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Laterally grown crystalline grains can be as large as 17 µm, though the grains consist of small misorientated sub-grains and some sub-grains are divided further into overlapping upper and lower sub-grains.
The grains, however, consist of many small misorientated sub-grains in mosaic form (sub-grain mosaic).
Between sub-grains, low-angle grain boundaries are formed.
At the first stage of crystallization a large number of needle-like crystallites appear from the nickel pad (Fig. 3).
The sub-grain mosaic of the large Ni-MILC grain may thus be formed.

The study examined the load response, energy absorption, and fatigue life of the A100 material in relation to the number of notches and impacts.
Further electron backscatter EBSD analysis was used in Figure 3, the grains of A100 material mainly exhibit needle like “martensite”, with a relatively disordered microstructure and uneven distribution of grain size.
Most of the grain sizes are in the range of 5 μm, there are also scattered small coherent carbides between the martensites.
Each working condition was repeated three times, and the number of impacts required for complete fracture of the test specimen was taken as its impact fatigue life.
As the impact energy increases, the number and volume of larger protruding blocks at the root of the notch also gradually increase.

Refined and uniform recrystallized grains were obtained by optimizing parameters of the high density pulses.
Microstructure of the hot rolled sheet is constituted by elongated grains along the rolling direction in the middle and small recrystallized grains near the surface.
It is obvious that the microstructure of annealed sheet is heterogeneous, with small grains near the surface and large grains in the middle.
For sample (b), a small number of dimples on the fracture surface are observed, indicating a certain ductility of the specimen.
The deformation bands are obvious within grain region in the cold rolled sheet.

This is due to the influence of niobium on the austenite grain value.
Сleavage facetes are large enough, it proves the presence of large grains in the steel.
A large number of works [1-6] devoted to the study of boron-containing steels are known.
Such elements inhibit the growth of austenite grain [1, 3, 7-9].
The martensitic transformation products inherit the dimensions of the austenite grain.

B coarsens the grain, and with the increase of the soft and ductile phase ferrite content, the strength of SA738 Gr.B steel decreased and the impact energy increased; Bi et al. [8] observed SA738 Gr after tempering at 630 ℃ by TEM The microstructure of .B steel found that a large number of carbides with various shapes were dispersed and precipitated between the lath structures, hindering the growth of grains and inhibiting the movement of dislocations.
A small number of second phase particles exceeded 300nm in size, the number slightly decreased, and distributed near the grain boundaries.
When the tempering time was 3h and 5h, as shown in Figure 2 (c) and (d), their morphological characteristics are similar to that of tempering 2h, the size of the second phase continued to increase, and a small number of smaller island-like structures appeared; at the tempering time of 8h, as shown in Figure 2 (e), the structure changed significantly, a large number of island-like structures appeared, the ferrite grain boundaries expanded and merged, and the structure was composed of large-sized polygonal ferrite and a small amount of island-like structures; When the time reaches 10 hours, as shown in Figure 2 (f), the microstructure continued to complete the transformation after 8 hours, and the size and number of island-like structures increase, to be the main phase in the microstructure.
Effect of austenite grain size on isothermal bainite transformation in low carbon microalloyed steel.
Analytical electron microscopy of grain boundaries in high-strength steels.

However, it is well known that grinding wheels consisting of abrasive grains, bonds and pores are not actually uniform continuous bodies.
Mathematical Model of Grinding Wheels Grinding wheels consist of abrasive grains, bonds and pores as shown in figure 1(a).
Figure 2 shows the relationship between the static stiffness k and the grain size # for vitrified and resin bonds.
The relationship between grain size # and static stiffness k of each bond can be shown as inverse proportion, and static stiffness of bond k depends on grain size #.
It may be depending on the decreases the number of bonds, that is, the number of spring elements.

Each measurement involved more than 200 grains.
The average grain sizes of Al-0.3Fe and Al-0.7Fe alloys are 86 and 71 µm respectively.
For the rolled rods (Fig. 3(b, d)), a number of low and medium angle boundaries with deformed grains were present.
The deformed structure was well organized and a number of subgrains were formed with neatly arranged boundaries between 1 and 15°.
Humphreys, Review-Grain and subgrain characterisation by electron backscatter diffraction.

The grain size was only 2.8μm.
When the sintering temperatures were increased from 1000℃ to 1300℃, a clear tendency of grain growth was found.
The grains in TNO ceramics coarsened from 0.2μm to 2.8μm when the sintering temperatures were increased from 1000℃ to 1200℃.
The above results indicated that a fully dense TNO ceramic with a fine grain size was obtained in this study.
Acknowlegement The authors thank the Prosperity Dielectric Co. and the National Science Council for their support of this project under contract number NSC 100-2622-E-150-018-CC3.

The number of hillocks observed on the surface in 500 nm2 area is 60±10.
The hillock formation efficiency calculated by dividing number of observed hillocks by number of incident ions is almost 5%.
The grain height also decreases to 4.5 nm due to shape change.
The as-deposited film does not show nanocrystalline grains.
These hillocks are visualized as nanosized grains in AFM 2D images.

With the increasing of weight percentage of Al, the number and size of arborescent crystals increased obviously, as well as the microhardness, the maximum was 957.9Hv, 1.3-1.5 times of the layers with below 6%wt Al.
With the increasing of Al content, the number and size of arborescent crystal increased obviously.
Grain abrasion and chamfered plough friction were caused on the layers with 6% and 8% Al.
Their friction ring surfaces are micro-cutted by deciduous Ti3Al ceramic grain and distribute mass abrasive dusts and deeper chamfered plough ditch.
With the increasing of weight percentage of Al, the number and size of arborescent crystals increase obviously.