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In order to observe easily, two flank side of box is made of organic glass. ② is the sand grains.
Table 1: Physical Parameters of Model Experiment Materials and Experiment Design Order Number Grain Diameter （mm） Particle Shape Apparent Density(kg/m3) Internal Friction Angleφ(°) Filling Height（cm） Compaction 1 5～10 Crushed Rock 2733 39.94 50 0.80 2 10～20 Crushed Rock 2731 43.16 50 0.80 3 10～30 Crushed Rock 2731 44.19 50 0.80 4 20～40 Crushed Rock 2727 45.94 50 0.80 5 40～60 Crushed Rock 2729 46.63 50 0.80 6 10～20 Pebble 2627 39.96 50 0.80 7 20～40 Pebble 2633 42.38 50 0.80 8 40～60 Pebble 2631 43.63 50 0.80 Figure 8.
The Volume of Granular at Limit Loose State In order to find out the effected factors of the secondary loose coefficient, the relationships of grain diameter of crushed rock, grain figure of gravel with it were analyzed.
As it shows, the secondary loose coefficient increased with grain diameter of crushed rock.
(3) The secondary loose coefficient increases with grain diameter of crushed rock and pebble, and the secondary loose coefficient of crushed rock is always higher than that of pebble at same grain diameter.

Grain Size and Adhesion Strength of the V8C7 Coatings Produced In Situ Xin Wang1, Lisheng Zhong1*, Xi Zhang1, Yunhua Xu1,2, Hong Wu2, Yonghong Fu2 1School of Materials Science and Engnieering, Xi’an University of Technology, Xi’an 710048, China; 2Shaanxi Key Laboratory of Nano Materials and Technology, Xi’an 710055, China *zhonglisheng@xaut.edu.cn Keyword: In situ, V8C7 coating, Grain size, Adhesion strength.
The grain size of NbC is 350 nm on average.
Due to the microstructure by ultrafine-grained NbC, the hardness and elastic modulus of the coating are 21.1 GPa and 376.1 GPa, respectively.
When loaded to 70N, as shown in Fig. 6 (c), the number of lateral cracks on the bottom of the scratch obviously increased, and there are some cracks running through the bottom of the scratch.
As the number of cracks increases, the number of broken holes increases, the width of particle breakage area at the scratch edge increases.

Austenite grain size about 1µm was reported.
These two phenomena are directly controlled by the number of nucleation sites.
Additionally, it was observed that coarse-grained IF steel (IF1) was deformed inhomogeneously while fine-grained specimens have been deformed smoothly.
Typical IF steel represents coarse-grained structure.
Weng (Ed.), Ultra-Fine Grained Steels.

Grain size non-uniform, eutectic product along the grain boundaries or dendrite boundary discontinuous distribution with the crystal with black second phase particles precipitated by SEM and EDS spectrum scanning analysis shows ZK80 Mg alloy lamellar structures and granular middle mainly MgZn and MgZn2, as show in Fig. 3, the base body is relatively clean and coarse grains, about 70μm.
It can be seen from Fig.2 (b) that significant strip microstructure take place during extrusion process, and significantly elongated along the extrusion direction, at the same time, there are lots of needle shape twin organization and a small amount of secondary twin, part of the twinning occurred kink, coarse grains, the grain size of about 23μm；deformation at higher temperature, due to the low magnesium fault energy, sensitive to deformation temperature [7], the center of the extruded perform billets shows obvious dynamic re-crystallization(DRX) microstructure, and coarse dentrite is replaced by finer equiaxed grain with average size of 5.3 μm, part of the dynamic re-crystallization grain inclusions between serious deformation of grain.
According to Hall-Petch equation (), which is the yield stress, is of single crystal yield stress, K is a constant, d is grain size, strength of alloy increase with the decrease of the grain size, so the grain size larger influence on the strength of the magnesium and its alloys[8].
As can be seen from Fig.2(b) that there are lots of twins in extrusion ZK80 magnesium alloy, and extrusion preformed billets center for isometric obviously, the each grain internal possible slip band and twin belt and there are grain boundary and grain orientation to different between adjacent grain during die forging forming process，because of three to stress, the mechanical properties of ZK80 Mg alloy is improved obviously due to substructure change, twin microstructure disappear and obvious dynamic re-crystallization occurs, grain are refined greatly, the dislocation density increase under die-forging forming.
Grain-boundary sliding in AZ31 magnesium alloys at room temperature to 523 K[J].

