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Moreover, the average size of austenite grain may be increased at high quenching temperature.
A large number of ferrite and residual carbides were distributed in the sample, as illustrated in Fig. 4(a).
On the other hand, the growth and coarsening of grain was inhibited by the fine carbides, especially on grain boundary, which resulting in fine-grain strengthening [10].
Consequently, the hardness was improved by the large number of fine carbides in the sample.
Formation of Ultra-Fine Grain Structure of Plan Low Carbon Steel.

With this assumption, the flow process is grain boundary sliding accommodated by diffusional processes.
This stress can be estimated from the equation: (9) where is the shear stress acting on the pile-up plane, L is the pile-up length, G the shear modulus and N is the number of pile-up dislocations.
It is now accepted that yttrium segregates at grain boundaries or at the dislocation cores in Y-TZP.
The agreement is excellent for all the different grain sizes considered in reference [12].
Retamal, Grain dynamics and plastic properties of highly refined materials ,Phys.

BSE images generate a contrast between phases of different atomic numbers indicating the light (gray) and dark (black) colors as W- and La2O3-rich regions, respectively.
As seen Fig. 4a and 4b, micron- and submicron La2O3 particles have a homogenous distribution throughout the microstructure that are located both at grain boundaries and at grain interiors.
Increase in La2O3 amounts provides a significant decrease in the grain size of W1Ni matrix alloy.
Acknowledgement The authors would like to express their appreciations to the Scientific and Technological Research Council of Turkey (TUBITAK) for funding the project with the number of 110M130.
Yoon, Segregation-induced grain boundary premelting in nickel-doped tungsten, Appl.

On the contrary, under severe wear conditions, the specimens with elongated �-Si3N4 grains exhibited high wear resistance due to prevention of the propagation of microcracking by these grains.
Therefore, a considerable number of studies have been made on the tribological behavior of these materials[1-6].
A diversity of microstructure in Si-based nitrogen ceramics Crystalline phase Amount of grain boundary glassy phase � only �/� composite � only Large �-Si3N4 (isotropic grain) �/� composite Si3N4 (isotropic + elongated grain) �-Si3N4 (elongated grain) Quite small �-sialon (isotropic grain or elongated grain) �/� composite sialon (isotropic � grain + elongated � grain) �-sialon (elongated or isotropic grain) The amount of residual glassy phase can be drastically reduced in these sialon ceramics relative to silicon nitride because their densification is achieved with the aid of a transient liquid.
The nominal composition in the Y-�-sialon plane can be expressed simply by Y(m,n), where m and n are numbers in the chemical formula of Ym/3 Si12-(m+n) Alm+n On N16-n.
The composite sialons exhibited a bimodal microstructure where elongated �-Si3N4 grains of a few microns in length and submicron diameters are dispersed in fine �-sialon matrix grains (Figs. 2-a,b).

Cryogenic treatment can inhibit the dynamic recovery in the rolling process and thus refine the grains.
Therefore, cryogenic asymmetric rolling energy is an effective method to improve the degree of grain refinement, as well as the strength and elongation.
Magalhães et al. [17] found that cryogenic asymmetric rolling could refine the grains of AA6061 and improve the strength.
Acknowledgements The authors thank for the financial support by National Natural Science Foundation of China (Grant number: 51674303), National Youth Thousand Plan Program of China, Huxiang High-Level Talent Gathering Project of HUNAN Province (Grant number: 2018RS3015), Innovation Driven Program of Central South University (Grant number: 2019CX006), and the Research Fund of the Key Laboratory of High Performance Complex Manufacturing at Central South University.
Kestens, Grain and texture evolution in nano/ultrafine-grained bimetallic Al/Ni composite during accumulative roll bonding, Metals 53(2018) 12553-12569

SPM images show that ultrathin Al films consist of equiaxial in-plane grains.
From fig. 1, all samples have equiaxial in-plane grains.
The in-plane grain size tends to be larger when the thickness of Al films increased.
At lower substrate temperature, the grains are smaller and more uniformly distributed.
Volume 44 (1980) number 24

In spite of any of these requirements alone can be satisfied in a broad range of materials, whereas their combination severely limits the number of available options [1, 2].
Similar abnormal grain growth was also observed in A4Nb2O9 (A=Mg, Ni) by RS process [17].
The entrapped pores in grain were attributed to the evaporation of Li at elevated temperature [9, 12, 18].
Therefore, the improvements in εr and Qxf values can be attributed to the increase in the density as well as grain growth, whereas the deterioration might be caused by the abnormal grain growth coupled with a decrease in density [23, 24].
The density and grain size play a significant role to control εr and Qxf in Li2ZnTi3O8 ceramics system.

The formation of wdmanstatten structure was concerned to the composition of steel, austenitic grain size and cooling speed after rolling.
There were bainite and westergren existed at the edge of 9#, both the two structures distributed unevenly with coarse grains.
In this paper, the influence of different cooling rate to grain size were determined, the results were shown in Fig.4.
Fig. 4 The relationship between grain size of HRE400 and cooling rate As the Fig.5 shown, with the increasing of cooling rate, the grain size became smaller, while became bigger when the cooling rate is greater than a certain critical value.
At the same time, the overquick cooling rate could relate to the precipitation of ferritic in the supercooled austenite grain boundary firstly, and the ferritic would grow in a certain direction to the austenite grain boundary, then the westergren structure formed in the shape of acicular or plume.

Within a grain Kikuchi patterns are identical, but they change when a grain boundary is found.
However, the number of measured orientations must be enough to be compared to results by X-ray or neutron diffraction; 500 to 1000 grain orientations are sufficient [8].
Recrystallization mechanism: cube sub-grain growth by bulging of a prior grain boundary.
Cube grain growth kinetics.
From the individual orientation measurements, the ODF and MODF can be calculated if the number of grain orientations is sufficient and the area studied is representative of the whole sample.

The results show that there are 26 species in the SSBs, with species density 6809~30644 grains/m2 and ecological dominance at 0.51~0.81.
The number of halophytes is 8 (30.8% of the total number of species).
Species number of SSB Sampling plot sampling layers total 0~5cm 5~10cm 10~15cm Mean S.D Sum (grain/m2) Mean S.D.
As for Jiyunhe wetland, S. glauca, S. viridis and S. glauca are the dominant species (Table. 2), according to the number range of wetlands’ SSB (103~106 grain /m2) [16].
Numbers of seeds in all plots reduce significantly when the depth increases.