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BT crystal is a typical lead-free ferroelectric and there have been a number of reports on its domain engineering [13-16].
The grain size was measured using a scanning electron microscopy (SEM).
F110 dependence on piezoelectric properties for [110] grain-oriented BT ceramics. of the grains normal to surface, which revealed that there was no anisotropic microstructure in the ceramics.
Therefore, grain-oriented BT ceramics with smaller grain sizes below 1 µm should be prepared in the future.
In the future, the grain size should be below 1 µm for grain-oriented BT ceramics.

Ultrafinegrained (UFG) materials typically exhibit average grain sizes in the range of 100 nm to 1 µm.
Only a rather small number of investigations were focused on large-scale ECAP [5-8].
The annealed material exhibits a grain size in the range of 200 to 500 μm.
We note that Xu et al. [11] reported similar observations; they documented a somewhat higher area fraction of equiaxed grains in regions of higher hardness, and more elongated grains in low-hardness regions.
They [11] argue that the grain shape tends to become more equiaxed when the imposed strain is sufficiently large.

The number of distinct phases within the material microstructure is highly variable, e.g.
An ensemble is a set of a large number of media that are identical in terms of the macroscopic scale but differ in their microscopic details.
The total number of paths is equal to W*H + (W-1)*H
The paths from the matrix of repetitions are used for the record of the number of occurrences in the selected phase.
In Algorithm 1 and 2, the matrix of absolute occurrences is simply divided by the number of pixels in the image, i.e. by W*H.

Charges gathered at grain boundaries resulting in space charge polarization at grain boundaries.
As number of charges at grain boundaries decreases polarization also decreases.
At Lower frequencies resistive grain-grain interface or boundaries restrict the motion of charge carriers among Fe2+/Fe3+ at octahedral B site.
First layer made up of conducting grain while second layer made up of resistive grain boundaries.
Resistive grain boundaries are significant at low frequency region.

In addition, it is seen that there are a number of primary phases with globular- or particle-like in the microstructure.
There is the obvious supercooling held at 605 and 600˚C for the melt, in which a number of nuclei are formed and the roots of the primary dendrite are fused to form “grains multiplication”.
The grains with suitable crystal orientation will fuse together to form the coarser grain.
It is point of view from energy that the system is kept the substable state because of the bigger surface energy after a great number of fine nuclei formed in the melt, and that the combination and growth of grain are favourable to the reduction of the system energy.
a() b() Fig. 3 Effect of holding time on size (a) and shape factor (b) of primary phase in the alloy held at 600˚C Conclutions When isothermal holding at 615-595˚C, the evolution charecteristics of primary phase in A356 alloy with the decrease of holding temperature is: dendrite grain→rosette grain→closing to globular grain→globular grain with the better roundness→coarser grain with particle-like.

However, in that model that the MMR is inversely proportional to the number of active abrasive particles, which is a paradox according to the well-accepted models.
Assuming that the grains are identical spheres of diameter dg, MMR was expressed as ( )3/ 2 ' w g Z knf d δ= (1) where δ is the depth of indentation; n is the number of impacting particles per cycle, f is the frequency of vibration; k is coefficient.
On the basis of this model, the researchers studied the relationship between the MMR and the controllable process parameters (static force, ultrasonic vibration amplitude, rotation speed, abrasive grain size and abrasive grain number).
MMR Model in TUSG Complex Ceramics in Ductile Regime In order to establish the MMR model in TUSG complex ceramics in ductile regime, the assumptions for the model development are as follows: 1) Diamond grains are rigid spheres with the same diameter; 2) Complex ceramics is rigid-plastic; 3) The volume removed by one grain per TUSG cycle is equal to the intersection volume of the grain swept envelope and the workpiece; 4) The shape of the ground grooves is approximate to a part of inner cylinder.
According to the geometric relationship between grains and grinding parameters, a model of material volume removed by a single grain with ultrasonic assistance is simplified to 2 2 2 g g gmax g g g g gmax gmax g g 2 arccos 2 2 2 2 d d a d d d V a a l d   −           = − − − − ⋅                       (13) Therefore, MMR model is given by the product of the volume of material removed by one abrasive within one vibration cycle, Vg, the frequency of vibration, f, and the number of active diamond abrasives, Nd, that is ' w d gZ N fV= (14) Eq.14 shows that the relationship between MMR and material properties of complex ceramics, machining mode, features of grinding wheel and parameters of acoustic system.

Parasiz investigated the effect of grain size and specimen size on the deformation distribution through the sheet thickness in microbending of CuZn30, and indicated that the plastic deformation will penetrate to the inner regions of the sheet for coarse grained structures when the specimen size is miniaturized [4].
These experiments show that obvious size effects are exist and being related to the mean grain size, but quantitative relations between them are not established.
So, in this paper, the following equation is used to calculate the material intrinsic length: (10) where, is the number of grain lays across the foil thickness.
That is to say, when the foil thickness is decreasing, the grain numbers across foil thickness decreasing, the effects of plastic strain gradient will be stronger than thicker foils, in which more grains are along the thickness.
In addition, the authors argue that the average grain numbers across the foil thickness are taken into the modified material intrinsic length account.

As a result, the weight change increased with time, with fine grain HT1000 sample recorded lower weight gain compared to coarse grain HT1100 sample.
The average grain size of HT1000 and HT1100 are 56.72 μm and 64.77 μm which are considered as fine grain and coarse grain size, respectively.
The fine grain size of HT1000 sample exhibited little weight gain compared to coarse grain size sample of HT1100.
The fine grain HT1000 sample demonstrate a lower weight change compared to the coarse grain HT1100 sample.
Acknowledgement The authors would like to acknowledge the support from the Fundamental Research Grant Scheme (FRGS) under a grant number of FRGS/1/2020/TK0/UNIMAP/02/43 from the Ministry of Higher Education Malaysia.

Low atomic number of this element makes it difficult through Electron Probe Micro Analyzer.
During solution annealing treatment, it is expected that boron should precipitate at the grain boundaries.
Boron autoradiography (Fig.2b) shows the boron precipitation around the grain areas, only difference being of the smaller grain size.
It was not decorated around the grain boundaries, as it has been observed in the steel with higher boron.
In steels with higher boron content and additionally alloyed with copper, the borides seems to evenly precipitated within grains and in grain boundaries as small inclusions.

The ECAP processing was performed using special die with an angle of channels intersection Φ = 90°, the number of ECAP passes was 2 and 4.
The average grain size of ferrite is 10.6 microns, the average grain size of pearlite is about 6.7 microns.
The increase in the number of ECAP cycles to 4 has led to a significant reduction in the size of the structural components.
Enhance the number of ECAP passes to 4 led to increased yield strength to 1140 MPa, which is equal to the increase of 250%.
The drop in impact strength after 2 ECAP passes was 2.5 times at the room temperature, enhance the number of ECAP passes to 4 led to decrease of impact strength in 10 times.