Search results

Additive manufacturing brings fundamentally new approach, as the number of technological stages reduces to minimum [5].
On samples also visible grain structure, talking about heterophase of the deposition process: with proper selection of technological parameters some particles partially melted, the fines likely completely melted.
According to the results of determining the chemical composition of the selection area, gray area - γ-solid solution based on nickel, white grid along the grain boundaries - carbides of niobium and molybdenum, black rounded inclusions of oxides of silicon, aluminum and manganese [14, 15], which size does not exceed 1 microns.
It should be noted fine grained facets in samples without heat treatment are occurred.
Samples after heat treatment also have a large number of facets with traces of plastic deformation, which also show the viscous nature of the fracture.

A clay suitable for building constructions consists from three main components: sand (grain size 0.06-2 mm), dust particles (grain size 0.002-0.06 mm) and clays (grain size smaller than 0.002 mm).
Set Clay Sand/clay ratio Water/clay ratio Number of test bodies [MPa] SI Illite, kaolinite 75/25 0.37 6 0.72 SII Illite, kaolinite 80/20 0.37 6 0.70 SIII Illite, kaolinite 85/15 0.37 6 0.41 The tensile bending strength dependence on an amount of a clay was determined.
Set Clay Sand/clay ratio Water/clay ratio Number of test bodies [MPa] SI Illite, kaolinite 75/25 0.37 6 0.72 SIV Illite, kaolinite 75/25 0.295 6 0.84 SV Illite, kaolinite 75/25 0.335 6 0.73 The tensile bending strength dependence on an amount of a mixture water was measured.

The mechanisms of such reinforcement are the strengthening of particles and the strengthening of grain dispersion [13, 14].
It has been discovered that the corrosion process occurs along grain boundaries [20].
The long boundaries of the grains in the pure Ni coating are suitable paths for corrosion, but in the Ni-Cr2O3 composite coating, the grain boundaries are less straight than the pure Ni.
Above 50 g/L, we observe an increase of the areas of grain boundaries and then decrease in the corrosion resistance [20].
As regards the grain size for the composite deposits obtained, it can be seen that it is influenced by the concentration of Cr2O3 nano-particles.

It is show from Fig. 2(a) that the microstructure of deposition area of titanium is acicular α-Ti and linear α-Ti and coarse grain.
The effect of fine grain strengthening on the plastic toughness of pure vanadium deposited area has a certain contribution to improve the overall performance of the weld.
The grain of a phase is fine and showing the characteristics of equiaxed crystal, and there is a grayish B precipitation along the grain boundary showing the island shape.
The microstructure of Fig. 2(c) is vanadium-based solid solution + grain boundary solid solution copper, and the light gray solid solution copper is precipitated as an island chain along the grain boundary of gray-white vanadium-based solid solution.
Therefore, there is flocculent solid solution vanadium in the deposition area of copper, and the presence of grain boundary solid solution copper is present in the weld region of vanadium.

Due to a large number of the optimization parameters and variables the practical solution for rolling is difficult.
Fitting the model of independence reduces the number of degrees of freedom by p = r + c − 1.
The number of degrees of freedom is equal to the number of cells rc, minus the reduction in degrees of freedom, p, which reduces to (r − 1)(c − 1).
The FEM model outputs are the end temperature of rolling (T6P) and the average grain size (Dγ6P) after the last (sixth) pass of rolling [1].
To acquire knowledge about the most important influence on the temperature of rolling (T6P) and the average grain size (Dγ6P), the algorithm of C&RT was used.

There has been large number of studies dealing with fatigue damage behavior of aluminum alloys on various environments.
In addition, an equilibrium phase and precipitate free zone (PFZ) can also be seen in the grain boundaries.
In conclusion, the alloy possesses tabular grain microstructures that are partially recrystallized along the RD.
As for the grain boundary, an equilibrium Al2CuMg phase (S) and a PFZ are found.
Fig. 4 The TEM images of the microstructure of the 2124 alloy plate showing (a) the grain structure, (b) the precipitation phase in grain S’ and (c) the precipitation phase in the grain boundary and PFZ.

Creep mainly depends on the grain size and the temperature.
It has been demonstrated that in ceramic material, due to the low number of activated slip systems, creep is mainly governed by diffusion at intermediate temperatures [6-8].
Therefore, this kind of behavior has been associated to an activation of diffusion-creep in the ceramic chromia film, either at grain boundaries or in the bulk [12].
In addition, recent results report the activation of grain boundary sliding as a companion mechanism of diffusion-creep in this system [13].
Then beyond this moment, the width becomes about constant, which implies that the grain size should evolve more slowly.

This allows, with the same electron beam power, the deposition of coatings with a required content of the fine-grained refractory component.
The binder is chaotically hardened by fine-grained (≤1 µm) compounds of titanium borides of other stoichiometry (Fig. 1,c).
The FeB formation is evidently caused by the fact that with distance from the coating – substrate interface and increasing number of passes the melt temperature grows and the degree of its saturation with boron also increases owing to a more complete dissolution of initial FeB powder particles.
The high wear resistance of coating 2 (KW = 5.72) is evidently due to the regular structure and very fine grain size of eutectic components of the metal binder.
They have the most heterogeneous structure with low metal binder microhardness (Нm = 4–5 GPa), in which X-ray spectrum microanalysis revealed numerous regions of iron free from fine-grained particles.

Dispersed carbides and oxides are distributed along the grain boundaries, thereby strengthening the grain boundary and refining grains [5, 15, 16].
Experimental Commercial W powders with grain diameter of 1.0 µm to 1.3 µm (Xiamen Golden Egret Special Alloy Co., Ltd., Xiamen, China) and Lu2O3 with grain diameter of 70 nm to 90 nm (Shanghai Chao Wei Nanometer Co., Shanghai, China) were used as raw materials.
Catalytic capacity is expressed by the magnitude of activity, which involves the number of surface defects (i.e., surface atoms or atomic groups with unsaturated coordination at the edge, step, or edge of the adsorbate island).
The growth of W grains was inhibited during sintering, thereby enhancing microhardness and bending strength.

Mineral mass fractions % (1)* hematite [Fe2O3] 72.89 (2) kaolinite [Al2Si2O5(Oh)4] 4.64 (3) quartz [SiO2] 12.05 (4) gibbsite [Al(Oh)3] 3.18 (5) goethite [FeO(Oh)] 7.25 (*) Numbers indicated in previous Fig. 1.
This thermal stress causes micro fracture along the grain boundaries of mineral as a result the iron ore sample becomes more favorable for grinding.
The Fig. 3 shows the quantification of the mass of the bolt particle size of 0.5 mm grain size treated with microwave energy.
The Fig. 5 shows the quantification of the mass of the through-size particles of grain size 2.38 mm treated with microwave energy and for particles not treated with microwave energy.
Thus it is possible to highlight the following points: · Fractures generated in the iron ore particles promote increased yield of comminution process due to the reduction in grain size for values close to the original ones.