Inherited Fabric in an Omphacite Symplectite: Reconstruction of Plastic Deformation under Ultra-High Pressure Conditions

2013 ◽  
Vol 19 (4) ◽  
pp. 942-949 ◽  
Author(s):  
Florian Heidelbach ◽  
Michael P. Terry
Keyword(s):  
Orientation Relationship ◽  
Electron Backscatter Diffraction ◽  
Pure Shear ◽  
Additional Component ◽  
Western Gneiss Region ◽  
Crystallographic Preferred Orientation ◽  
Ultra High Pressure ◽  
Shear Component ◽  
Electron Backscatter ◽  
Backscatter Diffraction

AbstractWe investigated an eclogitic gneiss from the Western Gneiss Region in Norway, which underwent subduction as part of Baltica lithosphere beneath Laurentia during the Scandian orogeny. Petrologic data indicate that the eclogite was deformed plastically at about 4 GPa and 800°C producing a strong macroscopic foliation and lineation. Whereas garnet remained largely stable during the retrograde uplift, omphacite was transformed statically into a symplectite consisting of lamellar diopside and plagioclase with more equant grains of hornblende and orthopyroxene. Measurements of the crystallographic preferred orientation with electron backscatter diffraction show that diopside and hornblende, as well as orthopyroxene, have a systematic orientation relationship with the macroscopic fabric, as well as the (presumed) orientation of the host omphacite. The orientation relationship between the chain silicates is very sharp with the crystallographic forms {100}, {010}, and ⟨001⟩ being parallel. Their bulk texture shows a maximum of ⟨001⟩ parallel to the lineation and girdles of {010} and {110} perpendicular to the lineation with maxima subparallel to the foliation corresponding to an L-type texture of the original omphacite and indicating constrictional strain with an additional component of pure shear/simple shear component.

Crystallographic orientation of ilmenite inclusions in amphibole – an electron backscatter diffraction study

2020 ◽  
Vol 235 (4-5) ◽  
pp. 105-116
Author(s):  
Chang Xu ◽  
Shanrong Zhao ◽  
Jiaohua Zhou ◽  
Xu He ◽  
Haijun Xu
Keyword(s):  
Crystallographic Orientation ◽  
Electron Backscatter Diffraction ◽  
Reduction Reaction ◽  
Formation Temperature ◽  
Orientation Relationships ◽  
Ultra High Pressure ◽  
Electron Backscatter ◽  
Metamorphic Terrane ◽  
Backscatter Diffraction ◽  
Group 1

AbstractOrientated ilmenite inclusions have been discovered in amphibole of hornblendite from the Zhujiapu area, Dabie ultra-high-pressure (UHP) metamorphic terrane, China. In order to characterize the crystallographic orientation relationships between ilmenite inclusions and amphibole host and reconstruct the mechanism of their formation, we present an electron backscatter diffraction (EBSD) analysis combined with energy dispersive spectroscopy (EDS) analysis and electron microprobe analysis (EPMA) for ilmenite inclusions and amphibole host. The inclusions can be subdivided into four groups: (1) 60.2% of ilmenites have the crystallographic orientation {0001}Ilm // {100}Amp, (101̅0)Ilm // {010}Amp, [112̅0]Ilm // <001> Amp and [112̅0]Ilm // <012 > Amp. (2) 16.5% of ilmenites have <0001> Ilm // <001> Amp, (101̅0)Ilm // {010}Amp, (112̅0)Ilm // {100}Amp and [3̅031]Ilm // <012> Amp. (3) 13.8% of ilmenites have <0001> Ilm // <012> Amp, (112̅0)Ilm // {100}Amp and [3̅031]Ilm // <001> Amp. (4) 9.5% of ilmenites have <0001> Ilm // [1̅12]Amp, (101̅0)Ilm // {201}Amp, [112̅0]Ilm // [1̅12]Amp and ${[11\overline {21} ]_{Ilm}}$// <010> Amp. By comparing the lattice relationship between ilmenite inclusions and amphibole hosts, it is shown that the frequency of the ilmenite inclusions in different groups is related to the lattice coherency and oxygen packing. Group-1 of the ilmenite inclusions was most likely be formed via a solid-state exsolution process by cooling of the hornblendite after the intrusion was emplaced. The other three groups of ilmenite inclusions were probably formed via reduction reaction in an open system. The formation temperature of the ilmenite inclusions is estimated by using the TiO2 solubility geothermeter in amphibole. The minimum formation temperature of the ilmenite inclusions is about 1025 °C, and the maximum formation temperature of the ilmenite inclusions is about 1126 °C.

Orientation Correlation during α→β Up-Transformation Induced by Electric Current Pulses in a Cu-Zn Alloy

2014 ◽  
Vol 783-786 ◽  
pp. 2406-2409
Author(s):  
Xiang Zhao ◽  
Xin Li Wang ◽  
Dong Xue Li ◽  
Wen Bin Dai
Keyword(s):  
Electric Current ◽  
Orientation Relationship ◽  
Electron Backscatter Diffraction ◽  
Current Pulses ◽  
Α Phase ◽  
Electric Current Pulses ◽  
Electron Backscatter ◽  
Backscatter Diffraction ◽  
The Relationship ◽  
Zn Alloy

In this work, the orientation of the β variants within a single parent α grain on the α→β up-transformation induced by electric current pulses in a Cu-Zn alloy was investigated. Electron backscatter diffraction (EBSD) was used to determine the relationship between the α phase and the β variants. By EBSD analysis, it was found that crystallographic variant selection was observed not only across those prior α/α grain boundaries, but also within the α grain interior. Results revealed that the orientation relationship between the α phase and the β associated with nucleation from α phase was close to the Kurdjumov-Sachs (K-S) orientation relationship, which better described the orientation relationship for α nucleation within β grains.

