In Situ Electron Backscatter Diffraction Investigation of Recrystallization in a Copper Wire

2013 ◽  
Vol 19 (4) ◽  
pp. 969-977 ◽  
Author(s):  
François Brisset ◽  
Anne-Laure Helbert ◽  
Thierry Baudin
Keyword(s):  
Grain Boundaries ◽  
High Temperatures ◽  
Electron Backscatter Diffraction ◽  
Copper Wire ◽  
High Mobility ◽  
Energy Difference ◽  
Twin Boundaries ◽  
Electron Backscatter ◽  
Backscatter Diffraction

AbstractThe microstructural evolution of a cold drawn copper wire (reduction area of 38%) during primary recrystallization and grain growth was observed in situ by electron backscatter diffraction. Two thermal treatments were performed, and successive scans were acquired on samples undergoing heating from ambient temperature to a steady state of 200°C or 215°C. During a third in situ annealing, the temperature was continuously increased up to 600°C. Nuclei were observed to grow at the expense of the deformed microstructure. This growth was enhanced by the high stored energy difference between the nuclei and their neighbors (driving energy in recrystallization) and by the presence of high-angle grain boundaries of high mobility. In the early stages of growth, the nuclei twin and the newly created orientations continue to grow to the detriment of the strained copper. At high temperatures, the disappearance of some twins was evidenced by the migration of the incoherent twin boundaries. Thermal grooving of grain boundaries is observed at these high temperatures and affects the high mobile boundaries but tends to preserve the twin boundaries of lower energy. Thus, grooving may contribute to the twin vanishing.

Characterization of Sputtered CdTe Thin Films with Electron Backscatter Diffraction and Correlation with Device Performance

2015 ◽  
Vol 21 (4) ◽  
pp. 927-935 ◽  
Author(s):  
Matthew M. Nowell ◽  
Michael A. Scarpulla ◽  
Naba R. Paudel ◽  
Kristopher A. Wieland ◽  
Alvin D. Compaan ◽  
...  
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Electron Backscatter Diffraction ◽  
Electrical Performance ◽  
Poor Correlation ◽  
Twin Boundaries ◽  
Electron Backscatter ◽  
Backscatter Diffraction

AbstractThe performance of polycrystalline CdTe photovoltaic thin films is expected to depend on the grain boundary density and corresponding grain size of the film microstructure. However, the electrical performance of grain boundaries within these films is not well understood, and can be beneficial, harmful, or neutral in terms of film performance. Electron backscatter diffraction has been used to characterize the grain size, grain boundary structure, and crystallographic texture of sputtered CdTe at varying deposition pressures before and after CdCl2 treatment in order to correlate performance with microstructure. Weak fiber textures were observed in the as-deposited films, with (111) textures present at lower deposition pressures and (110) textures observed at higher deposition pressures. The CdCl2-treated samples exhibited significant grain recrystallization with a high fraction of twin boundaries. Good correlation of solar cell efficiency was observed with twin-corrected grain size while poor correlation was found if the twin boundaries were considered as grain boundaries in the grain size determination. This implies that the twin boundaries are neutral with respect to recombination and carrier transport.

scholarly journals Pop-in behavior and elastic-to-plastic transition of polycrystalline pure iron during sharp nanoindentation

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Fabian Pöhl
Keyword(s):  
Grain Boundaries ◽  
Strong Influence ◽  
Electron Backscatter Diffraction ◽  
Dislocation Nucleation ◽  
Stress Fields ◽  
Shear Stresses ◽  
Statistical Process ◽  
Iron Crystal ◽  
Electron Backscatter ◽  
Backscatter Diffraction

Abstract This study analyzes the elastic-to-plastic transition during nanoindentation of polycrystalline iron. We conduct nanoindentation (Berkovich indenter) experiments and electron backscatter diffraction analysis to investigate the initiation of plasticity by the appearance of the pop-in phenomenon in the loading curves. Numerous load–displacement curves are statistically analyzed to identify the occurrence of pop-ins. A first pop-in can result from plasticity initiation caused by homogeneous dislocation nucleation and requires shear stresses in the range of the theoretical strength of a defect-free iron crystal. The results also show that plasticity initiation in volumes with preexisting dislocations is significantly affected by small amounts of interstitially dissolved atoms (such as carbon) that are segregated into the stress fields of dislocations, impeding their mobility. Another strong influence on the pop-in behavior is grain boundaries, which can lead to large pop-ins at relatively high indentation loads. The pop-in behavior appears to be a statistical process affected by interstitial atoms, dislocation density, grain boundaries, and surface roughness. No effect of the crystallographic orientation on the pop-in behavior can be observed.

scholarly journals Novel −75°C SEM cooling stage: application for martensitic transformation in steel

Microscopy ◽  
2020 ◽  
Author(s):  
Kaneaki Tsuzazki ◽  
Motomichi Koyama ◽  
Ryosuke Sasaki ◽  
Keiichiro Nakafuji ◽  
Kazushi Oie ◽  
...  
Keyword(s):  
Martensitic Transformation ◽  
Electron Backscatter Diffraction ◽  
Dislocation Slip ◽  
In Situ Observation ◽  
Contrast Imaging ◽  
Cooling Stage ◽  
Electron Channelling ◽  
Electron Backscatter ◽  
Backscatter Diffraction

Abstract Microstructural changes during the martensitic transformation from face-centred cubic (FCC) to body-centred cubic (BCC) in an Fe-31Ni alloy were observed by scanning electron microscopy (SEM) with a newly developed Peltier stage available at temperatures to  −75°C. Electron channelling contrast imaging (ECCI) was utilized for the in situ observation during cooling. Electron backscatter diffraction analysis at ambient temperature (20°C) after the transformation was performed for the crystallographic characterization. A uniform dislocation slip in the FCC matrix associated with the transformation was detected at −57°C. Gradual growth of a BCC martensite was recognized upon cooling from −57°C to −63°C.

