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This kind of material has been used in a number of fields where a high wear resistance is required, namely aeronautics and space industry and automobile industry etc [1-5].
At this temperature, the crystalline grain becomes evenly fine (Figure 1(b)).
Therefore, 1200℃ is the prefect sintering temperature, under which the evenly fine crystalline grain is found, which has most properties of the equiaxed grain.
When the percentage of TiC is 8%, the crystalline grain is evenly fine equiaxed grains with the smooth edge.
At 1200℃, the smallest crystal grain is found and the greatest hardness is found.

Finally SiC grains are surrounded by the formed Si2ON2 grains to forming Si2ON2-SiC ceramic with chemical bond.
This is because it generated more Si2ON2 grains at 1500°C which can bonded with SiC grains better.
The Si2ON2 grains well combined with SiC grains to form a three dimensional net and protect SiC grains not to be oxidized in the air.
Small Si3N4 grains also can be found adherent on Si2ON2 grains.
Small quantity of Si2ON2 grains can be seen in this image and there are large interspaces between SiC grains.

SPD-type processes create relatively a high concentration of lattice defects such as grain boundaries, dislocation and vacancies.
As a result of the high density of grain boundaries and of other lattice defects, hydrogen atoms can quickly penetrate the sample and create the βphase.
Between passes the billet can be rotated around its longitudinal axis which, together with the number of passes, strongly determines the final microstructure.
After applying a high number of rotations an almost homogeneous nanostructure can be obtained.
SPD methods not only achieve nano-sized grains in metals but also create a much higher concentration of lattice defects like dislocations and vacancies compared to standard method of producing nanocrystallinity.

The main research work was directed towards modification of the structure by grain refining.
The microstructure indicated fine petal-like grains of α instead of a coarse dendritic structure were formed.
Detailed review of the grain refinement of Zn-Al alloys is presented in [10].
Fatigue Standard Specimen (dimensions in mm) The fatigue tests were performed on the Wholer fatigue testing machine at different stress levels, and the number of cycles to fail at each stress level was determined.
It was difficult to determine the grain size of ZA5 and its alloys because there were no clear grain boundaries of these alloys.

The sharpening process set the metal bond back and thus the worn and dull diamond grains fell out of the bond and new grains were liberated.
In addition, segmenting the grinding wheel reduces the number of the momentarily engaging cutting edges which increases the uncut chip thickness of each active grain.
Therefore, the number of the momentarily engaging cutting edges is increased at higher depth of cuts.
Additional to an increased uncut chip thickness, increasing feed speed increases the number of the kinematic cutting edges.
Increasing the cutting speed reduces the number of kinematic cutting edges and mean uncut chip thickness of each active grain.

Since the above work a number of systems have been reported [2-6] where low temperature anneals give rise to structural modifications in SiAlON's suggesting that a common process is taking place, which has yet to be fully explained.
The microstructure of the Yb-SiAlON materials consists of generally equiaxed grains of around 1.0µm, which are surrounded by a grain boundary phase.
The grain boundary phase is rich in the rare-earth cation.
Post sintering anneals, change the nature of the grain boundary phase.
Close examination of the grain boundary regions revealed that the grain boundary phase consists of both a crystalline part and some remnant glass phase.

Over the past 10 years at the University was developed a number of technologies to get ferrous and nonferrous metals and alloys with sub-ultrafine grain structure by equal channel angular pressing.
Pressing of the billets were carried out at room temperature of 20°C, which also contributed to obtaining sub-ultrafine grain structure.
For the determination of grain size of the billets, deformed in equal channel step matrix of a new design GOST 5639-82 "Methods for detection and determination of grain size " was used.
Results of determination of grain size Cycle number Initial 1 2 3 4 5 6 7 Grain size, microns 125-88 62-31 31-22 15-12 11-9,8 9,5-7,9 6,7-4,5 3,6-2 According to the results of metallographic investigations is seen that with the passage of each subsequent pressing cycle in equal channel step matrix of a new design there is a significant grain refinement of the material.
But at the same time, in the course of the experiment, after the passage of the billet 7 cycles of deformation, it cannot achieve the grain size of 100 nm.

Coupled with the lubricating of the graphite powder, the wear of CBN grains is little.
Another, the wear of the grinding wheel depends on the amount of wear of the CBN grains.
The number of the elements was 276,860.
During the grinding, the wear mechanism is that the wear mainly occurs at the abrasive coating of CBN grains.
The wear of the grinding wheel depends on the amount of wear of the CBN grains.

The analysis of carbon content should be considered semi-quantitative, due to the fact, that used method does not allow quantitative analysis of elements with low atomic numbers.
Grain size doesn’t change over the cross section of the analyzed sample and is equal to the grain size of sample from set no.1.
Average size of grains is G7.
Set no.3 – non-magnetic material: Microstructure of the sample is formed by austenitic polyhedral grains (grain size G3,5), and sulfur based inclusions.
Finer grains lead to higher content of martensite.

Table 1 Technical parameters of the double row dibbling wheel precise seeder for membrane covering the whole of double furrow planting corn parameter numerical motive power 2.82kw engine speed 3000r/min the weight of the whole machine 155.6kg machine size 1550×650×520mm film size 0.008×1200mm planting spacing 330mm spacing 400mm operating speed 500mm/s seed grains per hole 2 grain sowing depth 30-50mm productivity 0.18hm2/h Dibble wheel working principle Dibble wheels are precision planter of the core components.
Fig. 2 Working cycle diagram Dibble wheel design parameters Dibble wheel radius R of the important parameters and cavitation number of collectors Z.
Dibble wheel radius and roller speed, planting hole spacing, planting depth, cavitation device number and so on.
Considering the various parameters into the formula (1) obtained: Bunch wheel radius R = 352, a point is the number of Z ≈ 10 (1) where Z is the number of cavitation device, R is dibble wheel radius, H is sowing depth, t is sowing hole spacing.
Field test Machinery seeding operation is completed, in accordance with the NY/T987-2006 “Filming mulching machine job quality” standard planter operating performance measurement requirements, calculations corn membrane covering the whole film double furrow planter job hole rate, points grains pass rate, pass rate of sowing depth under the membrane, acupuncture wrong porosity values ​​of the experimental data is shown in Fig. 3.