order to assess the ability of each process to create conditions suitable for selective growth experiments. While grooving with a machine tool produced the best spread of orientations at the cut surface, the suitability of this process is diminished by the presence of a differently-textured deformed layer between the cut surface and the single crystal matrix. Grinding produced a less ideal distribution of orientations at the cut surface, but the presence of these orientations in a very thin layer adjacent to the matrix makes this process preferable for preparing crystals for selective growth experiments, provided the results are corrected for the deviation in the distribution of nuclei orientations from a random distribution.

Influence of Bonding Pressure on the Mechanical Properties of Copper Bumps

2012 ◽  
Author(s):  
S. M. L. Nai ◽  
H. J. Lu ◽  
C. K. Cheng ◽  
J. Wei
Keyword(s):  
Mechanical Properties ◽  
Electron Backscatter Diffraction ◽  
Bonding Temperature ◽  
Threshold Value ◽  
Bonding Pressure ◽  
Thermocompression Bonding ◽  
The Individual ◽  
Backscatter Diffraction

Thermocompression bonding is one of the key ways to form interconnections in many hetegrogeneous devices. The quality of metallic joints formed using thermocompression is predominantly determined by the bonding temperature and pressure. In order to achieve a strong and reliable joint, metallic joints in particular copper, which has an oxidative nature, require a high bonding temperature (> 300 °C). However, thermomechanical-related stresses induced during bonding can compromise the performance of the interconnections in the long term. Thus, one way to manage this is to lower the bonding temperature used in forming the interconnections. In this study, copper-copper bonding is successfully demonstrated at a bonding temperature of 80 °C. In order to better understand the effect of bonding pressure on the joint’s performance, the mechanical properties of the individual bulk copper bumps are evaluated using the nanoindentation system. Studies are conducted on the bulk copper bumps subjected to different bonding pressures. Their corresponding yield strength and hardness results are then determined. It is observed that as the applied bonding pressure increases, the mechanical properties of the bulk copper bump reach a certain threshold value and beyond which, properties start to degrade. The microstructure and grain sizes of the copper bumps are also analyzed using the electron backscatter diffraction.

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