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When the carbon content is the same, the higher chrome content, the greater the number of carbide eutectic, the higher hardness of high chromium cast-iron of grinding ball.
It can improve cast structure of high chromium cast-iron, refine grains and increase the toughness of the material.
Rare earth ferrosilicon can also refine primary austenitic grain and carbide.
Meanwhile a small amount of molybdenum can refine grains and improve micro-hardness of carbide.
Meanwhile copper can also refine grains, strengthen matrix organization.

Because the heating is highly concentrated, fast cooling rates ensue which may lead to the formation of very fine grains near the welding interface [7].
The temperature was selected in order to minimize microstructure modifications (e. g. grain growth, phase transformations) of both materials.
The microstructure of the ZERON 100 base material consists of alternating layers of elongated ferrite and austenite grains.
Under the same magnification which was used for Fig. 2, no significant changes in grain morphology can be visualized after the proposed heat treatment.
Tu, Finite element analysis of the effect of welding heat input and layer number on residual stress in repair welds for stainless steel clad plate, Mater.

The test piece had the microstructure composed of fine ferrite grains and pearlite colonies.
(3) where fn is a volume fraction of the n-th grain and E is the Young’s modulus.
Therefore, the stress conditions to minimize the work w at a certain fixed total volume fraction v can be found by solving the simultaneous equations as follows for all the grains involved
　　 (4) To simplify the situation by assuming that the test piece was composed of one grain and making x’= x, y’= y and z’= z, and to solve the equations, the following solution can be obtained
Acknowledgement This work was supported by JSPS KAKENHI Grant Number 21560120 and the authors would like to thank Sumitomo Metal Industries, Ltd. for its donation of experimental materials.

According to this rule, the cooling curve is divided into a number of small time steps, and the amount of transformation at each time step is calculated using the JMAK equation.
Additionally, αi denotes the thermal expansion coefficient, np is the total number of the involved phases, T and T0 designate the current and initial temperature, and I is the identity tensor.
At low temperatures, the grain boundaries prevent the dislocations of the grains, and thereby they provide a high strength.
However, the grain boundaries become weaker at high temperatures.
This is due to the fact that the recovery and the recrystallization of the grains reduce the dislocation density, which has a direct effect on the transformation.

Muta et al. [20] investigated the structural and thermoelectric properties of rare earth (Y, La, Sm, Gd, and Dy) modified SrTiO3 and he examined the influence of the doping and the rising of the temperature on decreasing the thermal conductivity, Indeed, the number of merits is enhanced by the difference in the thermal conductivity.
The linear intercept method was used to calculated the average grain sizes of all compositions and were found to be in the range of 8.22 to 12.5 µm, indeed the largest value is associated with Sr0.96Y0.04TiO3 compound.
The prepared ceramics are relatively dense, consisting of irregularly oriented grains in the form of flat blocks with the existence of pores in the samples.
SEM analysis revealed that the presented ceramic samples are relatively dense, containing of irregularly oriented grains in the form of flat blocks.
Morse, Engineering grain size and electrical properties of donor-doped barium titanate ceramics, Ceram.

Fe-Cr-Si-B alloy powder with grain size of 50~70μm is preseted on the sample surface.
The interface is white and light because of solid solution of a large number of Cr in the low carbon steel substrate and highly corrosion resistant.
Fig. 2 SEM morphology and EDS analysis of cladding layer surface It can be seen from the SEM photos of cladding layer surface in figure. 2 that the hypereutectic area of cladding layer surface is composed of dense radial matrix structure and a large number of strip-bulk precipitation.
Conclusions Alloy coating by argon arc cladding is mainly a large number of block and strip eutectic distributing in the radial organization which is a mixed organization of martensite and γ-(Fe-Cr-Ni-C) alloy solid solution.
As a result of a large number of compounds precipitated in the cladding layer, supersaturated solid solution strengthening caused by Cr, Si dissolving into solid solution，and fine grain strengthening caused by rapid heating and rapid solidifying the coating，the highest hardness of the surface can reach 600HV.

The relationship diagram obtained by a large number of quenching experiments is composed of five zones, which reveal the forming process of TiC particles in a FeTi-C melt.
Due to rapid solidification, the size, shape and number of TiC particles synthesized in the melt were retained in the quenched samples.
But, if above reaction is uncompleted, unreacted C will precipitate at austenite grain boundaries in the shape of fine graphite.
Results and Discussion Fig.1 shows the processing parametersmicrostructures diagram obtained by a great number of quenching experimental data.
At point 1 in zone A, the solidified microstructure of the melt contained a lot of graphite aggregated at grain boundaries except for TiC particles, as shown in Fig.2(a).

A number of methods have been proposed for cooling [3-10].
In the experimental tests, the relationship between the number of nozzle nnzl and surface roughness was studied.
This shows that the grain cutting ability was increased.
Table 5 and Fig. 4 show that the loading current would increase when the number of nozzle nnzl was increased.
This shows the grain cutting ability was increased due to the increase in coolant flow.

The structure of the sprayed layer has extremely weak TiNiHf etchability with conventional reagents, largely because of strong grain refinement as a result of high-speed heating, rapid cooling, and significant deformation (Fig. 4), which provides special structural effects.
In subsequent contact with operating body more nano-grains are formed.
The resulting TiNiHf coating has a nanoscale structure with grain size of 80 - 120 nm (Fig. 4).
Crystallization in high-speed gas-flame spraying is accompanied by the formation of nuclei in long-range fluctuations, whose number and size are determined by degree of supercooling.
Acknowledgements This work was performed as part of State Task № 9.555.2014/K, with the financial support of the Ministry of Education and Science of the Russian Federation and President Grant number МК-5445.2016.8.

The microstructure of the 1060 aluminum wire is mainly composed of uniform fine equiaxed grains and larger columnar equiaxed grains.
Fig. 6a shows that there are fewer fine equiaxed grains in the middle region after printing.
This phenomenon may have resulted from the extrusion of the molten aluminum by the printer nozzle causing the equiaxed grains inside the stacked layers to become finer.
In contrast, Fig. 6b shows that the number of fine equiaxed grains in the flank region are remarkably increased; the number of black graphite particles are increased as well.