X-ray extinction contrast in deformed single crystals

Fries, E.; Spendel, M.; Philibert, J.

doi:10.1107/s0021889881009394

Cited by 7 publications

(5 citation statements)

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“…2b, 4b and 5b). It can be noted that the plastic deformation of sapphire occurs following two principal mechanisms: glides occurring in the h112 Å 0i direction on the (0001) basal plane, or glides in the h101 Å 0i directions on the {112 Å 0} prism planes (Kronberg, 1957;Barber & Tighe, 1965;Barber & Tighe, 1966;Heuer, 1966;Go Â scin Â ska & Auleytner, 1979;Fries et al, 1981;Lagerlo È f et al, 1994). In our sample, the domains are found to be nearly parallel to the [101 Å 0] direction, which lies on the (12 Å 10) plane, which is a plane of the crystallographic form {112 Å 0}, namely glide planes in the corundum.…”

Section: Discussionmentioning

confidence: 99%

Chemical and crystallographic investigations on the cracking of blue corundum, Al₂O₃, produced by the Verneuil technique

2000

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Corundum (Al2O3) boules grown by the Verneuil process generally crack along an irregular surface parallel to the elongation axis. In order to investigate the reasons for such cracking, a half boule of blue corundum, industrially produced following the Verneuil technique, was cut into slices (about 1 mm thick) parallel or normal to the elongation axis of the sample. All the slices were analysed by optical microscopy, energy dispersive spectrometry (EDS), flame atomic absorption spectrometry (FAAS), inductively coupled plasma atomic emission spectroscopy (ICP-AES) and by X-ray transmission topography, using synchrotron radiation. The two most interesting phenomena observed were: (a) a blue colour, the location of which was not homogeneous in the boule, but concentrated in a narrow (∼2 mm) ring in the outer region of the sample; (b) the development of a single crystal during the first stages of the growth and the formation of a macromosaic crystal, with domains that were slightly misoriented and subparallel to one another, in the middle part and at the top of the boule.

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Section: Discussionmentioning

confidence: 99%

Chemical and crystallographic investigations on the cracking of blue corundum, Al₂O₃, produced by the Verneuil technique

2000

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“…In particular, detection of dislocation arrangements on the scale of the sample (enlargement 20-100 times) by Berg-Barrett topography is complementary to transmission-electronmicroscopy observations that give information about individual dislocations. The sources of image contrast in a Berg-Barrett topograph, as well as the experimental setting used, have already been described by Fries, Guiberteau, Dominguez-Rodriguez, Cheong & Heuer (1989) and Fries, Spendel & Philibert (1981). In the present experiments, we used Cu Ks radiation and the divergence of the beam was 24'.…”

Section: Deformed-specimen Observations By Berg-barrett Topographymentioning

confidence: 96%

X-ray Berg–Barrett topography of the deformation substructure of stabilized zirconium oxide single crystals deformed at 1673 K

et al. 1994

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X‐ray Berg–Barrett topography has been used to check the nature of the slip systems that are activated during high‐temperature plastic deformation of single crystals and to follow the evolution of the microstructure with the strain. A study has been made of yttria fully stabilized zirconium oxide deformed by compression along the 〈001〉 direction at 1673 K. The {110} 〈10〉 slip system was activated.

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“…-Berg-Barrett topography can give further information on the plastic deformation. X-ray copper radiation has been used, with an experimental method already described in previous papers [16,17]. The intensity of the beam reflected by a single crystal can be modified in two cases :…”

Section: Specimen Observationsmentioning

confidence: 99%

“…(ii) When a distorted reflecting plane is used the intensity can be increased [ 17). This is called extinction contrast.…”

Section: Specimen Observationsmentioning

confidence: 99%

Dislocations in paratellurite TeO2 : elastic energies and plastic deformation

Péter¹,

Fries

Jánszky³

et al. 1986

Rev. Phys. Appl. (Paris)

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2014 La paratellurite TeO2 a des propriétés élastiques exceptionnellement anisotropes. Cela lui confère d'intéressantes possibilités d'applications acousto-optiques, qui dependent de sa perfection cristalline, d'où l'importance des dislocations dont les propriétés dépendent également de l'élasticité. Nous avons calcule l'énergie des dislocations ayant des vecteurs de Burgers [100], [110] et [001] ; dans certains cas, elle est maximale pour le caractère vis au lieu d'être minimale en élasticité isotrope. Par compression à vitesse constante, on a provoqué le glissement de dislocations, la contrainte a été appliquée le long de [110], [221], [100] et [001]. Les cristaux de TeO2 étaient fragiles au-dessous de 400 °C (0,7 de la température de fusion). Les études macroscopiques (microscopie optique, topographie de rayons X) ont seulement permis d'observer des plans de glissement : {100}, (001), {110} et { 10 1} semblent être activés, les vecteurs de Burgers 010> et 110> ont été déduits. Abstract. 2014 Paratellurite TeO2 is a crystal with exceptional anisotropic elasticity. This is the origin of interesting acousto-optical applications; as they depend on crystalline perfection, dislocations are of particular importance and their properties are also directly linked to elasticity. We have calculated the energy of dislocations with [100], [110] and [001] Burgers vectors : in some cases, it is maximum for screw character, instead of minimum for an isotropic medium. Constant strain rate compressions have been performed to induce dislocation glide; the stress was applied along [110], [221], [100] and [001]. TeO2 crystals were brittle below 400 °C (0.7 melting temperature). Macroscopic observations (optical microscopy, X ray topography) could only give information about slip planes : { 100}, (001), {110} and { 101} seem to be activated. The existence of 010> and 110> Burger's vectors is suggested.

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X-ray extinction contrast in deformed single crystals

Cited by 7 publications

References 1 publication

Chemical and crystallographic investigations on the cracking of blue corundum, Al₂O₃, produced by the Verneuil technique

Chemical and crystallographic investigations on the cracking of blue corundum, Al₂O₃, produced by the Verneuil technique

X-ray Berg–Barrett topography of the deformation substructure of stabilized zirconium oxide single crystals deformed at 1673 K

Dislocations in paratellurite TeO2 : elastic energies and plastic deformation

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X-ray extinction contrast in deformed single crystals

Cited by 7 publications

References 1 publication

Chemical and crystallographic investigations on the cracking of blue corundum, Al2O3, produced by the Verneuil technique

Chemical and crystallographic investigations on the cracking of blue corundum, Al2O3, produced by the Verneuil technique

X-ray Berg–Barrett topography of the deformation substructure of stabilized zirconium oxide single crystals deformed at 1673 K

Dislocations in paratellurite TeO2 : elastic energies and plastic deformation

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Chemical and crystallographic investigations on the cracking of blue corundum, Al₂O₃, produced by the Verneuil technique

Chemical and crystallographic investigations on the cracking of blue corundum, Al₂O₃, produced by the Verneuil technique