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The much shorter sintering time can suppress the volatilization of Bi and decrease the number of oxygen vacancy.
It can be seen from fig.2(b) and (c) that the grain sizes of the cool high temperature treatment samples are obviously decrease.
The average grain diameter of BFST is 0.4µm from Fig.2(a).
In Fig.2(e) and (f), the high pressure sintered samples have larger grain size of 1.8µm and improved density with less holes.
The SEM picture shows that the high pressure sintered samples have larger grain size of 1.8µm and improved density with less holes.

A large number of research shows that the addition of rare metal promotes the formation of amorphous phase and stabilizes the amorphous phase [7-11].
When isothermal annealed at 325˚C(between the first and the second peak in Fig.4), the initial crystallization of the amorphous alloy occurs through the precipitation of α-Al phase, which diffraction peaks become sharper after isothermal annealed at 380˚C(between the second and the third peak in Fig.4), it means grain growth of α-Al.
After isothermal annealed at 620˚C and 630˚C(between the third and the fourth peak in Fig.4), diffraction peaks of α-Al sharpen more, which indicates continuous grain growth of α-Al.
As a result, the amorphous aluminum ribbons can not experience too high temperature during subsequent process to avoid grain growth of nanoscale α-Al particles.
As a result, the amorphous aluminum ribbons can not experience too high temperature during subsequent process to avoid grain growth of nanoscale α-Al particles.

.% C O Ni 380 0C 59 8 33 650 0C 45 1 54 From SEM micrograph (Fig.2.a) for carburized specimens at 3800C we observed that carbon atoms were diffused through grain boundaries into the Ni matrix.
Ni matrix is known to react with the C in the solid phase in order to form the unstable Ni3C below 4000C and to intrus C in the grain boundaries [14-16].
The excess of carbon that could not being diffused additionally was distributed as a thin graphite layer around the grain boundaries of Ni particles [16].
At about 4000C carbon atoms had the tendency to diffuse through the grain boundaries of Ni matrix, while at temperatures approximately to 6500C the formation of thin graphite layers was revealed.
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The sub-layer beneath it is constructed by re-crystallized columnar grains perpendicular to the contact surface.
Oval shaped holes scattered along the boundary between these columnar grains and the inner equiaxed grains, which were formed by gas eruption processes.
Micro-cracks zigzag stretched in the surface layer, some of them even penetrated through the entire columnar grain layer and pierced into the matrix below.
From the Fig. 2 e) and f) for CJ20-630 contactor, the contact surface is covered with cooled melting metal drips sputtered outside and there are a large number of cavities in the surface layer.

When alloy of the composition corresponding to the solid vertical line C is cast at the temperature TM (Fig. 4), the resulting microstructure consists of equiaxed grains ranging between 50 and 200 µm.
In addition to cooling rate, grain size depends on the composition becoming smaller with decreasing aluminium content and with additions of vanadium, manganese and chromium [8].
However, in the case of this work it seems that the slow cooling rate during solidification was a predominant factor resulting in rather coarse grains.
Although a number of experiments was performed applying variations of pouring temperature and preheating temperature of the ceramic shell, the appearance of some porosity could not be avoided (P in Fig. 5a).
Microstructures of Ti-48Al-1V alloy in the as-cast condition. equiaxed grains (a); alternate layers of � and �2 lamellae (b).

Compaction to reduce the distance between the particles, the initial strength of cement main causes of soil and this process is also within the cement to provide effective physical and chemical condition. 3 Analysis of microstructure of Cement improved loess 3.1 analyses of intact loess and cement loess microstructure Rich in pore is an important characteristic of loess, has significant effects on the engineering properties of loess, while the degree of development of pores with particle component has a close relationship: If the soil clay content is low, showing a single grain, and its main point contact , the large pores, poor engineering properties of soil; if the clay content is high, it is easy to form a cluster of tablets, set between the cement grains are generally coagulation floc structure is relatively stable and good engineering properties.
Loess under SEM microstructure can be divided into three parts: grain, cement and pore.
Fig.3 SEM photograph of undisturbed loess On the SEM images of 400 magnification were analyzed, from the SEM image can be seen (1 ~ 4), the natural loess, grain clarity, had regular shape, intergranular cement rarely, pores are abundant.
Fig.6 Cement-loess pore microstructure and measurement results Left: Four types of pore area of undisturbed loess in the percentage of the total pore area Right: Four types of pore area of loess cement in the percentage of the total pore area Fig.7 The percentage of various pore area of ​​the total pore area As it can be seen from Figure 7, large hole occupies 50% in the loess area, after the addition of cement, it decreased to around 38%, respectively, in the cement-loess for micro-, small-, medium bore contributed, 4.6%, and 16.44%, which makes cement-loess is more stable, increases its shear strength. 3.3 Microstructure analysis of shear strength indexes of loess cement Add cement to the loess, reshape their micro-structures, a large pore becomes more and more pore size and pore size is smaller than original, the pore from big to small, from less to more, thus forming a reduction of porosity, pore size decreases, the average pore diameter decreases and increases the number

Large amount of submicroscopic defects at the scale of atoms, crystal lattices and grains have a major impact on materials properties.
The weld joint has overall unsatisfactory quality due to presence of high number of defects in or around the weld.
Metallographic analysis documented other defects like almost non-existent diffusion zone, high amount of pores, lack of fusion, and coarse grain in the HAZ (Fig. 6c-f). 3 2 44 55 1 1 2 a Weld joint overview b The root of weld c Coarse grain in HAZ 3 44 52 d Coarse grain in HAZ e Lack of fusion f High amount of pores Fig. 6 Overview of weld joint and the most common types of defects in the microstructure Linear EDX analysis equipped on the electron scanning microscope shows oxidation and contamination near the cavity under the weld root (Fig. 7) in case of second sample.

SEM micrograph of the film shows densely packed fine grains of submicron size, which indicates low film density and poor connection between the grains, this leads to the poor superconducting properties of these film.
Bigger spherical particulates with sizes 1 and 2 μm are, typically, finely grained.
SEM analysis also showed that the annealed films were rough and polycrystalline, with large numbers of microcrystals forming plate-like structures.
The films annealed at higher temperature had large grains compared to the films annealed in low temperature. 10 µm 10 µm (a) (b) Figure 1.

The fine grain sizes and the good interfacial adhesion of the layers impart creep resistance and ductility simultaneously to the laminates [9].
The composite sintered at 1550°C has a fine grain size.
Mean grain sizes are 200nm and 0.8μm, respectively for the 3Y-TZP and Al2O3 layers.
Grain sizes are fine and little cavities appear after deep drawing at 1500°C, as shown in Fig.6.
Acknowledgements This work was supported by Development Program for Outstanding Young Teachers in Harbin Institute of Technology and the National Natural Science Foundation of China under grant number 50575049.

All the alloys contained β phase, although a limited number of diffraction peaks from β phase were seen in Fig.1.
Each micrograph showed equiaxed grains of β phase, and they are in good agreement with the XRD results.
The grain sizes were 249, 261, 270 and 207µm for 7Cr, 5Cr-2Mn, 2Cr-5Mn and 7Mn, respectively.
The grain size was not largely affected by Mn content.
All the Ti-7(Cr, Mn)-3Sn alloys were identified to be β alloys with equiaxed β grains, and β+ω two phases were recognized for 7Mn. 2.