scholarly journals Probing anisotropic mechanical behaviour in carbamazepine form III

CrystEngComm ◽  
2021 ◽  
Author(s):  
Benjamin P. A. Gabriele ◽  
Craig J. Williams ◽  
Matthias E. Lauer ◽  
Brian Derby ◽  
Aurora J. Cruz-Cabeza
Keyword(s):  
Single Crystals ◽  
Slip Plane ◽  
Mechanical Behaviour ◽  
Molecular Simulations ◽  
Afm Imaging

Nanoindentation measurements in single crystals of carbamazepine form III show that the (020) face is stiffer and harder than the (002) and (101) faces. AFM imaging and molecular simulations reveal that the (020) plane is the most likely slip plane.

Brittle Behaviour in Aspirin Crystals: Evidence of Spalling Fracture

2020 ◽  
Author(s):  
Benjamin P. A. Gabriele ◽  
Craig J. Williams ◽  
Douglas Stauffer ◽  
Brian Derby ◽  
Aurora J. Cruz-Cabeza
Keyword(s):  
Surface Roughness ◽  
Atomic Force Microscopy ◽  
Single Crystals ◽  
Spalling Fracture ◽  
Force Microscopy ◽  
Atomic Force ◽  
Afm Imaging

<div> <div> <div> <p>Single crystals of aspirin form I were cleaved and indented on their dominant face. Upon inspection, it was possible to observe strongly anisotropic shallow lateral cracks due to the extreme low surface roughness after cleavage. Atomic Force Microscopy (AFM) imaging showed spalling fractures nucleating from the indent corners, forming terraces with a height of one or two interplanar spacings d100. The formation of such spalling fractures in aspirin was rationalised using basic calculations of attachment energies, showing how (100) layers are poorly bonded when compared to their relatively higher intralayer bonding. An attempt at explaining the preferential propagation of these fractures along the [010] direction is discussed. </p> </div> </div> </div>

Brittle Behaviour in Aspirin Crystals: Evidence of Spalling Fracture

2020 ◽  
Author(s):  
Benjamin P. A. Gabriele ◽  
Craig J. Williams ◽  
Douglas Stauffer ◽  
Brian Derby ◽  
Aurora J. Cruz-Cabeza
Keyword(s):  
Surface Roughness ◽  
Atomic Force Microscopy ◽  
Single Crystals ◽  
Spalling Fracture ◽  
Force Microscopy ◽  
Atomic Force ◽  
Afm Imaging

<div> <div> <div> <p>Single crystals of aspirin form I were cleaved and indented on their dominant face. Upon inspection, it was possible to observe strongly anisotropic shallow lateral cracks due to the extreme low surface roughness after cleavage. Atomic Force Microscopy (AFM) imaging showed spalling fractures nucleating from the indent corners, forming terraces with a height of one or two interplanar spacings d100. The formation of such spalling fractures in aspirin was rationalised using basic calculations of attachment energies, showing how (100) layers are poorly bonded when compared to their relatively higher intralayer bonding. An attempt at explaining the preferential propagation of these fractures along the [010] direction is discussed. </p> </div> </div> </div>

Effect of Hydrostatic Pressure on Geometry of Slip in Silicon Iron Single Crystals

1983 ◽  
Vol 22 ◽  
Author(s):  
A.V. Dobromyslov ◽  
G.V. Dolgikh ◽  
N.I. Talutz ◽  
V.T. Shmatov ◽  
B. I. Beresnev
Keyword(s):  
Hydrostatic Pressure ◽  
Single Crystals ◽  
Slip Plane ◽  
Special Structure ◽  
Normal Stresses ◽  
Silicon Iron ◽  
Screw Dislocations ◽  
Effect Of Pressure ◽  
Effect Of Hydrostatic Pressure

ABSTRACTThe effect of the pressure 550MPa on the choice of the acting slip plane in the single crystals of Fe−2,9%Si was studied. It was established that the presence of pressure resulted in the increase of the slip asymmetry. The effect of pressure is attributed to the action of normal stresses and to the special structure of screw dislocations.

