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XRD, FESEM and EDS results showed that TiC-TiB2 ceramic coating was composed of fine TiB2 platelets, TiC irregular grains, Cr metallic phase and a few Al2O3 inclusions.
As a result, at initial stage of solidification a number of TiB2 solids as the primary phases precipitate from TiC-TiB2 liquid, follwed by peritectic reaction (TiB2 + Ti → TiB) due to the presence of liquid Ti alloy, finally, a number of ultrafine TiB platelets (diameter of 0.5 to 1.5 μm and length of 2 to 5 μm) come to existence around the joint of ceramic to Ti alloy, resulting in the achievement of the ultralfine-grained microstructure in joint region and the ceramic coating nearby the joint, as shown in Fig. 4(c) and Fig. 6.
The Ti-6Al-4V substrate consists of equiaxed α and intergranular β phases; however, the heat-affected zone of Ti-6Al-4V substrate nearby the joint area shows the presaence of a number of needle-shaped grains, as shown in Fig. 4(c) and Fig. 7.
The maximum microhardness measured 25.8 ± 3.5 GPa at TiC-TiB2 coating, and high hardness of TiC-TiB2 coating is considered to benefit from the achievement of fine-grained microstructure in near-full-density ceramic coating.
The TiC-TiB2 ceramic coating was composed of a number of fine TiB2 platelets, irregular TiC grains and a few of Cr metallic binder and Al2O3 inclusions, and physical, mechanical properites showed the density, relative density, microhardness and fracture toughness of TiC-TiB2 ceramic coating reached 4.20 g · cm-3, 98.5%, 25.8 ± 3.5 GPa and 16.5 ± 2.5 MPa · m0.5, respectively, and high fracture toughness of the ceramic coating benefited mainly from a coupled toughening mechanism of crack deflection, crack bridging and pull-out by fine TiB2 platelets.

Figure 3 shows the primary phase in CA1 are coarse columnar crystals, dendrites developed, large grain size, only a small amount of equiaxed grains distributed in the central part; the most primary dendrites in CA2, CA3, CA4 become small and smaller equiaxed and uniform.
The primary phase in CA4 most obvious grain refinement, are relatively uniform fine.
The CA4 have small dimples larger size, which is the grain boundary interface thicker discontinuous distribution of second phase particles.
Large number of small dimples evenly distributed around a large dimple.
Nano-SiC powders also can be used as heterogeneous nucleation, played the role of crystal nuclei, and increased the number of nuclei, refine nuclear grains of the aluminum bronze role.

Furthermore, research on 3D microstructure simulation with many grains in large-scale is scarcely reported.
In 3D simulation, the homogeneous temperature field assumption was induced for each grain domain.
Fig.3 (c) and (d) shows the multi-grain growth procedure in gradient temperature field.
As the cooling rate increased, the grain size decresed.
(a) (c) Fig.6 3D simulation results of 719 grains (a) grain morphology and distribution, (b) solute distribution Tab.1 2D and 3D calculation time of the simplified CA model Type Cell Number Nucleus Number Computing Time (min) 2D 100×100 12 11 2D 500×500 100 95 3D 100×100×100 50 8 3D 200×200×200 719 70 Summary A simplified CA model was developed for simulating the micrustructures of Mg alloy.

It reveals that the melt spinning gives rise to the obvious broadening of the major diffraction peaks of the alloys, to be ascribed to the refined grain and the stored stress in the grains by melt spinning.
Fig. 3 shows the evolution of the discharge capacities of the Mg20Ni9M1 (M=Cu, Co) alloys with the cycle number.
On the other hand, the refined grain by melt spinning is favourable to the discharge capacity because the grain boundaries possess the distribution of the maximum hydrogen concentrations [7].
Fig. 4 presents the cycle number dependence of the SN values of the Mg20Ni9M1 (M=Cu, Co) alloys.
The enhanced D value by the melt spinning is ascribed to the refinement of the grains of the alloys due to that the huge numbers of the grain boundaries available in the nanocrystalline materials provide easy pathways for hydrogen diffusion and accelerate the hydrogen absorbing/desorbing process.

