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The result evidently shows that the ultrasonic-assisted deformation has a meaningful influence on the grain refinement – the application of the USV enhances the formation of deformation bands and new sub-grains.
To date the evolution of microstructure has been the subject of a number of studies focused on cubic and hexagonal materials [11] [12] [13].
It is clearly seen that this shear bands nucleate at the grain boundaries.
The highest degree of grain refinement was observed in the centre of deformed area.
Sklenička, Grain and subgrain boundaries in ultrafine-grained materials, Mater.

A number of offshore structure maintenance method require underwater working.
From the observation of metallographic microstructure underwater welding it appears that phase grains coarser than the microstructure of welding on land.
This can happen because the weld metal suffered liquefaction then freezes so quickly that opportunity grain experiencing severe grain growth during thawing did not get transformed into finer grains, so that the material is harder but brittle.
Weld metal run into liquefaction then freezes so quickly that opportunity grain growth could not be transformed into finer grains due to rapid cooling.
This is due to the austenite grain area owned by the biggest austenite grain.

Through a large number of experiments, n(citric acid):n(ethylene glycol)=2:1, n(citric acid):n(Nb5+)=1.5:1 is the best equipped ratio.
Figure (a)-(e) can be clearly observed that sintering at low temperatures, ceramics has fine grain size and large number of pores.
When T=1100℃℃, grains are well growed, particles are uniform distributed, size is relatively uniform,and density is better.
When sintering temperature reached 1140℃℃,grains melt, which is due to higher sintering temperature.
(a) (b) (c) (e) (d) Figure 2 T=1100℃℃, SEM photographs of 0.992KNN-0.008BF at different PH: (a)1-2 (b)2-3 (c)3-4 (d)4-5 (e)5-6 As can be seen from figure 2 from (a) to (c), quartet blocky grains gradually regularization, pores gradually smaller and fewer, organization densification improved; in photographs (a) and (b), abnormal grains growth in serious and grains have different sizes; the grain size gradually homogenizing and regularization in photographs (c) and (d); particles have good uniformity and density, and the shape is tetragonal blocky structure.

A number of toughening mechanisms, including fine grain, crack deflection and grain pull-out, were observed during microstructural analysis of the composite.
With increasing the TiB2 content, the grain became smaller which might improve both the flexural strength and fracture toughness of the composite as shown in Figs. 2 (c) and (d).
Both the fine grain and the difference in thermal expansion coefficients between the B4C matrix and TiB2 particle could effectively improve the fracture toughness of the composite.
The grain pull-out was observed on the fracture surface of the composite with 43 % TiB2, which proved the fracture toughness improvement of the composite with the increasing TiB2 content.
The increase of toughness was mainly resulted from both the fine grain and the crack deflection caused by the difference in thermal expansion coefficients between the B4C matrix and the TiB2 particle.

Conversely, good ductility in austenite is associated with high grain boundary mobility that produces fine, recrystallised grains and subsequent dimple fracture after plastic tensile stress.
Glodowski, Fine-grained practice – revisited, Proc.
Precipitation sizes were measured and the distributions calculated when particle numbers exceeded 100.
This marked difference in flow behaviour suggests higher austenite grain mobility in Al-free steel F.
Grain boundary sliding (GBS).

After machining, samples of 5x5 mm were sectioned by wire-EDM, then polished and etched for 35 seconds using Kalling’s reagent (number 2) to observe microstructural changes (affected layer and grain size) using a light optical microscope (1000X).
Affected Layer and Grain Size.
The grain size of each machined surface has been measured by optical microscope (1000X), and it was found that in all investigated cases the grain refinement occurs.
Grain size on the bulk material Grain size on the bulk material (a) (b) Figure 6: Grain size evolution from the machined surface to the bulk material (a) different cutting speeds at 0.1 mm/rev as feed rate and for (b) different feed rates at 70 m/min as cutting speed.
According to Herbert et al. [8] different intensity represents different grain size.

