Grain Boundary Structure and Structure-Behavior Relationships in HCP Metals

1991 ◽  
Vol 229 ◽  
Author(s):  
A. H. King
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Boundary Structure ◽  
Grain Boundary Structure ◽  
Transmission Electron ◽  
Dislocation Arrays ◽  
The Difference ◽  
Structure Calculations ◽  
Dislocation Spacing ◽  
The Ideal

AbstractWe present calculations of dislocation spacing for grain boundaries in zinc, and show that the spacings may be large enough to be resolved in conventional transmission electron microscopy even at extreme deviations from ideal coincidence misorientations. This effect is a result of the need for the dislocation arrays to accommodate slight differences between the ideal and actual axial ratios in addition to the difference between the ideal and actual misorientations. Recent observations of sliding behavior as a function of misorientation may also be rationalized within the framework of our structure calculations.

Investigation of Grain Boundary Structure and Composition of Bismuth Embrittled Copper Bicrystals with Aberration-Corrected Scanning Transmission Electron Microscopy

2012 ◽  
Vol 18 (S2) ◽  
pp. 346-347
Author(s):  
C. Wade ◽  
M. McLean ◽  
R. Vinci ◽  
M. Watanabe ◽  
L. Giannuzzi
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Grain Boundary ◽  
Scanning Transmission Electron Microscopy ◽  
Boundary Structure ◽  
Scanning Transmission Electron ◽  
Grain Boundary Structure ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Aberration Corrected

Extended abstract of a paper presented at Microscopy and Microanalysis 2012 in Phoenix, Arizona, USA, July 29 – August 2, 2012.

TEM Studies of Grain Boundary Structure in a Cast Polycrystalline Silicon

2005 ◽  
Vol 475-479 ◽  
pp. 1673-1676 ◽  
Author(s):  
Isamu Kuchiwaki ◽  
Takahiro Hirabayashi ◽  
Hiroshi Fukushima
Keyword(s):  
Electron Microscopy ◽  
Grain Boundary ◽  
Twin Boundary ◽  
Polycrystalline Silicon ◽  
High Resolution Electron Microscopy ◽  
Boundary Structure ◽  
Grain Boundary Structure ◽  
Transmission Electron ◽  
Resolution Electron ◽  
The Difference

Cast polycrystalline silicon for solar cell contains mostly straight twin boundaries which are thought to have little effect on the electrical activity. There are, however, some complicated grain boundaries in it. One of these boundaries consists of slightly curved and straight parts. The structure of this boundary was analyzed to investigate the difference of these two types of boundaries. The conventional transmission electron microscopy (TEM) found that this slightly curved boundary was the zigzag shaped boundary made by (11 _ ,2) and ( _ ,211) planes. High resolution electron microscopy (HREM) confirmed that (11 _ ,2) plane was the boundary of {112} Σ3 twin boundary which formed a straight grain boundary at the other end of the analyzed grain boundary, and also confirmed that ( _ ,2 11) plane was also the boundary of {112} Σ3 twin boundary which intersected with the former twin boundary at an angle of 120 [deg].

scholarly journals Effect of Aging Time on Crushing Performance of Al-0.5Mg-0.4Si Alloy for Safety Components of Automobile

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 608
Author(s):  
Jinkun Lu ◽  
Haichun Jiang ◽  
Lingying Ye ◽  
Daxiang Sun ◽  
Yong Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Tensile Test ◽  
Aging Time ◽  
Uniform Elongation ◽  
Total Elongation ◽  
Localized Deformation ◽  
Ductility Index ◽  
Transmission Electron ◽  
The Difference

The effect of aging time on the crushing performance of Al-0.5Mg-0.4Si alloy used for safety components of automobile was investigated by tensile test and crush test. Moreover, the microstructure of the alloy was investigated by transmission electron microscopy (TEM). The results show that the localized deformation ductility index, ΔAabs, which is defined as the difference between total elongation and uniform elongation, of Al-0.5Mg-0.4Si alloy is 6.5%, 7.0% and 8.5%, respectively, after being aged at 210 °C for 1, 3 and 6 h, and this tendency is the same as that of the crushing performance. The spacing of grain boundary precipitates (GBPs) from TEM results are found to be 94.9, 193.6 and 408.2 nm after being aged at 210 °C for 1, 3 and 6 h, respectively, and this tendency is same to that of ΔAabs. A mechanism about the relation between the spacing of GBPs and the ductility index ΔAabs has been proposed based on localized deformation around GBPs. With the increase of GBPs spacing, the ΔAabs increases, and the crushing performance is improved.

