Force-elongation crystals

This is consistent with data from atomic force microscopy (AFM) examination of Cu-MOF deposits submitted to a cathodic input. As shown in Figure 5.8a, pristine Cu-MOF particles appeared as elongated crystals 100-200 nm in size with a corrugated surface texture. Upon application of a constant potential step at -250 mV... 

The initial portion of the virgin force-elongation curve is approximately linear, and the crystals support compressional forces. 

As the stress is reduced, the rate of power-law creep (eqn. (19.1)) falls quickly (remember n is between 3 and 8). But creep does not stop instead, an alternative mechanism takes over. As Fig. 19.4 shows, a polycrystal can extend in response to the applied stress, ct, by grain elongation here, cr acts again as a mechanical driving force but, this time atoms diffuse from one set of the grain faces to the other, and dislocations are not involved. At high T/Tm, this diffusion takes place through the crystal itself, that... 

Crystals formed under small driving force conditions (see Section 3.2) in a dilute ambient phase, such as the vapor phase or solution phase, will generally exhibit polyhedral forms, irrespective of their size. Even crystals of micrometer size, such as clay minerals, show polyhedral forms. However, there are crystals that show elongated needle forms that resemble whiskers, coils, hollow tubes, and even ice cream cones (see Figs. 2.2 (a), (b)) others exhibit tree-like polycrystalline aggregates of dendrites (see Fig. 2.2 (c)). 

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