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The mechanism of grain destruction by impact depends on the grain crystal structure.
The greatest changes in the grain composition were discovered in Sample 3: the total number of grains on the 200 and 250 μm sieves increased to 85%, the number of coarse grains on the 315 μm sieve decreased by 9%.
Table 3 data show that the abrasive paper made with normal electrocorundum grain heat treated at 1000°C in nitrogen atmosphere and subsequently air-cooled (Sample 1) have the best results in cutting performance, total metal removal and the number of grinding cycles up to the wear criterion compared to the mass-produced grain in Sample 4.
The effect of oxidizing atmosphere and thermal shock on the grain in Sample 3 allowed to increase the total metal removal figures by 37.8% and the number of grinding cycles achieved practically doubled.
When the grain of normal electrocorundum is heated in an oxidizing atmosphere to a temperature of 1000°C, followed by rapid cooling in water, a qualitative change in the properties of the grain takes place, which increases the performance characteristics of the abrasive paper: the increase in metal removal and the increase in the number of grinding cycles.

Fine grained mortar (FGM) offers a new innovative technology binder system.
The innovative technique is achieved by using a small maximum grain size of 600µm for the mortars.
Studies of the used of FA as a cement replacement in FGM have been reported by a number of researches [14-21].
Fine Grained Mortar The speciality of FGM as compared to commonly used mortar is a mortar containing fine sand with maximum grain size 600 mm.
Then were ground by grinder with 1-3% retained on sieve number 325 (45µm) complying the requirement of ASTM C618.

As the increase of the interval time, the number of grain nucleation increases significantly.
When the interval time is 30s, the grain number of static recrystallization with high accumulative deformation degree is more than that of low degree.
When the hot deformation temperature is 950℃, the grain number of static recrystallization is small, and most of them are dynamic recrystallization grain, and static recrystallization grain with small size only appear near large-angle boundaries.
When the hot deformation temperature is 1050℃, the number of static recrystallization increases sharply, and the fine and uniform grains with a size of 51.53μm are obtained.
As a result, the spread rate of grain boundary increases rapidly and static recrystallization is completed quickly. 2) When the temperature and holding time are the fixed value, a larger deformation degree, which means a larger driving forces of static recrystallization, results in a larger rate of static recrystallization. 3) When the temperature and deformation degree are the fixed value, with the increase of the holding time between passes, the number of grain nucleation increases significantly and the grain size becomes large.

After the number of new grains in each time step is calculated, the location of these new grains is chosen randomly among the remaining liquid cells.
The grain number over the whole section could be measured.
As shown in table 2, grain number in a unit volume, Nv, was calculated from experimentally determined grain number in a unit area, NA, using Owadano's equation: 1/2 3/2 ( ) ( ) 6 v A N N π α= (12) where α=1.2 is a coefficient determined by material properties.
(a) Surface average grain size (b) Center average grain size Fig.9 Comparison of average grain size between experimental results and simulation results at the surface and the center of the three steps under different initial die temperatures Conclusions 1.
With the increase of initial die temperature, the grain size becomes larger.

If the sample, of which the deformation strain is 2%, are taken to be observed, a large number of dislocations can be founded in the grain interior due to the occurred deformation(Fig. 1 (a)), and apparent dislocation networks can also be found in some regions(Fig. 1 (b)).
The trend of polygon is very obvious in the local area (Fig. 1 (e)), while in other regions, sub-grain boundaries began to dissociate, which is the start of sub-grain polymerization mechanism.
The arrow of the figure1(g) shows that after the sub-grain boundaries are completely dissociated, the sub-grain A and B that is merged, and it continues to grow up here by recrystallization.
It is shown from figure1 (h) that the dislocation density inside grains becomes high.
Acknowledgments The authors would like to acknowledge the financial support of the National Natural Science Foundation of China under granted number 50974063 and Jiangxi Provincial Education Department program under granted number GJJ09228.

Figures 2 shows SEM images of the surface of the fine-grained diamond film and the coarse-grained film on the market.
Fine-grained diamond Substrate (cemented carbide) coarse-grained diamond Rmax(µ㨙) Film Structure.
(a)fine-grained one (b)coarse-grained one 100nm 100nm D-band G-band evenness of the fine-grained diamond film in comparison to the commercial product, and excellent adhesion resistance.
The processing accuracy remained high even after 1,000,000 shots, and it was not necessary to remove solder at any time during this number of shots.
fine-grained diamond coarse-grained diamond Rmax(Ǵm) Figure 9: The machining surface roughness of the diamond coated tools.

Residual stresses of first order, type 1 stress or macrostresses, are homogeneous over a large number of grains and a balance of forces is assumed over a large number of crystals.
The number of indexed grains found per location is also given.
Each diffracted grain was characterized by an orientation matrix U j and the minimum number of reflections chosen for indexing each grain was 10.
As the minimum number of (hkl)'s defined to index the grains was 10, this system of equations is overdetermined.
As it is observed on Fig. 4, the individual grain stress level varies substantially from grain to grain and may cause fluctuation of the averaged macrostresses analyzed from a polycrystalline irradiated area

This paper considers the oxidation of a number of nickel containing Fe based alloys of varying compositions, including stainless steel.
This makes the structure of the scale more complex as the number of phases present increases.
Although this Ni seems to be segregated to grain boundary regions, closer examination (Fig. 3) revealed that the Ni is located in regions adjacent to the grain boundaries.
It was found that, as expected, the internal oxide is situated at the high angle grain boundaries and not the twin boundaries, which are clearly visible within the grains shown in the IQ map.
Iron from the substrate below the nickel-enriched layer and in the area surrounding the grain boundary will diffuse outwards preferentially along grain boundaries where it will meet inwardly diffusing oxygen.

Meanwhile, the Nd-rich grain boundary phase was precipitated at the grain boundary of the main phase to form a distinct phase separated from the main magnetic phase.
Materials and methods The sintered cylinder of Nd-Fe-B permanent magnet with the serial number of N38SH and the size of Φ10mm×8mm was used in this study.
So the main phase grains are more thoroughly isolated from each other.
In this work, the domain wall pinning effect was enhanced in the two aging treated samples, in which a large number of the thinner and more continuous Nd-rich phase formed along the grain boundaries, so as to significantly increase the intrinsic coercive force. 4.
Acknowledgments This work was supported by the national major special project for the rare earth and rare metallic materials with the project approval document number: (2012) 1743.

It enables to distribute uniformly the total working contact along the abrasive tool and owing to that, a greater number of active grains is involved in stock removal, which corresponds the value of the effective working contact.
Abrasive grains were fixed using the binder of glasscrystalline structure (Fig.3).
bonding bridge abrasive grain bonding bridge Figure 3.
Microstructure of bonding bridges fixing the abrasive grains.
The microcrystalline structure of abrasive grains, with particles not exceeding 0.1 µm, under such conditions makes it possible to produce a large number of active tool points on the working surface of grinding wheel, which causes the power consumption to remain on the almost constant level.