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The grain size of ferrite in center of the rebar was estimated using a line-intercept method.
The closer to the surface, the cooling speed was faster, which was beneficial to form smaller grains.
Therefore, ferrite grain size in interlayer was smaller than that in center.
Relative content of different microstructure in center and size of ferrite grains have been measured.
The results indicated that there were 59.3% ferrite, 32.1% pearlite and 6.6% bainite, the average grain size of central ferrite was 7.1μm, and the grain size number, grade 11.

The presence of alloying elements such as Ni, Sn, Mn and Pb makes the Cu-Ni alloys highly suitable for a number of applications in the petroleum, aerospace and military industries.
The microstructures of this Cu-Ni alloy are characterized in terms of grain size and primary and secondary dendrite arm space, and element segregation.
It shows that the grain average size, the PDAS and the SDAS decreased in sand mold, graphite mold and steel mold, respectively.
It is found that the grain average size, the PDAS and the SDAS reduce obviously with the increase of cooling rate and decrease of solidification time.
Experimental results show that the grain average size, the primary and secondary arm spacing were refined obviously with the increase of the cooling rate. 3.

Conduction due to the electrolyte–electrode interfacial effect contributes at very low frequencies (~ kHz), while the contribution due to the grain boundaries generally remains up to kHz or MHz [7, 8].
Subscripts, ‘interface’, ‘g.b.’ indicate the lossy polarization between electrolyte-electrode interface, the grain boundary conduction.
This depression is interpreted as the effects of the extrinsic polarizations; the lossy interfacial polarization between electrolyte-electrode and the polarization at grain boundaries.
Extrinsic polarizations derived from the interface and the grain boundary completely relaxed and their contribution disappeared near 1 MHz.
The conductivity spectroscopy technique enabled the simultaneous quantifications of the conduction contributions, namely electrolyte–electrode interface, grain boundaries, UDR, and optical phonons, to the total conductivity.

The grain size of the sample was measured using intercept method.
From Fig. 1 it is observed that the grains of the SCT sample are smaller than the untreated sample such refinement of grains in non-ferrous alloy (Al alloy) was also reported by Wang et al., [12].
The ASTM Grain size number for untreated sample is 9.59 whereas, for treated sample it is 10.75.
Due to the grain refinement, the hardness of the SCT sample was enhanced compared with untreated sample.
· Grains of shallow cryogenic treated sample are finer than untreated sample

There are a number of superplastic forming techniques have been developed and applied to superplastic alloys [5-6].
The aim of present work is to study the superplastic forming behaviour of fine-grained CuZnAlZr shape memory alloys sheet.
The purpose of addition of zirconium in CuZnAl alloy is to refine the grain of the alloy.
The average grain size and a/b phase ratio were determined from these micrographs and are listed in Table 1.
Table 1 Average grain size and a to b ratio Treatment Conditions Average Grain Size (μm) a to b Ratio As rolled 16.85 0.31 Treatment at 550oC 17.32 0.34 Treatment at 600oC 20.34 0.29 Treatment at 700oC 51.04 0.03 Dome height and dh/dt.

The S-N curves use the applied stress amplitude versus number of cycles.
The local strain of each individual grain could be mapped through the image analysis of all the grains [9].
Grain structure, black lines are grain boundary, red lines are twin boundary, and white points are the misorietations with angles less than 10°, (b).
Grain A has an [011] orientation and has higher amount of LAGB.
They got impinged with the grain boundaries.

The results showed that GZO thin films with high quality could be fabricated under the high pressure of argon.When substrate temperature is 250℃ or below, surface morphology of thin films can be significantly improved.With the increase of substrate temperature, the crystal grain become larger, the crystal boundaries narrow and become clear, and reach a best case at 250℃.
The atomic numbers of the Ga and Zn differ only by one.
But when the temperature rised to 300℃, the growth of the grain inevitably brought the surface roughness.
The influence that temperature acted on resistivity mainly lied in the effect that temperature acted on its grain shape, size and grain boundaries size.With the temperature increrasing, grain became larger and combine closely, grain boundaries became clear, thus the distribution of crystal became more uniform and grain grew lamellarly.while in the process of temperature increasing from 250℃ to 300℃, the resistivity of GZO film didn’t change obviously.
With the temperature increasing continuously, grains began to become bigger and coarse, grain boundaries became wider and grain's surface roughness increased.

Meanwhile, grain refinement of metal powders, the increase of grain boundary area and atomic diffusion rate, alloying elements could spread to titanium matrix when sintering.
The grain boundary energy and distortion energy around the defects were high.
Thus within the grains accumulated a large number of microdefects such as dislocations and vacancies.
It further transformed into subnetwork, and eventually refined grains.
This is due to the high energy ball milling, and crystal defects in the material increase, the number of priority areas of new phase nucleation increases.

Meanwhile the sub-grain structure appears after several cryogenic treatments.
The stress concentration results in a large number of curled threading dislocations, dislocation loops or dislocation package.
In the case of constant lattice number, the lattices will shrinkage in volume.
In addition some original grains break into small grains, which are called sub-grains[4].
Firstly, after the second CCAT lots of fine phases precipitate in intra granular grains.

In this research, Taguchi analysis was used to determine optimal heat treatment for minimizing grain boundary carbide content with optimum hardness.
Determination of appropriate times and temperatures for a heat treating procedure that will achieve both low grains boundary carbide and austenite grain size can appear initially to require extensive, Taguchi analysis provides an effective means of achieving these goals.
Taguchi method incorporate orthogonal arrays to minimize the number of experiments required to achieve a given set of performance characteristics [10,11].
Salt weight decreasing in quenching solution has significantly increased carbide content in matrix structure and grain boundaries.
The variables affecting the carbide content and grain size according to their relative significance are the austenitizing temperature, quenching rate and austenitizing time.