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The transverse austenite (sub)grain size was about 130 nm; and the fraction of high-angle grain boundaries comprised 0.7.
The numbers indicate the (sub)boundary misorientations in degrees.
The large lattice distortions associated with high internal stresses provide a condition for rapid nucleation of a great number of recrystallizing grains.
Therefore, these ultrafine (sub)grains can be considered as potential recrystallized grains.
The numbers indicate the (sub)boundary misorientations in degrees.

From Fig. 3, it is found that the introduction of O2:2% into N2 results in the decrease of grain boundary and the surface hole numbers.
The relationship of laser power versus grain size and average ablation numbers is described as followings.
It is clear found that the trap numbers (grain size) between grain boundaries are much higher in the gas environment of pure N2, but are greatly reduced in the gas environment with N2:98% and O2:2%N2.
It is noted that for laser power from 310mJ/cm2 to 360mJ/cm2, the numbers of grain size are obviously reduced for the case of N2:98% with O2:2%N2 under ELA recrystallization.
On the contrary, the numbers of grain size are increased while the laser power is over 380mJ/cm2.

However, the number of studies concerning the recrystallization and transformation behaviour in the conditions of fast reheating of cold rolled steel sheets with heating rates higher than 100°C/s is limited [3-6] and they consider the recrystallization of iron [6] or extra low carbon steels [3] after reheating with a reheating rate of 1000 °C/s [3] or 5000 °C/s [6].
The averaged grain size was evaluated on the base of the EBSD measurement considering as a grain each contiguous region with a misorientation of less than 5° and containing more than 4 pixels.
The grain size is strongly dependent on the reheating rate as it is demonstrated in Fig. 5 and Fig.6.
The dimensions of the largest grains are shown.
The grain size of ~1 µm is obtained in ultrafast reheated samples in the temperature interval 790-880°C but the question for grain growth in isothermal conditions after ultrafast reheating still remains to be investigated.

Precipitation of microalloy carbo-nitrides in austenite is used exclusively for ferrite grain refinement through an increase in the number density of nucleation sites for ferrite.
For the CR practice the increase in the number of nucleation sites results from the change in grain shape and the addition of active deformation bands and incoherent twin boundaries.
(a) (b) (c) 0 20 40 60 80 100 120400 500 600 700 800 Temperature, °C Number of grain boundary ferrite/100um or intragranular ferrite/100um 2 Intragranular ferrite Grain boundary ferrite acicular ferrite (d) Fig. 7.
Microstructure and number density of grain boundary ferrite and intragranular polygonal and acicular ferrite in 0.10%V steel isothermally transformed between 700-450°C prior to gas quenching to room temperature [13].
Quenching from 600°C produced a thin band of grain boundary ferrite and higher number of intragranulary nucleated polygonal ferrite crystals, Fig. 7(a).

Cold rolling flattens the original grains.
As there is no significant increase in the total number of particles, the solute is precipitated at already existing particles and their coarsening takes place.
The non-homogenised alloy, SV97, contains a number density of dispersoids that is five times greater than that in the homogenised SH97, which should give an appreciably higher Zener drag on moving grain boundaries.
These circumstances together with the observed similarity in the kinetics of precipitation and grain growth and the relative constancy in the volume fraction and number of dispersoids suggest that the precipitation of Mn during subgrain growth takes place by boundary diffusion to existing precipitates.
A pre-requisite for continuous grain growth to occur in these alloys is that the amount of cold work before annealing should be very high, which creates a large number of HAGBs.

Gamma Profile Analysis for Stress, Texture and Grain Size Bob B.
He Bruker AXS Inc, 5465 East Cheryl Parkway, Madison, WI 53711, USA Bob.he@bruker-axs.com Keywords: 2D detector, Residual stress, Texture, Grain size Abstract.
The g-profile contains information on texture, stress, and crystal grain size.
Each diffraction cone corresponds to the diffraction from the same family of crystalline planes in all the participating grains.
The number of candies to fill the box depends on the size of the candy and candy box.

The microstructure was effectively refined with increasing the number of CEC cycles as the grain size was reduced from ≈250µm to ≈30 µm after 6 cycles of CEC.
Microstructure Analysis Coarse equiaxed grains with ≈250 µm grain size were observed in annealed specimen, Fig.3, which represents the initial condition samples for CEC.
With increasing the number of cycles the macrohardness increased with a lower rate up to 6 cycles reaching about 2 times the hardness of the annealed alloy.
The improvement of the hardness value of the CECed samples is mainly due to the grain refining and work hardening in the material with increasing the number of cycles.
Summary · As the number of CEC cycles increases a more homogeneous grain structure with reduction in grain size from 250 µm to 25 µm

As the temperature is above recrystallization, some small cracks (or voids) formed along grain boundaries and slip deformation took place in many coarsened grains, while only extrusions and intrusions instead of obvious cracks or voids are observable for UFG Ti.
Experimental Procedures The UFG Ti and Cu rods with an average grain size of ~250 nm were produced by ECAP.
Simultaneously, some small cracks (or voids) initiated along grain boundaries (GBs) and slip deformation took place in many coarsened grains, as indicated in Fig. 1(c).
Analogously, the microstructures of compressed UFG Ti exhibited a somewhat decreased number of GBs than its initial states [10].
Notably abnormal growth of many grains occurred and the maximum grain size has got to more than 2 mm.

Grain size evaluation was performed using light microscope images and grain chord length measurements, samples of commercial WC-Co coarse and supercoarse grades being included into analysis for comparison purposes.
The international ISO 4499-1 standard recommends measurements of more than 200 grains; in the current analysis for each grade 561-924 grain chords have been measured on images of five fields.
Statistical (left) and geometrical (right) distributions of WC grain chord length in Co sintered carbide grade.
Statistical (left) and geometrical (right) distributions of WC grain chord length in NiMo2 sintered carbide grade.
Acknowledgements The article is based on the research project financed by NCN, project number 222/B/T02/2011/40.

This result indicates better crystallinity and structural ordering of ZnO in the grain and grain boundaries.
The reduction in breakdown voltage can be clarified by the increment in the average grain size after the sintering process, thus reducing the numbers of grain boundaries between the electrodes and causing the reduction ‘p-n junctions’.
The V-I nonlinear behavior of the ZnO disc is a phenomenon of the grain boundaries between semiconducting ZnO grains.
The breakdown voltage of varistors is directly proportional to the number of grain boundaries per unit of thickness and inversely proportional to the size of ZnO grain.
This reduction results from a very high growth of grains in the ZnO nanoparticles after sintering, which decreases the number of grain boundaries between the ZnO grains, thus reducing the potential barrier.