Fish Antifreeze Proteins and the Creep of Polycrystalline Ice

AbstractCreep curves obtained from the polycrystalline ice samples containing low concentrations of antifreeze glycopeptides (AFGPs) do not show the re-accelerating or tertiary creep that is found in pure ice samples. Previous work has shown that AFGPs inhibit grain-boundary migration in ice and the present results are consistent with this, as tertiary creep is associated with nucleation and growth of new ice grains.

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Development of microstructure in the high-temperature deformation of ice

Annals of Glaciology ◽

10.1017/s0260305500013562 ◽

1996 ◽

Vol 23 ◽

pp. 293-302 ◽

Cited By ~ 6

Author(s):

Christopher J. L. Wilson ◽

Yanhua Zhang

Keyword(s):

Grain Boundary ◽

Boundary Migration ◽

Time Lapse ◽

Grain Structure ◽

High Temperature Deformation ◽

Temperature Deformation ◽

Grain Boundary Migration ◽

Crystallographic Slip ◽

Polycrystalline Ice ◽

Time Lapse Photography

Microstructural changes in three sets of experiments involving crystallographic slip in anisotropic polycrystalline ice are described and interpreted with the aid of computer models. The development of microstructure was followed using time-lapse photography and transmitted light observations with deformation undertaken in plane strain and at a temperature of approximately –1°C. The deformation within a grain aggregate that accompanies axial shortening is always heterogeneous on a grainscale. The extent of inhomogeneity varies depending on the pre-existing grain structure and the way it can accommodate intragranular slip. Grain interactions are extremely important in determining the bulk deformation and the degree of grain-boundary migration. A consequence of shortening of the aggregate is the formation of high stresses between neighbouring grains and under the appropriate conditions there may be either grain-boundary migration or melting at these sites. Where a sample undergoes translation and shear during deformation, anisotropic grains in the appropriate orientation undergo bending. A buckle instability may then develop and much of the strain is accommodated by grains in easy-glide orientations. In such situations, the ice undergoes extensive recrystallization and grain growth that is concentrated in the areas of greatest buckling.

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Development of microstructure in the high-temperature deformation of ice

Annals of Glaciology ◽

10.3189/s0260305500013562 ◽

1996 ◽

Vol 23 ◽

pp. 293-302 ◽

Cited By ~ 6

Author(s):

Christopher J. L. Wilson ◽

Yanhua Zhang

Keyword(s):

Grain Boundary ◽

Boundary Migration ◽

Time Lapse ◽

Grain Structure ◽

High Temperature Deformation ◽

Temperature Deformation ◽

Grain Boundary Migration ◽

Crystallographic Slip ◽

Polycrystalline Ice ◽

Time Lapse Photography

Microstructural changes in three sets of experiments involving crystallographic slip in anisotropic polycrystalline ice are described and interpreted with the aid of computer models. The development of microstructure was followed using time-lapse photography and transmitted light observations with deformation undertaken in plane strain and at a temperature of approximately –1°C. The deformation within a grain aggregate that accompanies axial shortening is always heterogeneous on a grainscale. The extent of inhomogeneity varies depending on the pre-existing grain structure and the way it can accommodate intragranular slip. Grain interactions are extremely important in determining the bulk deformation and the degree of grain-boundary migration. A consequence of shortening of the aggregate is the formation of high stresses between neighbouring grains and under the appropriate conditions there may be either grain-boundary migration or melting at these sites. Where a sample undergoes translation and shear during deformation, anisotropic grains in the appropriate orientation undergo bending. A buckle instability may then develop and much of the strain is accommodated by grains in easy-glide orientations. In such situations, the ice undergoes extensive recrystallization and grain growth that is concentrated in the areas of greatest buckling.

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Comparison between experiment and computer modelling of plane-strain simple-shear ice deformation

Journal of Glaciology ◽

10.3189/s0022143000003786 ◽

1994 ◽

Vol 40 (134) ◽

pp. 46-55

Author(s):

C.J. L. Wilson ◽

Y. Zhang

Keyword(s):

Grain Size ◽

Grain Boundary ◽

Simple Shear ◽

Computer Modelling ◽

Boundary Migration ◽

Stress And Strain ◽

Grain Boundary Migration ◽

Lattice Orientation ◽

Polycrystalline Ice ◽

Good Agreement

AbstractAn examination of both experiments and computer models of polycrystalline ice undergoing a simple shear suggests that there is good agreement. The model has correctly reproduced the deformational and microstructural features caused by glide on (0001) in the ice aggregates. This success is particularly prominent for those ice grains with a lattice orientation suitable for hard or easy glide or kinking, and where there is a sub-horizontal с axis and a larger grain-size. A limitation may be that the model cannot explicitly simulate recrystallization and grain-boundary migration, which are two other important processes operating jointly with glide in experimentally deformed ice. However, through the use of the models, it is possible to show how kinematic factors can control the processes of recrystallization. The localization of recrystallization in the polycrystalline ice aggregate is determined by the stress and strain variations between neighbouring grains.