of Resources and Environment, Sichuan Agricultural University 46 Xinkang Road, Ya'an 625014, PR China; 2 College of Resources and Environment, Sichuan Agricultural University 46 Xinkang Road, Ya'an 625014, PR China; 3 College of Resources and Environment, Sichuan Agricultural University 46 Xinkang Road, Ya'an 625014, PR China; 4-6 College of Resources and Environment, Sichuan Agricultural University 46 Xinkang Road, Ya'an 625014, PR China; aemail: wanglei198626@163.com , bemail :wuj1962@163.com, cemail: Shuzhen0827@163.com , demail: 16422272 @ qq.com eemail: wl8579086@163.com , femail: 804869246 @ qq.com Keywords: Biogas slurry; wheat; yield; heavy metal content; Abstract: In this paper, throng studying effect of biogas slurry of different fertilizer rates on wheat yield and some biological traits, found that environmental conditions in the purple, biogas slurry application rate was 3500kg/667m2, wheat yield was maximum; And heavy metals Content in wheat grain
Table 4 data showed that the treatment was no significant difference between the grain weight, but plant height and panicle number and grain yield of acres were close (correlation coefficient were significant or highly significant), suggesting that biogas slurry supply adequate nutrient, the proportion of coordination, promoting the growth of crops and form of Spike long, thus wheat get a higher yield, Biogas slurry application rate is too high, but also inhibited the production of wheat. 3.2 Effect Of different treatments on heavy metals content in wheat grain Fig. 1 showed that heavy metals Content in wheat grain would increase with the increasing of biogas slurry application rate; When the slurry application rate was in 1500 ~ 4500kg/666.7m2 (for treatment 5 - treatment 9), Wheat grain Pb, Cd content and conventional chemical fertilizer treatment was not significant (P> 0.05); When the slurry application rate was in 5000kg/666.7m2, Wheat grain Pb, Cd were significantly higher than
Wheat grain Cr content was significantly lower than conventional chemical treatment (P <0.05).When the slurry application rate controled in the range of 1500 ~ 3500kg/666.7m2, compared with conventional chemical treatment, the application of biogas slurry did not cause the increase of heavy metals in wheat grain.
When the slurry application rate was high (≥ 4500 kg/666.7m2), the application of biogas slurry led to the rise of heavy metal content of wheat grain than conventional chemical treatment and mixed fertilizer treatment.But compared to the limits of the “Contaminants in Food”(GB2762-2005), the slurry treatment of wheat grain Pb, Cd, Cr, As, Hg content were lower than the corresponding limits of pollutants (including As, Hg were not detected),showing biogas slurry agricultural would not cause food heavy metal pollution, Wheat planted was in line with food hygiene standards. 4 Conclusions The slurry contains a comprehensive nutrient and rich organic substances, which has the speed slow shrugging characteristics of exploiting, soil improvement.This study suggests that in the dry system, Sichuan neutral purple soil environmental conditions, in the whole growth period, it can supply the nutrients needed for growth of wheat, so as to promote wheat growth and development, and improve the biological
yield and biological Treatments Grain yield (kg/hm2) 1000-grain weight(g) Plant height (cm) spike numbers （ten thousand/hm2） 1（ck1） 4882.67 63.82 100.33 300 2（ck2） 6569.00 61.36 96.83 363 3（ck3） 5731.33 62.90 94.56 341 4（ck4） 7801.00 59.50 97.17 314 5 7357.50 65.02 89.50 292 6 8194.50 63.28 89.00 352 7 7078.00 66.37 87.83 317 8 7312.50 65.67 98.50 283 9 5738.33 64.67 96.67 327 Fig. 1 References [1] Turner XuZhaofei, ZhangHuiye, ZhangDingyi.Wheat Quality and Its Improvement[M],Beijing.

From the figure it can be seen that the platelets S phase coarsened notably in the grain and near the grain boundaries.
On the other hand, they also make the number of holes also increase gradually.
When tension at 200 °C, the number and size of the dimple and void increased with the increase of the test temperature (Figure 4 b5, c5).
According to the above results, when tension at a lower temperature (below 175 ˚C), the finer needle shaped precipitate were presents within the grain and the grain boundary.
The number of the crack initiation locations reduces, while the local deformation increases generally.

The AFM observation shows that the average grain size of LaB6 crystallites is less than 23nm.
Numbers of defects on surface decreased firstly then increased afterward.
Number of defaults is decreased with rising of the substrate temperature.
Average grain size of LaB6 film that deposited at 400℃ is the maximum.
The surface roughness of LaB6 enlarged with grown of grain size.

Austenitic grain pattern is observed with Olympus GX71 optical microscope.
Fig.3 Original austenite grain Fig.4 Austenite (deformation temperation =850℃) Figure 3 and 4 show that at the deformation temperation of 850℃, the grain in deformed structure has a tendency of being stretched compared with the original grain, and a slight amount of dynamic recrystallization grains appear near the triple junction and grain boundary.
Compared with the deformed structures the original grain（Figure 3） and at deformation temperation of 950℃（Figure 5）, grains are obviously refined，the dynamic recrystallization area of the deformed structures at strain rate of 1s-1 expands, and the original grain is gradually replaced by dynamic recrystallization grain with the size of newly generated grain enlarging and the number Fig.5 Austenite (deformation temperation =950℃) of cores decreasing.
The dynamic recrystallization behavior occurs more fully in the deformation organization, and the grain boundaries of the stretched original grains become basically obscure, larger grains of dynamic recrystallization being formed in the boundary zone, and being distributed in a homogeneous manner as shown in Figure 5.
Meanwhile the dynamic recrystallization is not complete under lower deformation temperation with newly generated grains mainly concentrated in the area close to the grain boundary of the stretched original grains, the proportion of which being low and the distribution of which being uneven.