Grain boundaries Persistent

Fig. 8.60 Schematic diagrams showing common surface profiles produced during fatigue (a) coarse slip and crack initiation adjacent to grain boundaries (b) extrusions and intrusions (c) coarse slip within a persistent slip band (after Lynch Y...

The complete monolayer is modeled by an NVT ensemble with again deformable periodic boundary conditions, where fixed particle number N and fixed area V results in a constant coverage, which was chosen to be unity [102, 301]. This models the situation where either the physical or the grain boundaries prohibit a thermal expansion of the complete monolayer in the graphite plane. Also in this case, a melting transition to a modulated fluid occurs, but the transition is now located at about 87 K see the heat capacity anomaly in Fig. I9b. The transition does not show any noticeable hysteresis nor appreciable size effects, and the modulated fluid persists up... 

Although liquid crystals have been known for more than 100 years, discovering the structures of their many thermodynamic phases is an activity that persists to this day [1]. The sheer variety has been impressive, including such novelties as uniaxial, biaxial, and ferroelectric fluids phases with hexatic order and chiral phases such as the blue phase (BP) and twist grain boundary (TGB) phase, which are stabilized by a lattice of defects. Many of these phases are unique in condensed matter physics their presence never fails to challenge our notions of how matter can arrange itself in the aggregate. 

It is well known that shp bands, twins, interphases, grain boundaries, and constituent particles are classical sites for crack initiation. Moreover, persistent slip band... 

Fig. 1.49 Appearance of micro cracks along persistent grain boundary in aluminum a grains have heavily undergone plastic slips, b upon electropolishing the specimen slip lines almost disappear, but grain border remain visible because affected by micro cracks, c and d after repeating cycling and electropolishing...

Fig. 1.57 Schematic of event progression that goes from a pore formation into persistent slip bands in some superficial grains, b growth and coalescence of submicroscopic damage with MSC formation, c grain boundary break-through by MSC and macro crack formation...

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