scholarly journals Direct Visualization of Grain Boundaries in Quartzites using Atomic Force Microscopy: Application to Study of Fluid Percolation in Continental Crust

2021 ◽  
Author(s):  
Ritabrata Dobe ◽  
Anuja Das ◽  
Rabibrata Mukherjee ◽  
Saibal Gupta
Keyword(s):  
Atomic Force Microscopy ◽  
Grain Boundary ◽  
Continental Crust ◽  
Electron Backscatter Diffraction ◽  
Vital Role ◽  
Force Microscopy ◽  
Atomic Force ◽  
Width Measurements ◽  
Lower Temperature ◽  
Backscatter Diffraction

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.

scholarly journals Evaluation of grain boundaries as percolation pathways in quartz-rich continental crust using Atomic Force Microscopy

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ritabrata Dobe ◽  
Anuja Das ◽  
Rabibrata Mukherjee ◽  
Saibal Gupta
Keyword(s):  
Atomic Force Microscopy ◽  
Grain Boundary ◽  
Continental Crust ◽  
Electron Backscatter Diffraction ◽  
Vital Role ◽  
Force Microscopy ◽  
Atomic Force ◽  
Width Measurements ◽  
Lower Temperature ◽  
Backscatter Diffraction

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.

scholarly journals A thermal grooving study of relative grain boundary energies of nickel in polycrystalline Ni and in a Ni/YSZ anode measured by atomic force microscopy

2021 ◽  
pp. 116936
Author(s):  
Patricia Haremski ◽  
Lars Epple ◽  
Matthias Wieler ◽  
Piero Lupetin ◽  
Richard Thelen ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Grain Boundary ◽  
Force Microscopy ◽  
Atomic Force

Growth of 4H-SiC Single Crystals on 6H-SiC Seeds with an Open Backside by PVT Method

2009 ◽  
Vol 615-617 ◽  
pp. 15-18 ◽  
Author(s):  
Emil Tymicki ◽  
Krzysztof Grasza ◽  
Katarzyna Racka ◽  
Marcin Raczkiewicz ◽  
Tadeusz Łukasiewicz ◽  
...  
Keyword(s):  
Single Crystals ◽  
Electron Backscatter Diffraction ◽  
Structural Defects ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Optical Scanning ◽  
Atomic Force ◽  
The Stability ◽  
Backscatter Diffraction ◽  
Source Materials

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.

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.

Interrogation of Alumina Grain Boundaries using Atomic Force Microscopy

1999 ◽  
Vol 580 ◽  
Author(s):  
P.A. Tibble ◽  
B.R. Heywood ◽  
R. Richardson ◽  
P. Barnes
Keyword(s):  
Particle Size ◽  
Atomic Force Microscopy ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Preferential Growth ◽  
Polycrystalline Alumina ◽  
Present Evidence ◽  
Force Microscopy ◽  
Atomic Force ◽  
Uniform Growth

AbstractA number of MgO doped (3wt%) polycrystalline alumina samples were prepared. The preparation of these samples varied; different regimes for annealing (1500 – 1600°C) and a range of dwell times were examined. Atomic force microscopy (AFM) was used to study surface features. Information on grain boundary dimensions (depth, width) is presented along with a study of grain particle size. The growth of the grain boundaries was found to contradict Mullins' theory of uniform growth with time. We also present evidence for Ostwalds' ripening and the preferential growth of [001] oriented grains.

Investigation of Surface Grooves from Migrating Grain Boundaries

2002 ◽  
Vol 750 ◽  
Author(s):  
Nicole E. Munoz ◽  
Shelley R. Gilliss ◽  
N. Ravishankar ◽  
C. Barry Carter
Keyword(s):  
Atomic Force Microscopy ◽  
Grain Boundary ◽  
Light Microscopy ◽  
Grain Boundaries ◽  
High Purity ◽  
Moving Boundary ◽  
Migration Process ◽  
Force Microscopy ◽  
Atomic Force ◽  
And Migration

ABSTRACTVisible-light microscopy (VLM) and atomic-force microscopy (AFM) were used to study the progression of grain-boundary grooving and migration in high-purity alumina (Lucalox™). Groove profiles from the same grain boundaries were revisited using AFM following successive heat-treatments. The grooves measured from migrating grain boundaries were found to have asymmetric partial-angles compared to those measured from boundaries that did not migrate during the experiment. For a moving boundary, the grain with the larger partial-angle was consistently found to grow into the grain with the smaller partial-angle. Migrating boundaries were observed to leave behind remnant thermal grooves. The observations indicate that the boundary may be bowing out during the migration process.

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