Search results

workpiece small abrasive grains big abrasive grainsLoad plastic agent semi bonded abrasive plate weight workpiece Fig.1 "Slump" mechanism of semi bonded abrasive plate Fig.2 Schematic diagram of Semi bonded abrasive lapping system In order to improve surface quality of Ge substrate efficiently, one effective strategy is increasing the number of active grains while maintaining processing load, which results in reduction of grits grinding force.
Semi bonded abrasive plate is manufactured of plastic agent, additive and abrasive grains.
Because of plastic agent, the big protruding abrasive grains will slump into plastic agent in processing, as it is shown in Fig.1.
The number of active grains will increase and the grain depth of cut will decrease.

In regions without cracks, grain size was normal and the ferrite was fine and distributed uniformly within the grains.
Such large grain size is much greater than the fine grain size of new solid forming on the mold wall.
In fact, Dippenaar has recently proposed that austenite grain size is influenced by the grain size of pre-existing delta ferrite, which puts blown grain formation at, or just behind the solidification front [6].
The average grain size was 1220±600 microns.
In reality, because of the nucleation barrier for the precipitation, the actual precipitation temperature will be lower and a sudden explosion in number of the precipitates is expected at lower temperature due to a high super saturation condition.

Fig. 4 The mechanical properties analysis of test samples: (a) tensile strength; (b) yield strength; (c) elongation; (d) brinell hardness 3.2 Microstructures Fig.5 shows the optical microscopy test results of 7085 ingot casting, the average grain size is 42μm, the Al2Cu and eutectic phase were distributed nearby the grain boundary.
In the region B, the microstructure is dense and tiny, no large size brittle phase was observed inside the α primary phase, however, numerous micro-shrinkage metallurgical defects were found inside the α primary phase and nearby the grain boundaries in region A, as the blue arrow shows in Fig.5d, 5e and 5f.
The consistency and continuity of the microstructure were damaged by the micro-shrinkage defects, the concentration stress is normal for irrelevance of 4～5 times than the normal tissue, leading to the defects proliferate easily through the grain boundaries.
As shown in Fig.6, some rectangle morphology composite phase distributed nearby the grain boundary were tested by using the EDS analysis, which were verified to be Al3Zr, Al3Ti and Al7V phase, playing the grain refinement role in the solidification process.
In the region B (shown as Fig.7a, 7b, 7c), the fracture crack was transferred by the grain boundaries, a clear inter-granular fracture nature can be observed, the peak value of intense stress was released by the plastic deformation.

. % Gd mostly at the grain boundary regions [8].
It also can be seen that using 1200 grain mesh increases the potential values generally.
Fig. 3: 1200 grain mesh: OCP R10 (top left) and OCP R12 (bottom left).
What is obvious is that, the numbers of cycles to fracture are reduced considerably due to Ringer-Acetate solution.
Pitting corrosion areas act as crack tip during fatigue test and thus strongly reducing the number of cycles to fracture.

The traditional solution to this problem involves carrying out compressive tests on a large number of samples in order to calculate a significant average value, but unfortunately, this value has a wide range of error.
On the other hand, BD2 and BD3 are constituted by clasts (cm-size) surrounded by a fine-grained matrix.
Texture description Crystal size [µm] Porosity [%] Mineralogy BL1 cc Cement-filled fractures 100 < 1 Calcite cm Micrite clasts 5 < 1.5 Calcite BD1 cc Cement–filled fractures 100 < 1 Calcite dd Crystalline clasts (massive) 25 < 1.5 Dolomite cd Crystalline clasts (porous) 20 ≈ 5 Calcite/ Dolomite BD2 dd Crystalline clasts (massive) 30 < 1 Dolomite cd Fine-grained matrix surrounding the clasts (porous) 15 ≈ 7 Calcite/ Dolomite BD3 dd Crystalline clasts (massive) 35 < 1 Dolomite cd Fine-grained matrix surrounding the clasts (porous) 20 ≈ 5 Calcite/ Dolomite Table 2.
According to these results, we can confirm that the stiffness of textures with low porosity (< 10%) depends mainly on the length of grain to grain contacts and on the number of contacts per grain (in agreement with [6]).
Considering the rocks studied in this paper, the most resistant and stiffest samples were those with the lowest content of macro-crystalline calcite cement in veins (in the cases of BL1 and BD1) or the lowest content of fine-grained matrix around clasts (in the cases of BD2 and BD3).

Thus, to objectively determine which model fits the data better, a minimum (or Akaike) information criterion (AIC) was introduced, which is defined as AIC = (−2) log (maximum likelihood) + 2 (number of independently adjusted parameters within a model) [14].
Distribution of �ano-grains.
As shown in Fig. 2, the mean grain size of nano-crystalline TiN decreases with the increase of B contents, and based on the AIC, there is a transition of grain size distributions from the normal to log-normal functions.
The real tests showed that the grain-size distribution conforms to a log-normal function when hardness approaches a maximum value.
The recent studies have shown that the log-normal nano-grain size distribution is due to the heterogeneity or polydispersity, such as fluctuations of mean grain sizes arising from a diffusion-drift process [23,24].

And the grain size was 175.3µm.
The numbers against the contours indicate the efficiency values expressed in percent.
As shown in Fig. 4(a), the microstructure show equiaxed grain, fine grain sizes, uniform grain distribution and smooth grain boundaries, which belongs to the typical dynamic recrystallization.
The microstructure show equiaxed grain.
As shown in Fig. 6(a), the microstructure of the deformed specimens exhibits non-uniform grain structure, i.e. mixed grain.

The results show that a large number of coal inorganic electrolyte flocculant and organic macromolecule flocculant will lead to environment pollution and harming people’s health.
Flow of coal slurry contains the most fine and the most difficult to deal with minuteness grains (grain size is less than 0.05mm).
Those grains is hardest to deal with by using general sedimentation or reclaiming or dehydration equipment for fine grain size and high ash content make high viscosity of flow of slurry and difficult to settle and clarify.
But it has special flocculating effect for electronegative fine grain like mud or sand, etc

Findings show that the main causes of stress corrosion and pitting corrosion are uneven microstructure on the work roll surface and a large number of dislocation accumulations, which form microscopic cells.
In Fig. 5 (a), clear intergranular precipitation can be seen at the grain boundaries.
Due to precipitation along the austenite grain boundary, network structures of carbide are formed, which deteriorate the strength and toughness of grain boundaries.
Furthermore, thick precipitates are dominantly grain boundary precipitates, which provide good foundation for the formation of intergranular corrosion.
It can be observed from TEM micrographs of rolls that there is a large number of martensite (Fig. 6(a)) and high density dislocation substructure in wear samples (Fig. 6(b)).

The average grain sizes increased from 0.90 to 6.44 µm with the increase of sintering temperatures from 1100 to 1200 oC.
For the powders calcined at below 800 oC, X-ray peaks of precursors and impurities, TiO, TiO2, BaCO3, PbO and PbO2, appeared, while the high purity of the tetragonal perovskite phase was discovered in powders calcined above 800 oC, which could be matched with JCPDS file numbers 060452 [11].
Grain size expanded with the increase of sintering temperature as expected.
The mean grain size was discovered to be about 0.90, 3.05, 6.44 and 5.71 µm for the samples sintered at 1100, 1150, 1200 and 1225 oC for 2 h.
The resulting (Pb0.925Ba0.075)TiO3 ceramics consist of a variety of (a) (b) agglomerated grain sizes, depending on the sintering temperatures.