Dislocation glide

The dependence of creep rate on applied stress a is due to the climb force the higher CT, the higher the climb force jb tan 0, the more dislocations become unlocked per second, the more dislocations glide per second, and the higher is the strain rate. 

Fig. 13—Normalized o>/b as function of tglb, cta/b is the critical shear stress to move a dislocation from the B layer into the A layer, Q=(G -Gb)/(G +Gg), G and Gg are the shear moduli of A and B, b is the Burgers vector, fg is the thickness of one single B layer, and e is the angle between the A/B interfaces and the dislocation glide plane.

Gerk showed that Equation (2.1) is followed not only for metals, but also for ionic and covalent crystals if two adjustments are made. For covalent crystals, the temperature must be raised to a level where dislocations glide readily, but below the level where they climb readily. For ionic crystals, G (an average shear modulus) must be adjusted for elastic anisotropy. Thus it becomes ... 

Drag Effects. Dislocations gliding in real crystals encounter dissipative frictional forces which oppose their motion. These frictional forces generally limit the dislocation velocity to values well below the relativistic range. Such drag forces originate from a variety of sources and are difficult to analyze quantitatively. 

Real crystals can contain a large variety of different types of point, line, and planar crystal defects and other entities, such as embedded particles, which interact with dislocations and can act as obstacles to glide. Solute atoms are good examples of point defects that hinder dislocation glide by acting as centers of dilation... 

The motion of a crystal/crystal interface is either conservative or nonconservative. As in the case of conservative dislocation glide, conservative interface motion occurs in the absence of a diffusion flux of any component of the system to or from the... 

Glissile Motion of Sharp Interfaces by Interfacial Dislocation Glide... 

Movement of dislocations is a primary mechanism for plastic deformation. A dislocation s motion is impeded when they encounter obstacles, causing the stress required to continue the deformation process to increase. Grain boundaries are one of the obstacles that can impede dislocation glide, so the number of grain boundaries along a slip direction can be expected to influence the strength of a material. In the early 1950s, two researchers, Hall (1951) and Petch (1953),... 

Calcite and dolomite form large parts of the sedimentary continental crust. Consequently, their mechanical properties have been studied in some detail, and Wenk et al. (1983) have reviewed the rheology and associated microstructural development. Deformation takes place by both twinning and dislocation glide. 

The observed mircrostructures and rheological behavior are consistent with the suggestion by Durham, Goetze, and Blake (1977) that the dislocations glide essentially unhindered by other dislocations and that deformation is limited by the number of active dislocation sources. 

This study confirms our previous result [8] that even ultrashort shock experiments with laser and electric discharge guns are well suited to reproduce shock defects known to occur in naturally shocked minerals. For example, dislocation glide and twinning activated in the experimentally shocked specimens have also been detected in weakly shocked limestones from the Ries crater [50]. 

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