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It has been reported that during severe plastic deformation, localized slip followed by dynamic recovery results into refined grains with high density of high angle grain boundaries in the primary coarse grains.
However, the extent of grain refining by this technique is limited (upto 200 nm) and further reduction in grain size is very difficult.
TEM observations also showed the formation of refined grains with high or low angle grain boundaries within the coarse grains.
Therefore, pile up of dislocations near these grain boundaries, could lead to grain boundary sliding and grain rotation resulting in increase in ductility.
Number Fraction Number Fraction (a) (b) Fig.3 EBSD pattern of grain misorientation angle for (a) 95% cryo rolled Cu + 175 oC HT; (b) 95% cryo rolled Cu + 225 oC HT.

The maximum cutting depth (agmax) of single abrasive grain is obtained by 21 max 4 � � � � � � = ep ds w g da CN a � � , (2) where �w is the feed rate, �s is tangential speed of the wheel, Nd is the number of dynamic effective cutting edge, C is the cutting constant, ap is cutting depth and de is the equivalent diameter of the wheel.
The number of the dynamic effective cutting edge (Nd) is the measured effective cutting edge on the unit area along the contract arc of the wheel and the workpiece.
In actual situation, the exponents � and � are related to exponents p and m. p reflects the relationship between the dynamic cut-in depth ads and the number of static effective cutting edges of unit length.
(9) When m=0, it means some grains are blunt and while m=1, it shows the triangle grain.
Acknowledgements Author gratefully acknowledges Heilongjiang Province Natural Science Foundation and the Harbin City Science Foundation of China Heilongjiang Province for their Support of this work: The contact number is E0218 and 2002AFXXJ046.

Plate-like grain microstructures formed on the bottom part of the pellet, and vicinity of the surface was dense.
The plate-like grain was oriented in the ab-plane direction.
A number of studies have investigated the preparation of In2O3(ZnO)m as new transparent conducting electrodes for use in a variety of electronics devices, and the synthesis of a highly electrical conductive compound In2O3(ZnO)3 in a solid state reaction at low reaction temperature is required.
In the present study, since the ab-plane direction of the In2O3(ZnO)3 grain has high electrical conductivity, the plate-like grain was grown selectively.
In addition, for the silica substrate the plate-like grain was deposited by microwave heating.

They also suggested that significant dynamic recovery and recrystallization occurred during the deformation process, resulting in a large number of grain orientations with very little texture.
It indicates a weak texture and a large number of orientations present.
For comparison, average grain size of as-received arc-melted buttons is less than 200 µm. 0 100 200 300 400 500 600 700 800 900 800 900 1000 1100 1200 Rolling temperature (°C) Average grain size (µm) Fig. 5.
Average grain size as a function of rolling temperature, at a total reduction of about 80%.
These results also suggested that significant dynamic recovery and recrystallization occurred during the deformation process, resulting in a large number of grain orientations with very little texture.

(2) Dgeff and Dgbeff are respectively, the effective B redistribution coefficients in the grains and the grain boundaries.
(4) Di = D0 exp (–Ea/KT) is the intrinsic diffusion coefficient in single-crystal Si, K is the Boltzmann constant, T is the annealing temperature, Ea is the activation energy, p is the holes concentration, ni is the electron intrinsic concentration, Csol is the B solubility limit, β is the ratio of the diffusivity induced by charged vacancies (β=Di+/Di0), m is the medium number of B–Si atoms in small clusters formed within the grains, γgbEnh is a pre-exponential factor for the adjustment of the TED rate within the grain boundaries and Eb is the energy barrier height to the grain boundaries; which depends on the average grain size Lg and the density of trapping states at the grain boundaries Nt [3].
Starting from the simulation we notice that effective B diffusivity in the grain boundaries is only about 200 times faster than that in the grains.
The B exchange between grains and grain boundaries becomes the dominating transport mechanism.
The medium number of interstitial-atoms to be trapped in small Si–B and B–B clusters in grains m takes the value of 2; which leads to the best fitting for all the profiles.

The results show that the grain size is affected by the spindle speed.
Increasing the number of passes reduces also the size of the grains and the intermetallic phases in the AZ91 alloy.
The alloy in as-cast condition showed α-grains of about 500µm size and intermetallic phases in different forms at the grain boundaries.
The α-grain size was similar for both rotation speeds, with an average grain size of 6µm.
During process at 900rpm/30mm.min-1 the α-grain size varied from 400nm to 2µm, while the β-intermetallic phase was refined (grain size max. 600nm).

This area is filled with fine columnar grains.
Inside of the Al matrix, a number of dispersoids are distributed as shown in Fig. 3 (b).
In this area, single constituent particles are present along the grain boundaries/cell boundaries as well as inside of grains.
Fig. 4 (c) shows the one on the grain boundaries.
The agglomerated particles are considered to consist of a number of particles.

Aluminum-copper alloys offer both high strength and excellent ductility suitable for a number of automotive applications to reduce vehicle weight; however, the alloys are difficult to cast because of their tendency for hot tearing.
Aluminum-copper 206 alloy has a number of potential applications to reduce vehicle weight, including automotive suspension knuckles, vehicle control arms, differential carrier parts, aerospace and military castings [1].
Image analysis of the samples yields the grain size plot in Fig. 4.
In addition, the SSM samples have finer grain structures.
Grain size of the representative liquid cast and semi-solid cast samples.

Grain Boundary Velocities, v.
Sub-grain Boundary Growth.
The sub-grain mobilities were estimated from the average growth rates of large numbers of sub-grains during more standard annealing experiments outside the SEM.
Grain boundary velocities and mobilities.
ii) Sub-grain mobilities in the same alloys measured during sub-grain growth using a FEG-SEM gave mobilities one or two orders of magnitude lower than the grain boundaries but, quite surprisingly, mobilities close to those of a similar Al-Si alloy.

The grain sizes are about 40μm after anneal.
The number of craters after 5 pulses reaches the top, and then decreases with the increment of pulses.
Generally speaking, material properties mainly depend on a number of factors like grain size, phase composition and residual stress.
Consequently, ultrafine grains were formed on the irradiated surface.
Fig.5 The relation between the microhardness of the surface and the number of pulses Conclusion Many craters are inevitably formed on the irradiated surface, and the densities of distribution of the craters are related to pulsed numbers.