Quantum Behavior of the Twin Boundary and the Stacking Fault in hcp Helium Crystals

2015 ◽  
Vol 181 (1-2) ◽  
pp. 10-29
Author(s):  
V. A. Lykah ◽  
E. S. Syrkin
Keyword(s):  
Twin Boundary ◽  
Stacking Fault ◽  
Quantum Behavior ◽  
Helium Crystals

scholarly journals Modelling Electron Channeling Contrast Intensity of Stacking Fault and Twin Boundary Using Crystal Thickness Effect

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1696
Author(s):  
Hana Kriaa ◽  
Antoine Guitton ◽  
Nabila Maloufi
Keyword(s):  
Twin Boundary ◽  
Theoretical Approach ◽  
Stacking Fault ◽  
Thickness Effect ◽  
Specimen Thickness ◽  
Crystal Thickness ◽  
Contrast Imaging ◽  
Electron Channeling ◽  
Electron Intensity ◽  
Backscattered Electron

In a scanning electron microscope, the backscattered electron intensity modulations are at the origin of the contrast of like-Kikuchi bands and crystalline defects. The Electron Channeling Contrast Imaging (ECCI) technique is suited for defects characterization at a mesoscale with transmission electron microscopy-like resolution. In order to achieve a better comprehension of ECCI contrasts of twin-boundary and stacking fault, an original theoretical approach based on the dynamical diffraction theory is used. The calculated backscattered electron intensity is explicitly expressed as function of physical and practical parameters controlling the ECCI experiment. Our model allows, first, the study of the specimen thickness effect on the channeling contrast on a perfect crystal, and thus its effect on the formation of like-Kikuchi bands. Then, our theoretical approach is extended to an imperfect crystal containing a planar defect such as twin-boundary and stacking fault, clarifying the intensity oscillations observed in ECC micrographs.

Twin-boundary and stacking-fault energies in Al and Pd

1991 ◽  
Vol 43 (3) ◽  
pp. 2018-2024 ◽  
Author(s):  
Jian-hua Xu ◽  
W. Lin ◽  
A. J. Freeman
Keyword(s):  
Twin Boundary ◽  
Stacking Fault ◽  
Stacking Fault Energies

Temperature Coefficient for Twin Boundary Free Energy in 304 Stainless Steel: An Electron Microscope Study

1972 ◽  
Vol 30 ◽  
pp. 652-653
Author(s):  
L.E. Murr ◽  
R.J. Horylev
Keyword(s):  
Free Energy ◽  
Temperature Coefficient ◽  
Twin Boundary ◽  
Complex Function ◽  
Pure Metal ◽  
Stacking Fault ◽  
304 Stainless Steel ◽  
Pure Metals ◽  
Interfacial Adsorption ◽  
Image Position

It has been recently shown that, as generally assumed, the coherent twin boundary free energy and the intrinsic stacking fault free energy in fee pure metals are approximately related by a factor of 2 at constant temperature, i. e.,In the case of pure metals, the temperature coefficient assumes a simple Gibbs form for a general interface (stacking fault or twin boundary):where S is the interfacial entropy per unit area of interface. It is noted in Eq. (2) that the temperature coefficient for an idealized pure metal is always negative. Thus, in the absence of interfacial adsorption of vacancies or impurities [assumed in Eq. (2)], the stacking fault and twin boundary free energies will increase with increasing temperature, and will be related by Eq. (1).In the case of multicomponent (alloy) systems, the temperature coefficient becomes a complex function of component entropy contributions, surface adsorption and desorption, and their temperature dependence:

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