Grain boundary, tilt

As was already shown in the past, for instance by Aust and Rutter or Shvindlerman et al. - the mobility of tilt grain boundaries depends on axis and angle cp of... 

Fig. 5 Mobility dependemce of tilt grain boundaries on rotation angle in pure Al (Al II)...

Fig. 7 Dependence of activation enthalpy H, preexponential factor A and compensation temperature f, in pure Alfor 38.2° ( )and 40.5° (M)< 111 >-tilt grain boundaries.

Fig. 10 Arrhenius plot of mobility of (a) 38.2° and (b) 40.5°<111> tilt grain boundaries in pure Al and pure Al doped with 10 ppm Ga.

Fig. 11. Concentration dependence of mobility for 38.2°(G), and4O.5°(0) tilt grain boundaries at different temperutures.

Fig. 12 Migration activation enthalpy H (a) and mobility pre-exponential factor Ao (b) for 38.2° (C>)and 40.5° ( tilt grain boundaries as a function of Ga concentration.

D. A. Molodov, U. Czubayko, G. Gottstein and L. S. Shvindlerman, Mobility of <111> tilt grain boundaries in the vicinity of the special misorientation S7 in bicrystals of pure aluminium, Scripta metull. mater. 32 529 (1995). 

J. W. Rutter and K. T. Aust, Migration of <111> tilt grain boundaries in high purity lead, Acta Metall. 13 181 (1965). 

A high-angle tilt grain boundary results when 6 > 15°. For 6 < 10°, a low-angle tilt grain boundary results, and Eq. (1.37) can be simplified to tmO 6 = b/h. In a similar manner, a twist grain boundary is a set of screw dislocations. 

Figure 1.35 Representation of a tilt grain boundary. From K. M. Rails, T. H. Courtney, and J. Wulff, Introduction to Materials Science and Engineering. Copyright 1976 by John Wiley Sons, Inc. This material is used by permission of John Wiley Sons, Inc.

Example 1 The tilt grain boundary in Fig. B.4a is singular with respect to its tilt angle.4 The boundary in Fig. B.4c is vicinal to the singular boundary... 

Figure B.2 Symmetric large-angle (113)(TlO] tilt boundary in A1 viewed along the [110] tilt axis by high-resolution electron microscopy. The tilt angle is 50.48°. The inset shows a simulated image [4], Reprinted, by permission, from K.L. Merkle, L.J. Thompson, and F. Phillipp, Thermally activated step motion observed by high-resolution electron microscopy at a (113) symmetric tilt grain-boundary in aluminum," Philosophical Magazine Letters, vol. 82. pp. 589-597. Copyright (c) 2002 by Taylor and Francis Ltd., http //www.tandf.co.uk/journals.

K. L. Merkle, L. J. Thompson, and F. Phillipp. Thermally activated step motion observed by high-resolution electron microscopy at a (113) symmetric tilt grain-boundary in aluminium. Phil. Mag. Lett., 82 589-597, 2002. 

Figure 35. Impedance spectra of the cell 02, Pt I SrTi031 SrTi031 Pt, 02 as function of d.c. bias. Electrodes are parallel to the bicrystal boundary (Z5 tilt grain boundary, iron content 2 x 1018 cnT3). Both bulk and boundary resistances are predominantly electronic resistances.222 Reprinted from I. Denk, J. Claus and J. Maier, J. Electrochem. Soc., 144 (1997) 3526-3536. Copyright 1997 with permission from The Electrochemical Society.

A. Luque et al Molecular dynamics simulation of crack tip blunting in opposing directions along a symmetrical tilt grain boundary of copper bicrystal. Fatigue Fract. Eng. Matls. Struct. 30, 1008-1015 (2007)... 

We begin our geometric discussion with the case of pure tilt boundaries on the grounds that the connection between dislocations and the boundary is most evident visually in this case. As was discussed in some detail in chap. 9, a tilt grain boundary is characterized by a simple misorientation between the two grains as was discussed in chap. 9. The intent of this section is to illustrate that a simple superposition of the elastic displacements implied by the Volterra solution for straight dislocations discussed in chap. 8 can lead to exactly the same type of misorientation. 

Fig. 11.9. Energy of tilt grain boundary as a function of misorientation angle (adapted from Sutton andBalluffl (1995)).

Rittner J. D. and Seidman D. N., (110) Symmetric Tilt Grain-Boundary Structures in fee Metals with Low Stacking-Fault Energies, Phys. Rev. B54, 6999 (1996). 

Further work on the misorientation dependence by Ivanov and coworkers indicated as a function of 6 an exponential decrease in the critical current across the interface in [001] tilt grain boundaries in YBCO films [10.7]. The critical current density [according to refs. 10.4, 10.7, 10.51, 10.59, and 10.60] for grain boundaries with misorientation about [001] is shown in Fig. 10.1. 

An HREM image of the = 5, (310) symmetric tilt grain boundary in NiO... 

Fig. 10.5. HREM image of [001] tilt grain boundary in NiO. The = 5/(310) symmetrie tilt grain boundary shows two variants, separated by a small step. The sehematie CSL drawing (below) illustrates that the step introduees an effeetive rigid-body translation parallel to the grain boundary [10.30].

Fig. 10.6. HREM image of the (510) symmetric tilt grain boundary in NiO 6 = 22.6°). Note the well-connected (200) planes across the grain boundary between the regions of misfit [10.28].

Fig. 10.8. HREM images of various 90° grain boundaries in YBCO (a) [100] tilt, a and b interchanged across boundary (b) [100] tilt grain boundary showing two distinct facets, the (013) symmetric boundary with the CuOi planes joining at the interface and the (010)(001) asymmetric grain boundary (c) same as the asymmetric boundary in (b), but viewed at 90°, with one grain in the [001] projection (d) tilt and twist facets combined (continues overleaf).

Clearly, since the Cu02 planes, which play an essential role in the superconducting transport, are disrupted across the (010)(001) boundaries, they are expected to show weak-link behavior. However, since the Cu02 planes are continuous across (013)(013) boundaries, the latter may provide good supercurrent conducting paths across the 90° [100] tilt grain boundaries, resulting possibly in weak-link free behavior [10.43]. Measurements across individual... 

However, in contrast to the previously described tilt grain boundaries the boundary is not planar and as well defined as in the (010)(001) boundary. Thus, although the grain boundary has mainly twist character, the grain boundary is of mixed type and it is evident that the crystalline structure does not abruptly change across the boundary. It appears possible that the irregular shapes of the boundary plane could increase the contact area of the Cu02 planes across the boundary. 

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