scholarly journals Twinning in Czochralski-Grown 36°-RY LiTaO3 Single Crystals

Crystals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1009
Author(s):  
Yutaka Ohno ◽  
Yuta Kubouchi ◽  
Hideto Yoshida ◽  
Toshio Kochiya ◽  
Tomio Kajigaya
Keyword(s):  
Single Crystals ◽  
Slip Plane ◽  
Edge Dislocation ◽  
Lithium Tantalate ◽  
Initiation Site ◽  
The Other ◽  
Burgers Vector ◽  
Partial Dislocations ◽  
Dislocation Arrays ◽  
Extension Direction

The origin of twinning during the Czochralski (CZ) growth of 36°-RY lithium tantalate (LiTaO3) single crystals is examined, and it is shown that lineages composed of dislocation arrays act as an initiation site for twinning. Two types of lineages expand roughly along three different {12¯10} planes and two different {11¯00} planes. The former lineages and some latter lineages are composed of two types of mixed-dislocations with different Burgers vectors, while the other lineages are composed of only one type of edge-dislocation. All the dislocations have the Burgers vector of ⟨12¯10⟩ type with the compression side at the +Z side. Twin lamellae on {101¯2} are generated at a lineage during the CZ growth. We have hypothesized that dislocations in the lineage with b = 1/3⟨12¯10⟩ change their extension direction along a slip plane of {101¯2}, and they dissociate into pairs of partial dislocations with b = 1/6⟨22¯01⟩and 1/6⟨02¯21¯⟩ forming twin lamellae on {101¯2}.

The mechanical behaviour of single crystals of metals, in particular copper

1957 ◽  
Vol 240 (1222) ◽  
pp. 304-320 ◽  
Keyword(s):  
Shear Stress ◽  
High Temperature ◽  
Single Crystals ◽  
Mechanical Behaviour ◽  
Critical Shear Stress ◽  
Deformation Bands ◽  
Hexagonal Metals

With single crystals of copper, measurements have been made on the variation of the amount of easy glide with the orientation of the crystal axes relative to the direction of tension. At —180° C it has been shown that this variation can be quantitatively expressed by a specific hardening on the active glide planes, which does not exist for the latent glide planes, and a general hardening which applies to both active and latent glide planes. This is compared with the behaviour of hexagonal metals. The occurrence of double glide is analyzed. The variation of glide properties with temperature has been measured for one particular orientation, and the coefficient of specific hardening shown to be roughly independent of temperature. The critical shear stress is also very little affected by temperature, but depends somewhat on orientation. The glide behaviour at high temperature has been found to be influenced largely by the occurrence of deformation bands. A few measurements have been made on gold.

Computer programANIZCfor the calculation of diffraction contrast factors of dislocations in elastically anisotropic cubic, hexagonal and trigonal crystals

2003 ◽  
Vol 36 (1) ◽  
pp. 160-162 ◽  
Author(s):  
András Borbély ◽  
Juliana Dragomir-Cernatescu ◽  
Gábor Ribárik ◽  
Tamás Ungár
Keyword(s):  
Computer Program ◽  
Single Crystals ◽  
Programming Language ◽  
Slip Plane ◽  
Anisotropic Medium ◽  
Mechanical Equilibrium ◽  
Strain Anisotropy ◽  
Diffraction Contrast ◽  
Contrast Factor ◽  
Distortion Tensor

The computer programANIZChas been developed using the Pascal programming language for the calculation of diffraction contrast factors of dislocations in elastically anisotropic cubic, hexagonal and trigonal crystals. The contrast factor is obtained numerically by integrating the angular part of the distortion tensor in the slip plane. The distortion tensor is calculated by solving the sextic equation provided by the mechanical equilibrium of a single dislocation in an infinite anisotropic medium. The contrast factors can be used for the interpretation of strain anisotropy as obtained from peak profile measurements made on either single crystals, textured polycrystals or powders.

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