Orientation relationships between α-zirconium and δ-hydride within a hydride blister

2017 ◽  
Vol 50 (2) ◽  
pp. 349-356 ◽  
Author(s):  
David Kerr ◽  
Fei Long ◽  
Gladys Domizzi ◽  
Mark R. Daymond
Keyword(s):  
Orientation Relationship ◽  
Electron Backscatter Diffraction ◽  
Zirconium Alloys ◽  
Experimental Methods ◽  
Grain Structure ◽  
Orientation Relationships ◽  
Orientation Maps ◽  
Electron Backscatter ◽  
Backscatter Diffraction

Both the expected and an additional orientation relationship between α-Zr and δ-hydride in blistered zirconium alloys are explored through the reconstruction of the parent α-Zr phase from electron backscatter diffraction maps of δ-hydride. Parent and child variant relationships for the transformation are presented with the aim of reconstruction of the parent α-Zr grain structure and texture from orientation maps of the δ-hydride at varying distances from the blister centre in a recrystallized Zircaloy-4 sample. Up to 13% of the δ-hydride is found to be variants of the additional orientation relationship, the fraction of which decreases with increasing distance from the blister centre. Texture reconstructions by other experimental methods are accordingly suggested to incorporate the additional orientation relationship.

Determination of the orientation relationship between austenite and 5M modulated martensite in Ni–Mn–Ga alloys

2011 ◽  
Vol 44 (6) ◽  
pp. 1222-1226 ◽  
Author(s):  
Zongbin Li ◽  
Yudong Zhang ◽  
Claude Esling ◽  
Xiang Zhao ◽  
Liang Zuo
Keyword(s):  
Orientation Relationship ◽  
Room Temperature ◽  
Electron Backscatter Diffraction ◽  
Residual Austenite ◽  
Orientation Data ◽  
Correct Orientation ◽  
Electron Backscatter ◽  
Crystallographic Characteristics ◽  
Backscatter Diffraction

The microstructural and crystallographic characteristics of 5M martensite in an Ni50Mn28Ga22alloy were investigated by electron backscatter diffraction (EBSD) analysis. The microstructure of 5M martensite observed at room temperature can be characterized by broad plates with alternately distributed fine lamellae (variants). With the accurate EBSD orientation measurements and by application of monoclinic superstructure information, four twin-related variants in one broad plate were identified. On the basis of the correct orientation data of martensite variants acquired from the EBSD measurements, the more favourable orientation relationship between austenite and 5M martensite was revealed to be the Pitsch relation with (101)A//(1 {\overline 2} \hskip1{\overline 5})5Mand [10 {\overline 1}]A//[{\overline 5} \hskip1 {\overline 5} 1]5Mby detailed crystallographic calculation without residual austenite.

scholarly journals Electron backscatter diffraction (EBSD) based determination of crystallographic preferred orientation (CPO) in warm, coarse-grained ice: a case study, Storglaciären, Sweden

2020 ◽  
Author(s):  
Morgan E. Monz ◽  
Peter J. Hudleston ◽  
David J. Prior ◽  
Zachary Michels ◽  
Sheng Fan ◽  
...  
Keyword(s):  
Electron Backscatter Diffraction ◽  
Shear Plane ◽  
Preferred Orientation ◽  
Coarse Grained ◽  
Strain History ◽  
Shear Direction ◽  
Preparation Technique ◽  
Crystallographic Preferred Orientation ◽  
Electron Backscatter ◽  
Backscatter Diffraction

Abstract. Microstructures provide key insights into understanding the mechanical behavior of ice. Crystallographic preferred orientation (CPO) develops during plastic deformation as ice dynamically recrystallizes, with the dominance of intracrystalline glide on the basal plane. CPO patterns in fine-grained ice have been relatively well characterized and understood in experiments and nature, whereas CPO patterns in "warm" (T > −10 ºC), coarse-grained, natural ice remain enigmatic. Previous microstructural studies of coarse-grained ice have been limited to c-axis orientations using light optical measurements. We have developed a new sample preparation technique, by constructing composite sections, to allow us to use electron backscatter diffraction (EBSD) to obtain a representative, bulk CPO on coarse-grained ice. We suggest that a grain sampling bias of large, branching crystals that appear multiple times as island grains in thin section may result in the typical multiple maxima CPOs previously identified in warm, coarse-grained ice that has been subjected to prolonged shear. CPOs combined from multiple samples of highly sheared ice from Storglaciären provide a more comprehensive picture of the microstructure and yield a pronounced cluster of c-axes sub-normal to the shear plane and elongate or split in a plane normal to the shear direction, and a concomitant girdle of a-axes parallel to the shear plane with a maximum perpendicular to the shear direction. This pattern compares well with patterns produced by sub-sampling data sets from experimentally sheared ice at high homologous temperatures up to strains of ~ 1.5. Shear strains in the margin of Storglaciären are much higher than those in experimental work. At much lower natural strain rates, dynamic recrystallization, particularly grain boundary migration, may have been more effective so that the CPO has been continuously reset and represents a smaller, final fraction of the shear history, rather than the entire finite strain history.

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