Fig. 2 Grain boundary defect model for (Gd,Co,Nb)-doped SnO2 varistors.
Breakdown electrical field of varistors can be expressed by the following equation [7]: EB =n • Vg, (2) where n is the average grain number per unit length, Vg, the breakdown voltage of a grain boundary.
It is found that the resistance of grain boundaries decreases significantly with increasing Gd2O3 concentration.
All the above results and analyses indicate that the average grain size plays a very important role in the variation of electrical properties and Gd2O3 concentration is the substantial reason for the variation of average grain size.
It is not clear how CoGd2O4 inhibits the SnO2 grain growth up to now and this problem needs to be further studied.

As illustrated in Fig.1(b), the size of the core layer grains was about 200μm and these grains were almost equiaxed ones.
However, a small number of core layer grains were still at the elongated state because the silicon content of the core layer was high and the full recrystallization energy was not enough.
These stripes were similar to sub-grains and the grain boundarys were shallow and blurred.
In Fig.2(f), a large number of holes could be seen from the microstructure of furnace-cooled composite plates’ core layer, which implied that silicon loss was severe during the slow cooling in high temperature.
The core layer grains grew up sufficiently.

When rolling in the unrecrystallized zone, a large number of defects such as sub-grain boundaries, dislocations, and deformation bands are formed in the material.
These defects can become ferrite nucleation points, which greatly increases the number of ferrite nucleation and suppresses the growth of grains, to realize the grain refinement strengthening.
Through continuous large deformation at high temperature and strain accumulation, hardened austenite containing a large number of "defects" such as grain boundaries, sub-grain boundaries, and dislocations is obtained.
In order to reduce the interfacial energy by reducing the grain boundary area, the flat ferrite grains formed by rolling deformation have a tendency of spontaneous transformation to equiaxed grains.The total grain boundary area of the web sample is larger than that of the flange and R angle ,because the web is flat and its grain size is smaller than that of the flange and R angle sample.
Since the macroscopic plastic deformation of flat grains is slightly smaller than that of equiaxed grains of the same size, the average impact energy at the flange is slightly higher than that of the web, while the grain size at the R angle is larger, and due to the different rolling directions, there are obvious mixed crystals, the distribution of instantaneous deformation is not uniform, the large-size grains yield preferentially, while the small-size grains have not rotated yet, and the strain difference between the two sides of the grain boundary has increased significantly, which is most obvious at the three grain boundaries.

Crystal grain size and shape were evaluated by optical microscope.
The sheets were consists of equiaxial crystal grains.
Average grain size of 1, 2 and 3 ADB cycles was 20 mm, which is too large to induce a grain boundary sliding.
Tensile strength increased with increasing the ADB cycle number.
Vol. 210 (2010), p.751. ] due to fine crystal grain structure.

In a micro metal forming process, it is possible that only a small number of grains are directly involved.
Experiments Grain Size.
Grains clearly deformed near the inner surface of the cups.
Fig. 8 shows the load increased as grain size decreased.
Fig. 8 Effects of punch speed and grain size on load References [1] M.

The nanohardness of Co binder was approximately 10 GPa and that of WC grains varied between 25 and 50 GPa, depending on the grain orientation and load.
A number of studies have been devoted in the past to the characterization of the effect of microstructure of WC – Co systems on their hardness and the effect of crystallographic orientation of WC single crystals on hardness [2 - 3].
A decrease in hardness with the load increase was found in all indented WC grains.
The nanohardness of Co was approximately 10 GPa and the hardness values of WC grains were in interval from approximately 25 GPa to 50 GPa depending on the orientation of grains.
The EBSD analysis Fig. 3, revealed that the triangle shaped WC grains are close the the basal and the square shaped WC grains to prismatic orientation, respectively.