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The bond tensile strength were obtained by subjecting three numbers of friction stir cladded copper stainless steel joints to ram tensile test for each overlap conditions.
For the samples cladded at 50 % shoulder overlap the much wider zone of DRX austenitic grains around the heavy deformed copper grains.
Moreover, an intercalated pattern of copper grains and austenite grains are observed in the copper deformed zone at the top.
This is mainly due to proper mixing of copper grains with recrystallized austenitic grain and stronger bonding interface.
The extent to which the austenitic grain mixed with copper grains, volume of austenite grains recrystallized around the deformed copper grains, fragmentation of austentic stainless steel particles, micro level defect formation were influenced by the shoulder overlap ratio.

In Figure 2a, when the time interval is 0 s, the microstructure of the test piece had been subjected to the compression deformation of 0.35 by accumulation, so long ribbon structure of crystal grain could be seen obviously along the deformation direction, and small "string-shape" dynamic recrystallization crystal grains were distributed unevenly in the crystal boundary simultaneously.
Elements C Cr Ni N Si Mn S P 304 stainless steel 0.035 18.0 8.1 0.05 0.43 0.95 0.012 0.028 For the dual-interval time interval of 0-5s, tiny crystal grain appeared at grain boundary and interior of the grain due to protruding nucleation, indicating the occurrence of static recrystallization.
It can be seen that the number of the tiny and even crystal grain from the static recrystallization increased obviously in the crystal boundary (Figure 2b).
When the time interval was 10s, the crystal grain of the static recrystallization increased rapidly, producing continue refinement of the crystal grain (Figure 2c).
After the complete static recrystallization, the grain size tended to be stable (Figure 2d).

In that case β modification arises, when we assume the grain shape but it is destructed.
Whereas laboratory prepared samples are characterized in massive prismatic grains, the reference gypsum is very fine-grained because according to all morphology feature it was put to sort by grinding.
Mentioned observing comes to the conclusion that used laboratory vibratory mill is not fundamentally suitable for separation of relatively soft gypsum grains because instead progressive shortening of long prismatic grains, since it resulted in share increasing of submicroscopic particles arising by microscopy grains abrasion of macroscopic grains
That is why for the next works it is suggested to use other type of laboratory mill with different principle of separating which would break prismatic grains than to spread by pressure.
Registration number CZ.1.07/2.3.00/20.0111. and FR-TI2/653 „Komplexní stavební program na bázi vysokohodnotného sádrového pojiva z druhotných surovin“ References [1] FRIDRICHOVÁ, M., KULÍSEK, K., ZELENKOVÁ, R.

Submicrocrystalline Cu obtained by HPT was studied in a number of publications including [24].
These disks were deformed in anvils under a load of 4 GPa at a rate of 0.3 rev/min, the number of revolutions being 1, 3, 5 and 10, at room temperature and in liquid nitrogen (the temperature of samples being 80K).
In some grains, one can see an intricate diffraction contrast indicating the presence of high internal stresses characteristic of structures obtained by HPT, but the amount of such grains is not so big, the dislocation density in many grains being quite low.
Grain boundaries are mainly thin and straight, and dislocation density in grains is low.
Grain sizes do not increase, grain boundaries are mainly thin but curved, and moiré pattern is observed in some areas (Fig. 5).

continuous grain boundary, different particle size varies.
The heating temperature on influence of austenitic grain The heating temperature and holding time on influence of austenitic grain see in figure2.
Fig.2 The heating temperature and holding time on influence of austenitic grain Fig.3 The deformation temperature and deformation extent on influence of austenitic grain The deformation temperature and deformation extent on influence of austenitic grain The deformation temperature and deformation extent on influence of austenitic grain see in figure3.
But as deformation extents continue improved, the austenitic grain hasn’t changed much; when deformation temperature was 1020˚C, as the deformation extent increased, the austenitic grain grew up.
But as deformation extents continue improved, the austenitic grain hasn’t changed much; when deformation temperature are ≤980˚C, deformation extent below 50%, the austenitic grain hasn’t changed much.

The pore numbers in the foamed geopolymer were greatly increased by releasing the hydrogen gas, which was produced from the chemical reaction of zinc and aluminum powders in a base solution.
Increasing the number of pores in a geopolymer can lighten the main body of a structure, and enhance thermal insulation [2], and afford fire protection.
The morphology contains three different structures: fine-grained, plate structure, and white precipitate.
According to one reference [6], plate precipitate is caused by incompletely reacted geopolymer, and the fine-grained structure is attributed to the completely reacted geopolymer.
Fig.4 Microstructure of a geopolymer with plate and white precipitate, fine-grained structure Fig.5 SEM/EDS of (a) geopolymer and (b) the white precipitate Fig.6 shows the microstructure analysis of the foamed geopolymer.

The large number of technological parameters involved complicate the selection of an SLM mode for obtaining a product with the required structure.
Analysis of the cross sections shows that the material has 2 types of grains (Fig.4).
The first type of grains is inside the field corresponding to the trajectory of the laser.The orientation of these fields causes the anisotropy of the mechanical properties of the material.
There are larger grains at the intersection melt pools of neighboring tracks.
One would assume that the structure of these specimens would be characterized by a large number of pores.

The film annealed at 850°C possesses a smooth surface, but an important number of small holes between grains and bigger boundaries may be observed regularly on its surface, inducing here that its density is lower when compared to the other films.
That confirms the link with the grain size as we had the same grain size with the (80/20) and (90/10) compositions [6].
These three films exhibit grains with an average size of about 110 nm, so the annealing time has no effect on the grain size in case of one hour maximum time.
These results highlight that the tunability is a function of the grain size, and here, SEM pictures have shown a 110 nm average grain size for all films annealed at 950°C.
Moreover, it cannot be linked to the grain size as it remains constant here.

The microstructure of the casting alloy consists of α-Mg phase matrix with a primary β phase (Mg17Al12) at grain boundaries.
Precipitated β phases of the magnesium alloy increased with aging time gain and the grains were refined.
A large amount of β phases and smaller grains brought on corrosion resistance improvement.
Conclusions 1.The microstructure of Mg-7.3 Al alloy consists of α-Mg phase matrix with a primary β phase Mg17Al12 at grain boundaries.
A large amount of β phases and smaller grains in the alloy brought on corrosion resistance improvement.

The result shows a higher UTS in water-cooled system because the microstructure of specimens comprised a finer grain size of Ag3Sn and (Cu,Ni)6Sn5 IMCs in β-Sn matrix (Fig.4) [7,8].
The finer grain sizes provide a lot of grain boundary, resulting in an inhibition of a movement of dislocation.
The water-cooled systems (a faster cooling rate) produced a finer grain size of Ag3Sn and (Cu,Ni)6Sn5 IMCs compared with the mold-cooled systems.
Acknowledgements This work has been supported by Prince of Songkla University Research Fund (Fiscal Year 2016) under the contract number SCl590647.
Zong, Effect of grain size, texture and density of precipitates on the hardness and tensile yield stress of Mg-14Gd-0.5Zr alloys, Mater.