scholarly journals Coupling Automated Electron Backscatter Diffraction with Transmission Electron and Atomic Force Microscopies

2000 ◽  
Vol 6 (S2) ◽  
pp. 940-941
Author(s):  
A.J. Schwartz ◽  
M. Kumar ◽  
P.J. Bedrossian ◽  
W.E. King
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Thermomechanical Processing ◽  
Electron Backscatter Diffraction ◽  
Grain Boundary Character Distribution ◽  
Atomic Force ◽  
Transmission Electron ◽  
Electron Backscatter ◽  
Network Engineering ◽  
Backscatter Diffraction

Grain boundary network engineering is an emerging field that encompasses the concept that modifications to conventional thermomechanical processing can result in improved properties through the disruption of the random grain boundary network. Various researchers have reported a correlation between the grain boundary character distribution (defined as the fractions of “special” and “random” grain boundaries) and dramatic improvements in properties such as corrosion and stress corrosion cracking, creep, etc. While much early work in the field emphasized property improvements, the opportunity now exists to elucidate the underlying materials science of grain boundary network engineering. Recent investigations at LLNL have coupled automated electron backscatter diffraction (EBSD) with transmission electron microscopy (TEM)5 and atomic force microscopy (AFM) to elucidate these fundamental mechanisms.An example of the coupling of TEM and EBSD is given in Figures 1-3. The EBSD image in Figure 1 reveals “segmentation” of boundaries from special to random and random to special and low angle grain boundaries in some grains, but not others, resulting from the 15% compression of an Inconel 600 polycrystal.

scholarly journals Effect of TiO2-Nanoparticles on Ni Electrodeposition on Copper Wire

Metals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 406
Author(s):  
Samiha Saad ◽  
Zakaria Boumerzoug ◽  
Anne Laure Helbert ◽  
François Brisset ◽  
Thierry Baudin
Keyword(s):  
Surface Morphology ◽  
Tio2 Nanoparticles ◽  
Vickers Microhardness ◽  
Electron Backscatter Diffraction ◽  
Copper Wire ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electron Backscatter ◽  
Electrodeposited Nickel ◽  
Backscatter Diffraction

The objective of this work is to study, on a copper wire, the effect of TiO2-nanoparticles on electrodeposited nickel. Both the microstructure and surface morphology (texture) of the coating were investigated. This deposit is obtained from baths of sulfated electroplating Watts. The Ni-TO2 composite coating is deposited at a temperature of 45 °C. The composite deposit is prepared by adding nanoparticles of TiO2 to the electrolyte. The characterization has been carried out by X-ray diffraction, scanning electron microscopy, microhardness measurements, and electron backscatter diffraction (EBSD). Vickers microhardness was used to characterize the mechanical properties of the electrodeposited nickel. The results showed the effects of the TiO2 on the composition, the surface morphology, and the hardness of the deposited layer. However, there was not an effect of TiO2 nanoparticles on texture.

In-situ Recrystallization Experiments Using Electron Backscatter Diffraction

2007 ◽  
Vol 13 (S02) ◽  
Author(s):  
D Prior ◽  
M Bestmann ◽  
S Piazolo ◽  
NC Seaton ◽  
DJ Tatham ◽  
...  
Keyword(s):  
Electron Backscatter Diffraction ◽  
Electron Backscatter ◽  
Backscatter Diffraction

scholarly journals Electron backscatter diffraction study of orientation gradients at the grain boundaries of a polycrystalline steel sheet deformed along different loading paths

2017 ◽  
Vol 50 (4) ◽  
pp. 1179-1191 ◽  
Author(s):  
J. W. Signorelli ◽  
A. Roatta ◽  
N. De Vincentis ◽  
C. Schwindt ◽  
M. Avalos ◽  
...  
Keyword(s):  
Grain Boundaries ◽  
Steel Sheet ◽  
Electron Backscatter Diffraction ◽  
Effective Thickness ◽  
Local Orientation ◽  
Orientation Gradient ◽  
Loading Paths ◽  
Electron Backscatter ◽  
Backscatter Diffraction ◽  
Local Misorientation

In a polycrystal, the heterogeneity of plastic deformation in a particular grain is greatly enhanced by adjacent grains that constrain the grain's local behavior, often imposing orientation gradients. This work aims to characterize and quantify the local orientation gradients near grain boundaries (GBs). Electron backscatter diffraction (EBSD) measurements were made on a 0.67 mm thick aluminium-killed drawing quality (AKDQ) steel sheet subjected to different loading paths that are typical of forming operations. A statistical analysis shows that a considerable fraction of the analyzed GB profiles can be described by an orientation profile with a constant slope near the GB. In order to quantify this behavior, as well as the degree of localization, two new parameters, based on the local orientation gradient assessed by EBSD, are proposed: BET (boundary effective thickness) and GAS (gradient average severity). These parameters should be considered together, the BET as an effective thickness of the GB zone where the orientation gradient takes place and the GAS as a measure of the magnitude or severity of the orientation gradient. Additionally, the GAS parameter shows a strong correlation with the accumulated macroscopic strain for the investigated deformation levels and loading paths, while the BET profile clearly reveals the influence of the GB on the misorientation profiles. Tension and biaxial stretching results lead to a BET value between 1.5 and 2 µm. Finally, it is shown that the local misorientation in the GB zone, on both sides of the GB line, is disperse and it does not correlate simply with misorientation or even the slip-transfer geometry across the GB. Moreover, the observed average local misorientation dispersions in GB zones are different for each loading condition.

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