Dislocations and grain boundaries in polycrystalline ice: a preliminary study by synchrotron X-ray topography

Liu, F.; Baker, Ian; Yao, G.-D.; Dudley, Michael

doi:10.1007/bf00540695

Cited by 17 publications

(17 citation statements)

References 9 publications

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“…If these interstitials interact with grown-in dislocations during condensation, the dislocation structures are noticeably modified by climb. Later, Liu et al (1992a), using synchrotron white-beam X-ray topography (SWBXT), described below, showed that a loop-free zone is present next to grain boundaries in quenched polycrystalline ice because the interstitials migrate to the grain boundaries rather than condensing to form loops. Liu et al (1995a) also devised a straightforward method for determining whether a faulted loop on the basal plane was of interstitial or vacancy character.…”

Section: Conventional X-ray Topographymentioning

confidence: 98%

Imaging dislocations in ice

Baker

2003

Microscopy Res & Technique

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Three techniques have been used to study dislocations in ice: etch pitting-replication, transmission electron microscopy, and X-ray topography (XT). It is shown that, because ice is a weak absorber of X-rays and can be produced with a low dislocation density, allowing relatively thick specimens to be studied, the most useful technique is XT. The observations that have been made with conventional XT are briefly outlined. However, the introduction of high-intensity synchrotron radiation, with its concomitant short exposure times, showed that images obtained through conventional XT observations were of dislocations that had undergone recovery. The important dynamic observations and measurements that have been made using synchrotron X-ray topography are presented. Dynamic synchrotron X-ray topography observations of ice single crystals undergoing deformation in situ have shown that slip mainly occurs by the movement of screw and 60 degrees (1/3) [1120] dislocations on the basal plane, although non-basal slip by edge dislocations can also occur. The operation of Frank-Read and other dislocation multiplication sources have been clearly demonstrated and dislocation velocities have been measured. In contrast, in polycrystals, dislocation generation occurred at grain boundaries where there are stress concentrations before lattice dislocation generation mechanisms operate. Faulted dislocation loops have been determined to be mainly interstitial in both polycrystals and single crystals.

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Section: Conventional X-ray Topographymentioning

confidence: 98%

Imaging dislocations in ice

Baker

2003

Microscopy Res & Technique

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“…In order to decrease the thermal damage caused by mounting the sample on the base, supercooled water was sucked into the gap by capillary force. This decreased the damage area dramatically compared with the previous method in which the base, on which the ice sample was sitting, was warmed on a hot aluminium plate to melt the ice sample slightly (Liu et al 1992). After annealing, the specimens were transported to the National Synchrotron Light Source (NSLS), Brookhaven National Laboratory, New York, where they were transferred to a specially built cryostat, described elsewhere (Liu and Baker 1993).…”

Section: Sample Preparationmentioning

confidence: 99%

“…5.0" [Cannon, Schulson, Smith and Frost 1990). The subsequent specimen preparation has been detailed elsewhere (Liu et al 1992) and can be briefly outlined as follows: the crystallographic orientation of each grain was identified initially by the shape of etch pits (Higuchi 1958). A rectangular ice sample was cut with a jeweller's saw and shaved with a razor (Ahmad and Whitworth 1988).…”

Section: Sample Preparationmentioning

confidence: 99%

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Thermally induced dislocation loops in polycrystalline ice

Liu¹,

Baker²,

Dudley³

1995

Philosophical Magazine A

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“…According to our explanation, dislocation generation and multiplication should occur when the GB is under a shear stress and a resolved stress on the basal plane is provided. Since these are general geometrical conditions under which polycrystalline ice is deformed, and basal glide has been proven to be the main plastic deformation mechanism (Hobbs 1974), this dislocation generation mechanism should be dominant in the early stages of plastic deformation of polycrystalline ice (Liu et al 1992b).…”

Section: Dislocation Sources At Grain Boundariesmentioning

confidence: 99%