Electron backscatter diffraction analysis of Pb(Mg1/3Nb2/3)O3–35mol%PbTiO3 single crystals grown by seeded polycrystal conversion

2001 ◽  
Vol 16 (3) ◽  
pp. 694-700 ◽  
Author(s):  
Ajmal Khan ◽  
Derrick T. Carpenter ◽  
Adam M. Scotch ◽  
Helen M. Chan ◽  
Martin P. Harmer
Keyword(s):  
Single Crystal ◽  
Single Crystals ◽  
Electron Backscatter Diffraction ◽  
Second Phase ◽  
Crystal Imperfections ◽  
Simple Boundary ◽  
Electron Backscatter ◽  
Backscatter Diffraction ◽  
Crystal Seed ◽  
Grown Single Crystal

Electron backscatter diffraction (EBSD) has been applied to characterize Pb(Mg1/3Nb2/3)O3–35 mol%PbTiO3 single crystals grown by the seeded polycrystal conversion method. Macroscopically triangular crystal growth fronts were shown to each be associated with discrete crystals that originated from slightly misoriented segments of an initially cracked single-crystal seed plate. Various types of crystal imperfections, including voids, second-phase regions, and polycrystalline matrix grains trapped within the grown region, were readily identified and distinguished from one another using EBSD. Further, it was shown that trapped matrix grains in the grown region had consistently small misorientations with respect to the grown single crystal and this may be qualitatively explained by a simple boundary energetics argument. The significance of the trapped grains is discussed.

scholarly journals A New Electron Backscatter Diffraction-Based Method to Study the Role of Crystallographic Orientation in Ductile Damage Initiation

Metals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 113
Author(s):  
Behnam Shakerifard ◽  
Jesus Galan Lopez ◽  
Leo A. I. Kestens
Keyword(s):  
Crystallographic Orientation ◽  
Electron Backscatter Diffraction ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Second Phase ◽  
Post Mortem ◽  
Bainitic Steel ◽  
Damage Initiation ◽  
Electron Backscatter ◽  
Backscatter Diffraction

The third generation of advanced high strength steels shows promising properties for automotive applications. The macroscopic mechanical response of this generation can be further improved by a better understanding of failure mechanisms on the microstructural level and micro-mechanical behavior under various loading conditions. In the current study, the microstructure of a multiphase low silicon bainitic steel is characterized with a scanning electron microscope (SEM) equipped with an electron backscatter diffraction detector. A uniaxial tensile test is carried out on the bainitic steel with martensite and carbides as second phase constituents. An extensive image processing on SEM micrographs is conducted in order to quantify the void evolution during plastic deformation. Later, a new post-mortem electron backscatter diffraction-based method is introduced to address the correlation between crystallographic orientation and damage initiation. In this multiphase steel, particular crystallographic orientation components were observed to be highly susceptible to micro-void formation. It is shown that stress concentration around voids is rather relaxed by void growth than local plasticity. Therefore, this post-mortem method can be used as a validation tool together with a crystal plasticity-based hardening model in order to predict the susceptible crystallographic orientations to damage nucleation.

A remark on ab initio indexing of electron backscatter diffraction patterns

2021 ◽  
Vol 54 (6) ◽  
Author(s):  
Adam Morawiec
Keyword(s):  
Single Crystal ◽  
Ab Initio ◽  
Diffraction Data ◽  
Electron Backscatter Diffraction ◽  
Single Crystal Diffraction ◽  
X Ray ◽  
Electron Backscatter ◽  
Diffraction Patterns ◽  
Backscatter Diffraction

There is a growing interest in ab initio indexing of electron backscatter diffraction (EBSD) patterns. The methods of solving the problem are presented as innovative. The purpose of this note is to point out that ab initio EBSD indexing belongs to the field of indexing single-crystal diffraction data, and it is solved on the same principles as indexing of patterns of other types. It is shown that reasonably accurate EBSD-based data can be indexed by programs designed for X-ray data.

The Crystallography of Pyrite Framboids

2021 ◽  
pp. 110-128
Author(s):  
David Rickard
Keyword(s):  
Single Crystal ◽  
Driving Force ◽  
Structural Control ◽  
Electron Backscatter Diffraction ◽  
X Ray Diffraction ◽  
Entropy Maximization ◽  
Self Organized ◽  
Electron Backscatter ◽  
Ordered Array ◽  
Backscatter Diffraction

Single crystal X-ray diffraction analyses of even the most perfectly organized framboids show ring patterns indicative of randomly oriented particles. Therefore, framboids are not mesocrystals or extreme skeletal varieties of single crystals. Electron backscatter diffraction shows that the microcrystals within a framboid are not crystallographically aligned. Around half of the microcrystals in organized framboids have crystallographic orientations rotated 90º. The results of single crystal XRD and framboid EBSD studies clearly show that the microcrystals are self-organized rather than being the result of a crystallographic template or preexisting structural control. The pre-formed framboid microcrystals which are initially randomly organized throughout the framboid volume then, in some cases, begin to wholly or partly self-order. This is effected by rotation of the microcrystals until an ordered array is produced. The consequence of this rotation must be that the microcrystals are initially packed loosely enough for rotation to occur. The processes involved in the rotation could include forces intrinsic to the microcrystals themselves, such as surface forces, or forces imposed from outside the framboid, such as Brownian motion. The fundamental driving force for microcrystal rotation and the development of organized microcrystal arrays in framboids is entropy maximization.

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