Fine-grained parallel execution is an elegant way to speed up sequential simulations.
The simulator works strictly as master/worker(s) paradigm for fine-grained parallel and distributed stochastic simulations.
Communication costs are crucial to the performance of a fine-grained parallel and distributed simulation.
The influence of the number of cores used in parallel simulation is investigated.
Miller, "Random number generators: good ones are hard to find," Commun.

When strain rate becomes to 100mm/s, the number of increasing dislocations are more than that of disappeared dislocations, so the saturated value of hardness of pure Cu comes to 178HV5 after only 3 passes.
With the increasing of passes, shear bands disappears and elongated sub-grains appears, then they turn to elongated grains as shown in Fig.2a and 2b. when processing passes exceeds eight, grains turn to equiaxial grains as shown in Fig.2c and 2d.
From the present literatures, high angle grain boundaries can be formed from dynamic recovery but it is one of conditions of ultra-fine grains with high angle grain boundaries but not the mechanism.
It is well known that grain boundary sliding can’t be produced from low angle grain boundaries.
Therefore, the grain boundary sliding mechanism can’t be started before the forming of high angle grain boundaries.

Grain size is shown to have a significant effect on cracking.
They are intergranular by nature and form along the grain boundaries.
Two different grain sizes were used for the CMT work to test the grain size effect, these are 3.5mm and 4.9mm average diameter.
The average grain diameter of the material used in these welds is the 3.5mm size.
It also shows that there is a small effect of grain size, with the larger grain sized material showing more cracking compared to the smaller grain size. 21.82% 2000 2500 3000 3500 4000 4500 5000 5500 100 200 300 400 500 600 700 Small grain size Large grain size ACL (µm) Arc Power (W ) 0.30 0.35 0.40 0.45 0.50 0.55 0.60 100 200 300 400 500 600 700 Small grain size Large grain size ACL (µm) Travel Speed (m/min) 23.64% 34.55% 20.00% a) b) a) b) a) 1 -4 -2 0 2 4 6 8 Difference (mm) Power (kW) Cracking (Before - After) Not cracked - Not cracked Not cracked - Cracked Cracked - Not cracked Cracked - Cracked b) Lowest cracking Highest cracking A small number of the laser samples showed evidence of solidification cracking in the FZ.

Purity and grains size are important for the high purity aluminum target.
The sample numbers together with process parameters are shown in Table 1.
However, there are newly formed recrystallized grains in the center of the sample, which are equiaxed grains.
And the average grain size of the recrystallized grain is about 200 μm.
This makes the cumulative strain in the easy deformation zone to be much bigger than that of the free deformation zone and stagnant zone with the number of forging passes increasing.

The common index was relationship between recovery rate and cold-heating circulation number.
The relationship between recovery rate and cold-heating circulation number of CuAlNi and CuAlNiBe was shown in figure 1.
Fatigue Life Cycle The number of cold-heating circulation of different alloys samples before fatigue fracture was shown in table 3.
Tab3 The number of cold –heating circulation of different alloys sample Alloy CuAlNiBe CuAlNi CuAlBe Single Crystal Polycrystalline Single Crystal Columnar Crystal Polycrystalline Number 487 7 465 237 45 The results in table 3 showed the fatigue life cycles of every kind of single crystal material were more than polycrystalline and columnar crystals obviously.
And the number of cold-heating circulation of CuAlNiBe single crystal was more than other alloys.

Moreover, the grain size distribution is homogeneous, and there is a large amount of low angle grain boundaries (95.6%).
Low angle grain boundaries existed in lamellar structure account for most of the grain boundary, just as the grain boundaries map shown.
The number fraction of 30o-40o<111> boundaries is in fact quite low, and only 10% (length fraction) of these boundaries are found between the cube regions and their immediate surroundings.
Heavier the blue color of grain is, lesser deviation to the ideal cube orientation the grain is.
The color key is the same as in Fig. 1 Fig. 4 (a) Crystal orientation map depicting the spatial distribution of cube grains (heavier the blue color of grain is, lesser deviation to the ideal cube orientation the grain is.) and (b) Distribution of the area fraction of cubic grains vs. tolerance angle.