Saturation dislocation density

It is known that shock wave parameters namely peak pressure (strain rate) and pulse duration result in an increase in the mechanical properties of metals. Increasing the peak pressure results in increasing both the plastic strain and strain rate. Murr and Wilsdorf [37] observed that the dislocation density varies as a square root of the applied pressure. The result of the calculated dislocation density histories carried out at different strain rates reveals that the saturated dislocation density and the rate of dislocation multiplication increase with strain rate as illustrated in Fig 11. 

Pulse duration is related to the time required for the dislocations to reorganize in certain patterns. During the shock time rise, dislocations are generated leading to permanent plastic deformation. However, some of the dislocations can possibly retrace their path during wave release reversibly [38], Pulse duration may influence the amount dislocation reversibility and as a result the saturated dislocation density. Fig. 12 shows that the saturation density of... 

Nanocrystalline materials comprising sub-100 / metal particles, when compressed to 50% of their bulk density, show properties (specific heat, thermal conductivity, saturation magnetization and critical temperature for superconductivity) provocatively different from those of their crystalline or glassy counterparts.(48) It is well known that the interfaces of mechanically reduced composites are effective in interacting with dislocations and with flux lines in superconducting composites. Precursor materials for the preparation of ultrafine filamentary composites can also be imagined. Here the combinations of interphasial boundaries and dislocations can... 

---