Structural materials mobile dislocations

The work hardening demonstrated by the slider experiments clearly shows the effect of dislocation mobility on this rock-salt-structure material, and it is not unexpected to find much evidence for a load hardness effect with a range of n values at room temperature depending on plane and direction this is shown in Table 4.3. Dislocation mobility under the influence of the stress fields found in indentation hardening also manifests itself as an indentation creep effect as shown in Figure 4.11. 

The brittle transition region is that range of temperatures where the important response mechanisms of the material to stress are becoming inactive. This may be the mobility of dislocations for a metal, or the ability of the molecules to slide over one another in a polymer. Curves of ductility versus temperature for several important structural materials are shown in Fig. 3.4. 

As mentioned, the solid electrolytes are sintered metal oxides with mobility of ions where the ionic conductivity is influenced by both the microstructure and geometry. The effects of composition, structure, microstructure, and strain on ionic transport at grain boundary provided complementary tools for futiu-e developments in solid electrolyte materials. Among these, a particular attention was given to the impact on ionic transport of defects in various types of structures, dislocations, grain boundaries, and heterostructure interfaces. The design of such structural properties also considered the achievements of the development in nanotechnologies. 

At low temperature (<0.37)ji, I m being the melting temperature ofthe irradiated material) the atomic mobility is sufficiently low so that all defects are destroyed principally by mutual recombinations. The only remaining traces of irradiation in the material are small dislocation clusters or loops that nevertheless harden and embrittle structures exposed to irradiation ... 

Because perfect dislocations are observed in high-stress conditions where a hydrostatic component is present in the stress tensor, it is of interest to check the effect of such a hydrostatic pressure on their core structure configuration and mobility. One can expect three kinds of effects due to pressure (i) the material is usually stiffer (this is the case for silicon), with an increase of elastic constants that affect the strain field around the core, (ii) the core structure and its stability could be modified, and (iii) pressure could favor dislocation core mobility along certain directions. One may then wonder whether theoretical investigations of non-dissociated perfect dislocations are really representative of experiments. 

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