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Experiment results show that adding rare earth element to the welding rod coating could make the grains fine, increase the content of acicular ferrite and improve the hardness and abrasion resistances of weld metal.
Adding rare earth element to steel has the effects of making the grains fine, refining grain boundary and improving the hardness and abrasion resistances of weld metal.
Table 1 Welding Parameters Welding Current [I/A] Welding Voltage [U/V] Interpass Temperature [t/°C] Drying temperature [t/°C] Drying Time [h] Depositing Number Welding Bead [mm] 160 30 100±10 380 2 3 Layers 70 Hardness, organization experiment and conditions Hardness was measured by Rockwell Hardness Tester (HR-150A).
The reason is that the REE which transition to the weld line easily gathered to the grain boundary, it hindered the growth of crystal particle; in addition, tiny high melting point of rare earth oxide inclusions could become the non-spontaneous nucleation particle of acicular ferrite, thereby increased the percentage of acicular ferrite in weld line [3].
Two main reasons as followed: ①Er and Ce can form solid solution in the matrix, the biggish atomic radius of Er and Ce will cause intense lattice distortion of matrix, play a role in solution strengthening. ②Compounds formed by the rare earth elements could refine the organization of alloy, also play a role in fine-grain strengthening [4].

Results and discussion The distribution of grain size in 0.08C16Cr11Ni3Мo steel samples obeys a bimodal distribution with peaks at 10-25 and 140-150 µm with the grain body containing a large number of dispersed 1-2 µm carbides arranged in chains visible as dark stripes.
Uniaxial deformation of the irradiated 0.08C16Cr11Ni3Мo steel both at room temperature and at T = 350 °C resulted in a significant decrease of the average grain size and an increase in the number of small intra- and intergranular carbides.
The highlighted fragment is magnified to ×1230 The grain size in 0.12C18Cr10NiТi samples after creep tests at 450 °C is 15–25 µm (Fig. 4b) with very small number of extra-large grains.
Large numbers of inter- and intragranular carbides were observed with sizes of 2–3 µm and ~1 µm respectively.
Very small carbides forming chains were observed in the grain bodies, while the grain boundaries remained relatively clear.

The size of the crystal grains ranged from 10 nm-50 nm.
All Ni-alumina grains are looks regular an fine, The average diameter of those grains probably were about 3 nm, the nickel is evenly distributed on the outer surface of the alumina.
Therefore, as long as know the variables f, d, ε′, ε″, μ′, μ″ in the equation, the power reflection coefficient can be obtained : R=20 lg G (5) where ca = interface adhesion; d = friction angle at interface; and k1 = shear stiffness number.
Conclusions A ceramic-based composite with Ni deposited on Al2O3 grain was fabricated in a controllable way.
The microscopic examination indicates that metallic Ni is uniformly deposited on the grains, and its grain size is about 20 nm.

The even numbers of summation of indices, h+k+l, of the peaks indicates the crystallographic symmetry of the BCC structure due to the extinction rule.
This is because higher temperatures and slower cooling rates allows more time for crystal grain growth of fewer nuclei, resulting in coarser grain structures.
Smaller grains lead to a higher volume fraction of the grain boundaries.
Higher laser power resulted in larger grain sizes, while smaller grains seemed to improve the strength of the L-DEDed samples.
Acknowledgements This work was supported by JSPS KAKENHI Grant Number JP22H05280.

The light points in the figures are the crystal grains.
Conversely, the final finishing surfaces lapped with SiO2 polishing slurry were processed to a smooth surface, on the surface polished with SiO2, most crystal grains turn to light, which indicate that the workmaterial removal is initiated in the grain, with little breakdown of the grain boundary observed, i.e. a part of the grain is removed instead of the spalling of the whole one.
The reason may be the decreasing load and the increasing abrasive grits numbers between the pad and workpiece.
On the surface lapped with the #2000 and #3000, a number of areas were confirmed where the material was removed by means other than the breakdown of the grain boundary.
These pits are considered as the gaps between the grains.

It is known that nanocrystalline materials possess ultrafine grains with a large number of grain boundaries that may act as fast atomic diffusion channels [3].
This may be attributed to the heterogeneous nature of the plastic deformation both within and between grains [6].
From the dark image, one can see nanocrystallize grains of which the shape is roughly equiaxed.
The average grain size in the top surface layer is approximately 10 nm.
In conventional nitriding of coarse-grained sample, nitrogen diffusion in the austenite lattice dominates.

Microstructural analysis revealed that miniaturized specimens contained 1–2 large grains, whereas large specimens exhibited 5–7 smaller grains in the cross-section, respectively.
In contrast to the eutectic colonies of lamellar Sn and Pb found in Sn-Pb alloy, SAC solder joints typically consist of only a small number of grains, with more than 90 % of the solder having a β-Sn anisotropic Body Centered Tetragonal (BCT) lattice structure, resulting in high anisotropy in each SAC grain.
The miniaturized specimens contained only 1-2 grains within its cross section, while the large specimens contained more, namely 5-7 grains.
It can be seen also, that the large specimen’s grain structure is a typical casted structure, which means the grains grew from the sides to the inside of the original bar.
The smaller yield strength can be caused by the fact that large grains with less constrains deform easier compared to a bulk material where the grains constrained more by the neighboring grains.

The creep mechanism of the composite is dislocation and grain boundary sliding control.
The current study results of magnesium alloy creep show that their creep deformation mechanism is dislocation slip mode and grain boundary sliding mode[9].
At a high temperature, plastic deformation of the matrix should be evident, that is, there exist a large number of dimples; and the fracture surface should have clear micro-cracks.
As the temperature rises, β-Mg17Al12 phase decreases in the number; the weaker it is in impeding dislocation, the more easily sliding movement of grain boundary can be carried out.
The creep mechanism of the composite is the same as the one of the matrix, and it is the mechanism of dislocation slip and grain boundary sliding.

The surface roughness and average surface grain size obtained by AFM is 2.39 nm and 60 nm for the crystallized film, respectively.
From the relatively steeper profile of TO mode in the side of higher wave number for the sample S-500 and S-650, we can conclude the existing of bits of nano-Si in the films.
It can be seen from the Raman spectrum of S-800 that the shape of TO mode in the side of lower wave number is more flat than that in the side of higher wave number.
The poly-Si grains of about 60 nm are detected in the surface, and the roughness is about 2.39 nm.
The surface roughness and average surface grain size obtained by AFM is 2.39 nm and 60 nm for the crystallized film.

Three representatives of one-carbide hard alloys (WC 94% Co 6% (fine grain); WC 92%, Co 8%; and WC 85%, Co 15% alloys) were chosen to determine the temperature influence on the stress intensity factor.
The number of WC grains destroyed by the crack and the number of grains bypassed by the crack along the grain boundary were registered.
Experimental results show that removal of thermal stresses by heating increases WC grain strength, but decreases the relative strength of interphase boundary.
The correlation existing between KIC and W is provided by Formula 3: KIC=β×(HV×W)1/2, (3) where, β is the dimensionless factor, equal to 8.89x10-2; HV is Vickers hardness number HV, МРа.
Upon the completion of the required number of measurements, the device is switched off.