Influence of doping on crystal growth, structure and optical properties of nanocrystalline CaTiO3: a case study using small-angle neutron scattering

2015 ◽  
Vol 48 (3) ◽  
pp. 836-843 ◽  
Author(s):  
Oindrila Mondal ◽  
Manisha Pal ◽  
Ripandeep Singh ◽  
Debasis Sen ◽  
Subhasish Mazumder ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Optical Properties ◽  
Crystal Growth ◽  
Small Angle Neutron Scattering ◽  
Ionic Radius ◽  
Ionic Radii ◽  
Growth Structure ◽  
Transmission Electron ◽  
The Difference

The effect of dopant size (ionic radius) on the crystal growth, structure and optical properties of nanocrystalline calcium titanate, CaTiO3(CTO), have been studied using small-angle neutron scattering. X-ray diffraction, along with high-resolution transmission electron microscopy, confirms the growth of pure nanocrystalline CTO. Rietveld analysis reveals that the difference of ionic radii between dopant and host ions induces strain within the lattice, which significantly affects the lattice parameters. The induced strain, due to the difference of ionic radii, causes the shrinkage of the optical band gap, which is manifested by the redshift of the absorbance band. Mesoscopic structural analysis using scattering techniques demonstrates that the ionic radius of the dopant influences the agglomeration behaviour and particle size. A high-resolution transmission electron microscopy study reconfirms the formation of pure highly crystalline CTO nanoparticles.

Electron Microscopy Study of Stoichiometric and Non-Stoichiometric Titania

1997 ◽  
Vol 3 (S2) ◽  
pp. 669-670
Author(s):  
Solórzano I.G. ◽  
Kotani T. ◽  
Tuller H.L. ◽  
Van der Sande J.B.
Keyword(s):  
Electron Microscopy ◽  
Electric Activity ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Boundary Structure ◽  
High Tc Superconductors ◽  
High Tc ◽  
Grain Boundary Structure ◽  
Transmission Electron ◽  
Crystallographic Shear

It is currently well recognized that oxides are able to accommodate deviations from stoichiometry (1) and great advances in this understanding have been achieved by using transmission electron microscopy (TEM), particularly through lattice imaging and electron diffraction techniques (2). The physical properties of non-stoichiometric oxides are strongly influenced by their exact composition and for this reason they represent a class of materials with increasing and novel properties that are put to use in, for example, oxygen sensors and high-Tc superconductors. On the other hand, in electroceramic materials, such as TiO2, grain boundary structure and chemistry are important to be characterized in detail since these variables are responsible for the electric activity.Rutile (TiO2) can accommodate relatively large deviations from stoichiometry (TiOx with 2.0≥x≤ 1.75) by the crystallographic shear (CS) mechanism (1). The formation of CS planes is effectively a two-step process which involves the ordering of oxygen vacancies on a crystallographic plane and on their elimination by a shear of the lattice.

Microstructure of La1–xCaxMnO3 studied by transmission electron microscopy

2001 ◽  
Vol 16 (10) ◽  
pp. 2959-2965 ◽  
Author(s):  
Q. Chen ◽  
J. Tao ◽  
J. J. Zuo ◽  
J. J. H. Spence
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Colossal Magnetoresistance ◽  
Displacement Vector ◽  
Orthorhombic Unit Cell ◽  
Transmission Electron ◽  
Domain Boundaries ◽  
Synthesis Routes ◽  
Colossal Magnetoresistance Effect ◽  
The Ideal

Microstructures of La1-xCaxMnO3 compounds (x = ⅓ and 0.5) prepared with and without intermediate grinding were studied using transmission electron microscopy. A high density of antiphase boundaries (APBs) with displacement vector 1/2 〈111〉, indexed in orthorhombic unit cell, has been observed in bulk samples with no or minimum intermediate grinding. The nature of this APB is analyzed and found to bedue to the symmetry breaking introduced by the tilting of MnO6 octahedra relative to the ideal perovskite structure. Samples prepared using two intermediate grinds do not show these defects indicating that the microstructure can be controlled through synthesis routes. The effect of domain boundaries on the colossal magnetoresistance effect is discussed.

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