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Comparison between experiment and computer modelling of plane-strain simple-shear ice deformation

Journal of Glaciology ◽

10.1017/s0022143000003786 ◽

1994 ◽

Vol 40 (134) ◽

pp. 46-55 ◽

Cited By ~ 29

Author(s):

C.J. L. Wilson ◽

Y. Zhang

Keyword(s):

Grain Size ◽

Grain Boundary ◽

Simple Shear ◽

Computer Modelling ◽

Boundary Migration ◽

Stress And Strain ◽

Grain Boundary Migration ◽

Lattice Orientation ◽

Polycrystalline Ice ◽

Good Agreement

AbstractAn examination of both experiments and computer models of polycrystalline ice undergoing a simple shear suggests that there is good agreement. The model has correctly reproduced the deformational and microstructural features caused by glide on (0001) in the ice aggregates. This success is particularly prominent for those ice grains with a lattice orientation suitable for hard or easy glide or kinking, and where there is a sub-horizontalсaxis and a larger grain-size. A limitation may be that the model cannot explicitly simulate recrystallization and grain-boundary migration, which are two other important processes operating jointly with glide in experimentally deformed ice. However, through the use of the models, it is possible to show how kinematic factors can control the processes of recrystallization. The localization of recrystallization in the polycrystalline ice aggregate is determined by the stress and strain variations between neighbouring grains.

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The effect of particles on creep rate and microstructures of granular ice

Journal of Glaciology ◽

10.3189/002214308785836959 ◽

2008 ◽

Vol 54 (186) ◽

pp. 533-537 ◽

Cited By ~ 9

Author(s):

Min Song ◽

Ian Baker ◽

David M. Cole

Keyword(s):

Creep Rate ◽

Grain Boundary ◽

Dynamic Recrystallization ◽

Grain Boundaries ◽

Initial Stress ◽

Nucleation Rate ◽

Boundary Migration ◽

Nucleation And Growth ◽

Grain Boundary Migration ◽

Before And After

AbstractThe microstructures of particle-free granular freshwater ice and ice containing 1 wt.% of 50 ± 10 mm uniformly distributed particles were investigated before and after compressive creep to ∼10% strain with stresses of 1.45 MPa at −10°C and 0.4 MPa at −5°C. Creep rates of particle-containing ice were always higher than those of particle-free ice. For an initial stress of 1.45 MPa at −10°C, dynamic recrystallization occurred with new grains nucleating and growing along grain boundaries for both sets of specimens, and the ice with particles showed a higher nucleation rate. Under creep with an initial stress of 0.4 MPa at −5°C, dynamic recrystallization also occurred by the nucleation and growth of new grains along the grain boundaries for ice containing particles, but recrystallization in the particle-free ice occurred through grain boundary migration.

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Measurement of solute segregation to grain boundaries in the AEM: A review

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100105096 ◽

1988 ◽

Vol 46 ◽

pp. 606-607

Author(s):

D. B. Williams ◽

A. D. Romig

Keyword(s):

Grain Boundary ◽

Grain Boundaries ◽

Boundary Migration ◽

Grain Boundary Migration ◽

Boundary Misorientation ◽

Collector Plate ◽

Segregation Process ◽

Grain Boundary Misorientation ◽

Structure Boundary ◽

Equilibrium Segregation

The segregation of solute or imparity elements to grain boundaries can occur by three well-defined processes. The first is Gibbsian segregation in which an element of minimal matrix solubility confines itself to a monolayer at the grain boundary. Classical examples include Bi in Cu and S or P in Fe. The second process involves the depletion of excess matrix solute by volume diffusion to the boundary. In the boundary, the solute atoms diffuse rapidly to precipitates, causing them to grow by the ‘collector-plate mechanism.’ Such grain boundary diffusion is thought to initiate “Diffusion-Induced Grain Boundary Migration,” (DIGM). This process has been proposed as the origin of eutectoid transformations or discontinuous grain boundary reactions. The third segregation process is non-equilibrium segregation which result in a solute build-up around the boundary because of solute-vacancy interactions.All of these segregation phenomena usually occur on a sub-micron scale and are often affected by the nature of the grain boundary (misorientation, defect structure, boundary plane).

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Domain coarsening by grain boundary migration in ordered Ni4Mo

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100144279 ◽

1986 ◽

Vol 44 ◽

pp. 560-561

Author(s):

K. Vasudevan ◽

H. P. Kao ◽

C. R. Brooks ◽

E. E. Stansbury

Keyword(s):

Grain Boundary ◽

Grain Boundaries ◽

Short Range ◽

Boundary Migration ◽

Grain Boundary Migration ◽

Rapid Cooling ◽

Temperature Range ◽

Fee Structure ◽

Domain Coarsening ◽

Boundary Reaction

The Ni4Mo alloy has a short-range ordered fee structure (α) above 868°C, but transforms below this temperature to an ordered bet structure (β) by rearrangement of atoms on the fee lattice. The disordered α, retained by rapid cooling, can be ordered by appropriate aging below 868°C. Initially, very fine β domains in six different but crystallographically related variants form and grow in size on further aging. However, in the temperature range 600-775°C, a coarsening reaction begins at the former α grain boundaries and the alloy also coarsens by this mechanism. The purpose of this paper is to report on TEM observations showing the characteristics of this grain boundary reaction.

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