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From the XRD patterns,one can infer that Al and Ti atoms substitute Zn in the hexagonal lattice or probably segregate to the noncrystalline region in grain boundaries.
When the target-substrate distance is 55mm, the film surface is smooth and the grains are also clear , smooth and uniformly stacked up, as shown in Fig.2(a).
As the target-substrate distance is 60mm , the grains like feathers and grow loosely.
It is clearly observed that the films have some rugged and irregular structures on the surface. so no grain boundaries are visibly found, as shown in Fig.2(b) (a) d=55mm, P=100W Fig.2.
This increase indicates that the number of atoms sputtered from the target is proportional to the sputtering power.

The basic principle of SMAT is the repeated multidirectional impacts of accelerate metallic or ceramic spheres at high strain rates onto the surface layer of a bulk metal, resulting in severe plastic deformation with a gradient of grain sizes along the deformation depth [5].
The reduction of grain size is known to have a significant enhancement effect on the mechanical properties of materials [8].
SMAT can induce grain refinement at the nanometer scale in the surface layer of bulk samples by generating the plastic deformation in the top surface layer [6, 11].
The plastic deformation in the surface layer with a large strain and a high strain rate results in a progressive refinement of coarse grains into the nanometre regime.
Due to the high vibration frequency of the system (50 Hz to 20 kHz) applied, the sample surface under treatment will be bombarded repetitively by a large number of balls within a short duration, resulting in a severely plastically deformed sample surface layer.

The second phase particles (or empty) and matrix interface are the main source of the micro crack and have formed a large number of micro-cracks.
The micro cracks didn’t appear in the grain and the twin boundaries, and it suggests that the strength of the grain and the twin boundaries are larger than the second phase particles and matrix interface.
For the grains of different orientation, the deformation and deformation resistance are different.
In the loading process, the most favorable orientation and possible micro-stress concentration grain is bound to slip at first.

The infrared spectrum with a resolution of 8 cm-1 and the scan number of 4 was adopted with a spectral region from 400 to 4000 cm-1.
The coating morphology shown in Fig. 3 further reveals the influence of the melt state on grain size of the coatings.
It is noted that the HA grains located in unmelted part are far larger than those in the unmelted part, which reflects the influence of fast cooling on grain growth during coating formation.
The relatively small grain size located in the resolidified zone, which is around splats' interface, should act as an important factor contributing to mechanical properties.

In this figure, the schematic of the composed anvil type of HPD is detailed in an axial longitudinal section by the numbers: (1) upper part of the anvil; (2) lower part of the anvil; and (3) middle part of the anvil.
Observation by SEM, Fig. 2, of the pure Co electrosintered structure revealed plastically deformed grains as well as voids that might be a consequence of incomplete consolidation.
The grains formed by the original Co particles appear to be flattened in the direction of the applied pressure, Fig. 2, while the grain boundaries expanded in the perpendicular direction.
Electrosintered Co structure with evidence of plastically deformed grains.

The primary β grain boundaries can also be found.
During shot peening, large numbers of dimples were formed in the surface layer.
Therefore, it is believed that the surface layer microstructure evolution was the results of α colony merging with its adjacent one and lamellar grains breaking.
Hodgson, Hossein Beladi, Ultrafine grain formation in a Ti-6Al-4V alloy by thermomechanical processing of a martensitic microstructure, Metall.
Hodgson, Hossein Beladi, Enhanced mechanical response of an ultrafine grained Ti-6Al-4V alloy produced through warm symmetric and asymmetric rolling, Mater.

They help, on one hand, pin the grain boundaries and inhibit the grain growth.
Therefore, HSLA steels are formed with fine grain structure with high toughness.
Transmission electron microscopy (TEM) is a powerful characterisation technique for compositional and structural analysis but there are a number of difficulties.
Kozeschnik, Coupled Grain Growth and Precipitation Modeling in Multi-Phase Systems, Mater.

Based on microstructural observation, the grains on fracture surface revealed preferred orientation.
Thus, XRD analyses were made on sections perpendicular and parallel to the pressing direction to investigate the preferred orientation of grains.
This indicates that the c-axis of the grains is preferentially oriented parallel to the pressing direction.
This small orientation factors was regarded to be caused by insufficient activation energy and time for grain growth and orientation during spark plasma sintering, conducted at relatively low temperatures and in a much shorter sintering time.
However, κel depends on the electrical resistivity, Lorentz number (L0) and temperature (T): κel=L0T/ρ.

The size of Al2O3 grains in the composites varies from 1.4 µm to 1.9 µm, ZrO2 inclusions from 0.3 µm to 0.4 µm and Ni inclusions from 2.3 µm to 4.9 µm.
For example, the size of Al2O3 grains increases from 0.31 µm to 2 µm as the dwell time increases from 1 minute to 5 minutes.
In their report, the length of silicon nitride grain increased to 3 times that of the original dimension within the first 1 minute at the SPS temperature.
The Al2O3 grains after 1 minute at 1350o C remains more or less the same as that of the starting particles.
Acknowledgments The present study was supported by the National Science Council under the contract number of NSC-90-2216-E002-034.

(3) the high diffusivity: since the diffusion rate of nanometer crystal of conventional crystal from 1016 to 1019 times, 100 times that of grain boundary diffusion.
The amorphous alloy jin jing chemical technique make it possible to direct production of a large number of nanocrystalline alloy.
The former Soviet union academy of sciences institute of metal superplastic mechanical heat treatment method, in the pure metal, alloy or intermetallic compounds in super fine organization, material strength and fracture toughness will be improved obviously. 10 microns for example, 1420 alli alloy grain size of the plate, the yield strength of 330 mpa, elongation is 5%, and 200 nm grain size of the same material, the yield strength of 550 mpa, elongation also slightly increased.
Nanomaterials in the field of space and there are many potential applications, for example, between ceramic and metal compounds (such as TiAI Ti3Al, etc.) are usually macroscopic brittle material, when its grain size reaches nanometer level, will become a macro plastic material, can be obviously improved processability, make them are likely to get the application in advance on the shuttle.