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When the solution treatment temperature was up to 1200°C, the carbide dissolution completed, grain boundaries became straight, and the grains grew obviously.
For the effect of solution treatment temperature on mechanical properties of Cr20Ni32AlTi there are two main factors: the degree of recrystallization and the number and the distribution of carbides.
In the solution treatment process, recovery and recrystallization caused by grain boundary migration, while grain boundary migration caused by mutual annexation, thus grain growth occurs.
Meanwhile grain size is fine.
Grain refinement also increases the strength of alloy.

The addition of MWCNTs developed grain refinement by the FSP and grain size less than 500 nm was obtained [8].It has been clearly indicated that FSP reduces the grain size and increases the hardness value in MMCs [9-14].
It is revealed from Fig. 3b and 3c that, grain size of the specimens FSPed with SiC particles is remarkably smaller than grain size of base metal.
While the grain size of base metal was 40 µm.
As mentioned earlier, SC tool pine profile resulted in good separation of SiC particles and consequently increases the number of the SiC particles in SZ.
This is because of higher number of hard SiC particles acting as obstacle caused by good dispersion; this leads to higher resistance of surfaces against the sliding.

The stored energy and the grain boundary energy are assigned to each cell.
During a time increment inct the grain boundary moves along a distance d.
This condition determines the number of CA steps and the value of the time increment.
Because of the mobility law (equation 9), preferentially in the neighboring grains rather than in the parent grain After one recrystallization step, the material is partially recrystallized.
In the recrystallized grains, the dislocation density increased 0 500 1000 1500 2000 2500 3000 3500 0,00E+00 5,00E+13 1,00E+14 Number of cells Dislocation density (m 1st Deformation step 2nd Deformation step xperimental curve temperature and for the two phases, the interaction matrix is assumed weak, which means that dislocations can easily pass through the obstacles corresponding to the latent dislocations.

Optical microscopy was used to characterize the morphology of the aluminum grains, the dispersion of SWCNT and present pores in the samples.
The results indicated that the density and hardness of the samples are increased with the increase in the number of extrusion passes and the use of back pressure.
The factors investigated were: the presence of CNT; the number of extrusion passes; the extrusion route used between passes; and the use of back pressure.
The ECAE passes in route A of the sample promoted the alignment of aluminum grains and CNT clusters in the direction of extrusion.
The refinement of CNT clusters occurred similarly to the grain refinement.

The content of Cr, the hard phase generated element, at the grain boundary, is higher than that of grain inside and many hard phases were generated at the grain boundary.
The increase in number of nucleation particles improves the nucleation rate, so fine isometric crystals are mainly formed at the near surface area of coating [4].
(a) (b) Fig. 8 EDS analysis (a) grain and (b) grain boundary.
Fig. 8 shows element composition analysis of grain inside and grain boundary of cladding layer.
Through comparison, the content of Cr element at the grain boundary is higher than that of grain inside.

The powder volume contained grains with a random texture and average grain size of 50 µm.
To this end, the ratio of the number of the cells in the powder domain belonging the grains originated from the substrate to the total number of the cells in the powder domain was calculated.
Fig. 2(d) shows a decrease of FEG by the substrate grain size.
It shows that the probability of the preferred grain orientations within the AM portion of the substrate decreases by the grain size, leading to the reduction of the FEG.
CAFD results for substrates with grain sizes of (a) 50, (b) 100, and (c) 200 µm, and (d) FEG as a function of the substrate grain size.

Microstructures consisting of fine dendrites, coarse and/or equiaxial grains were also identified, as well as the presence of (α+δ) eutectoid, deformed inclusions, twinned grains and/or slip bands.
Besides, these artifacts usually possess a simple and plain typology, thus having a low museological value that allows the selection and sampling of a larger number of artifacts for study.
The impurities present in the alloy (e.g. copper sulphides) were segregated to the grain boundaries, which at present exhibit extensive intergranular corrosion outlining the grains throughout the entire cross section (Fig. 3b).
OM micrographs of ring 05/D1/IIa/M2: (a) intergranular corrosion outlining the grain boundaries (the different etching contrast between grains results from different grain orientation, a feature that is common in α-Cu grains), (BF, etched); and (b) cross section (BF, unetched).
The ring 05/D2/IIa/M4 exhibits an equiaxial microstructure with a large number of annealing twins (Fig. 6a).

The low-temperature peak may origin from the interaction of dislocation and grain boundaries.
Based on the above analysis, we conclude that the peak arise from the relaxation of grain boundaries.
The experimental results show that the damping capacity of porous Cu is higher than that of bulk Cu over the measured temperature range which imply that combining a number of macropores into a low-damping pure Cu can produce a high-damping material.
Such dislocation substructures intersecting and interacting with the grain boundaries are dragged along with the grain boundary during the viscous sliding of the boundary, so that the sliding process is limited Fig.3.
Their motion and interaction with grain boundaries will be the origin of the low-temperature peak.

Lumped capacitance model is valid when the value of the Biot number is smaller than 0,1.
A polycrystalline material contains a large number of grain boundaries, which represent a high-energy area due to inefficient packing of atoms [10].
Lower overall energy is obtained in the material if the amount of grain boundary area is reduced by grain growth.
Grain growth involves the movement of grain boundaries, permitting growth of larger grains at the expense of smaller grains.
We can conclude that the driving force for grain growth is reduction in grain boundary area.

Fatigue crack growth in polycrystalline metals is governed by a number of interacting mechanical effects at the crack tip, such as the deformation inside a plastic zone and contact between the crack faces over part of the loading cycle.
Here, we report results for two batches of AISI 316 stainless steel with different grain sizes (Fig. 2).
Effect of gauge volume and grain size.
Furthermore, a representative selection of those grains must be sampled by the diffraction technique used.
Rather, as different hkl peaks arise from different grains, a method that considers many peaks is thus increasing the total number of grains that are measured, thereby better approximating the continuum elastic behaviour.