Combined EBSD and AFM Study of the Corrosion Behaviour of ETP-Cu

2011 ◽  
Vol 702-703 ◽  
pp. 673-676 ◽  
Author(s):  
Linsey Lapeire ◽  
Esther Martinez Lombardia ◽  
Kim Verbeken ◽  
Iris de Graeve ◽  
Leo Kestens ◽  
...  

In order to increase the sustainability of metals, a more detailed understanding of the corrosion process is of crucial importance. Current literature often considers corrosion as a purely chemical interaction with a nearly exclusive dependence on compositional effects, while ignoring microstructural and crystallographic properties of the metal surface. Some recent literature data, however, suggest an important effect of microstructural elements such as grain size, crystallographic orientation and grain boundary characteristics. The aim of this work is to obtain a better understanding of the relation between the corrosion behaviour of a metal and its microstructural and crystallographic features. Therefore, warm rolled Electrolytic Tough Pitch (ETP-) Cu was immersed in a 0.1 M NaCl and 0.5M Na2SO4 solution and the combination of Atomic Force Microscope (AFM) and Electron Backscatter Diffraction (EBSD) allowed to identify differences in attack for different crystallographic orientations.

2007 ◽  
Vol 558-559 ◽  
pp. 873-878 ◽  
Author(s):  
Dorothée Dorner ◽  
Yoshitaka Adachi ◽  
Kaneaki Tsuzaki

Compression tests were performed on Fe-3%Si specimens with few grains. The deformation microstructure and microtexture were investigated by electron backscatter diffraction (EBSD) and related to the initial crystal orientation and grain boundary characteristics. Groups of microbands were found that are characterised by a periodic change in crystal orientation, shear at the grain boundary, and the formation of new grains. It is supposed that these microband groups represent an early stage of microshear band development.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ritabrata Dobe ◽  
Anuja Das ◽  
Rabibrata Mukherjee ◽  
Saibal Gupta

AbstractHydrous fluids play a vital role in the chemical and rheological evolution of ductile, quartz-bearing continental crust, where fluid percolation pathways are controlled by grain boundary domains. In this study, widths of grain boundary domains in seven quartzite samples metamorphosed under varying crustal conditions were investigated using Atomic Force Microscopy (AFM) which allows comparatively easy, high magnification imaging and precise width measurements. It is observed that dynamic recrystallization at higher metamorphic grades is much more efficient at reducing grain boundary widths than at lower temperature conditions. The concept of force-distance spectroscopy, applied to geological samples for the first time, allows qualitative estimation of variations in the strength of grain boundary domains. The strength of grain boundary domains is inferred to be higher in the high grade quartzites, which is supported by Kernel Average Misorientation (KAM) studies using Electron Backscatter Diffraction (EBSD). The results of the study show that quartzites deformed and metamorphosed at higher grades have narrower channels without pores and an abundance of periodically arranged bridges oriented at right angles to the length of the boundary. We conclude that grain boundary domains in quartz-rich rocks are more resistant to fluid percolation in the granulite rather than the greenschist facies.


2009 ◽  
Vol 615-617 ◽  
pp. 15-18 ◽  
Author(s):  
Emil Tymicki ◽  
Krzysztof Grasza ◽  
Katarzyna Racka ◽  
Marcin Raczkiewicz ◽  
Tadeusz Łukasiewicz ◽  
...  

4H-SiC single crystals grown by the seeded physical vapour transport method have been investigated. These crystals were grown on 6H-SiC seeds. The influence of the seed temperature, form and granulation of SiC source materials on the stability and efficiency of the 4H polytype growth have been investigated. A new way of the seed mounting - with an open backside - has been used. Crystals obtained were free of structural defects in the form of hexagonal voids. The crystalline structure of SiC crystals was investigated by EBSD (Electron Backscatter Diffraction) and X-Ray diffraction methods. Moreover, defects in crystals and wafers cut from these crystals were examined by optical, scanning electron and atomic force microscopy combined with KOH etching.


2000 ◽  
Vol 6 (S2) ◽  
pp. 940-941
Author(s):  
A.J. Schwartz ◽  
M. Kumar ◽  
P.J. Bedrossian ◽  
W.E. King

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.


Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 236
Author(s):  
Yao Lin ◽  
Shan Liu ◽  
Tao Wu ◽  
Guangchun Wang

The “torsion and annealing” grain boundary modification of pure nickel wires with different diameters was carried out in this paper. The effects of torsional cycles as well as unidirectional/bidirectional torsion methods on grain boundary characteristic distribution and plasticity were investigated. The fraction of special boundaries, grain boundary characteristic distributions and grain orientations of samples with different torsion parameters were detected by electron backscatter diffraction. Hardness measurement was conducted to characterize the plasticity. Then, the relationship between micro grain boundary characteristics and macro plasticity was explored. It was found that the special boundaries, especially Σ3 boundaries, are increased after torsion and annealing and effectively broke the random boundary network. The bidirectional torsion with small torsional circulation unit was the most conducive way to improve the fraction of special boundaries. The experiments also showed that there was a good linear correlation between the fraction of special boundaries and hardness. The plasticization mechanism was that plenty of grains with Σ3 boundaries, [001] orientations and small Taylor factor were generated in the thermomechanical processes. Meanwhile, the special boundaries broke the random boundary network. Therefore, the material was able to achieve greater plastic deformation. Moreover, the mechanism of torsion and annealing on the plasticity of pure nickel was illustrated, which provides theoretical guidance for the pre-plasticization of nickel workpieces.


2021 ◽  
Author(s):  
Ritabrata Dobe ◽  
Anuja Das ◽  
Rabibrata Mukherjee ◽  
Saibal Gupta

Abstract Hydrous fluids play a vital role in the chemical and rheological evolution of ductile, quartz-bearing continental crust, where fluid percolation pathways are controlled by grain boundary domains. In this study, widths of grain boundary domains in seven quartzite samples metamorphosed under varying crustal conditions were investigated using Atomic Force Microscopy (AFM) which allows comparatively easy, high magnification imaging and precise width measurements. It is observed that dynamic recrystallization at higher metamorphic grades is much more efficient at reducing grain boundary widths than at lower temperature conditions. The concept of force-distance spectroscopy, applied to geological samples for the first time, allows qualitative estimation of variations in the strength of grain boundary domains. The strength of grain boundary domains is inferred to be higher in the high grade quartzites, which is supported by Kernel Average Misorientation (KAM) studies using Electron Backscatter Diffraction (EBSD). The results of the study show that quartzites deformed and metamorphosed at higher grades have narrower channels without pores and an abundance of periodically arranged bridges oriented at right angles to the length of the boundary. We conclude that grain boundary domains in quartz-rich rocks are more resistant to fluid percolation in the granulite rather than the greenschist facies.


2011 ◽  
Vol 415-417 ◽  
pp. 901-906
Author(s):  
Xiang Yan ◽  
Fu Xing Yin ◽  
Gui Feng Zhou ◽  
W. Chen

The grain and grain boundary characteristics of HSLA100 steel quenched in the 2-phase region were investigated by electron backscatter diffraction (EBSD).The results showed that the austenite amount was controlled by the 2-phase region heating temperature and the composition and morphology of transformation products were mostly depended on the carbon content in austenite. With the quenching temperature in 2-phase region increasing, the dislocation density in bainite decrease as a result of the block bainite coarsening and mergering, which makes the subgrains with much more low angle grain boundaries (2°~15°) decreasing and the massive ferrite with more high angle grain boundaries increasing gradually. Furthermore, the lath martensite or bainite with high angle grain boundaries and subgrains with low angle grain boundaries gradually increase owing to new austenite grain increasing and growing up. With the roles of above two interactions, some EBSD characteristics such as the packet size and the number fraction of high angle grain boundaries all have a peak present at 740°C


2007 ◽  
Vol 1012 ◽  
Author(s):  
Helio Moutinho ◽  
Ramesh Dhere ◽  
Chun-Sheng Jiang ◽  
Bobby To ◽  
Mowafak Al-Jassim

AbstractIn electron-backscatter diffraction, crystalline orientation maps are formed while the electron beam of an SEM scans the sample surface. EBSD requires a flat sample to avoid shadowing of the electrons from the detector by surface features. In this work, we investigate the preparation of CdTe samples deposited by close-spaced sublimation for EBSD analysis. Untreated samples were rough, resulting in areas with no EBSD signal. We processed the samples by polishing and ion-beam milling. Polishing produced flat samples, but low-quality EBDS data, because the top surface of the samples had poor crystallinity. In contrast, ion-beam milling proved to be suitable for producing flat samples with minimal surface damage, yielding good EBSD data. We also analyzed the samples with atomic force microscopy, and correlated the quality of the EBSD data with sample roughness. The EBSD data showed that the CdTe films were randomly oriented and had columnar growth and a high density of <111> twin boundaries.


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