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There are a number of the black impurities in the bonding band and joint interface, and the interface is a “virtual bonding” state.
New “necklaces” grains are formed around the grain boundaries and the impurities in the band and the band width have been almost disappeared.
Thus, the dynamic recrystallization is carried out fully, and a large number of co-grains are produced on the interface.
Meanwhile the interface grain boundaries produce a large number of dislocations and other defects, which reduce the diffusion activation energy.
When the press quantity reaches 125%, as shown in Fig.9 (e) ~ (f), it can be seen that oxide is broken clearly and the number of dimples increased dramatically.

Introduction In the production of metals and alloys, control of grain size is a key to improve the mechanical performance.
Adopting per unit area grain number represent grain size, A 100mm2 piece sample was sectioned along the center point, and calculated the ratio of 100 in the area of grain number, and the hardness and cooling curve is obtained via microsclerometer (HVS-1000) and temperature recorder.
When the pulse voltage is 700V, the sample is similar to 300V, the average grain size is 31/mm2.
The result agrees with the previous Fig.2; on the other hand, the platform shows grain growth time on the curve, the grain growth time is different depending on different pulse voltages, EPM is most effective on grain refinement when it is applied 500 V.
The result indicates the supercooling increased nucleation rate, the grain growth time is shortened in the meantime.

Microstructure of Ti was found to be refined to a grain size of about 0.4 µm due to formation of deformation-induced boundaries within initial grains.
Large deformation of hcp metal was studied insufficiently; meanwhile limited number of slip system operating and twinning can be key factors influencing on microstructure evolution in Ti.
Based on the EBSD analysis the number of grain boundaries with the misorientation higher than 15° (high-angle boundaries) increases with the strain from 10% after first increment to almost 70% at the end of the deformation (after Σε=6.2).
At small strains microshear bands and twins are observed within the initial grains.
On the each next step of deformation some dislocation boundaries scatter to a large number of movable dislocations decreasing yield stresses of the material (Baushinger effect) [11].

fragmentation of grains.
The microstructure of the SZ is characterized by fine and equiaxed α-Mg grains with an average grains size of about 2.5 µm.
However, both the number and the intensity of Mg5Gd-type phase diffraction peaks decreases considerably after FSP, indicating the significant dissolution of the Mg5Gd-type phase into the matrix.
The SZ was characterized by fine and uniform recrystallized grains.
The average grain size was refined to 2.5±0.9 µm (Fig. 4c).

Imagine a particular phase, with a very large number of grains in random orientations.
We then expect a large number of low angle boundaries between touching grains, and that will be reflected in the neighbour-pair histogram.
Time-lapse misorientation There are a growing number of in situ EBSD studies [17].
Given the number of minerals, there are likely to be many more relationships, and their effects may be cryptic.
There are a number of problems with this hypothesis, though.

The grain boundary can still be seen in the transition zone, and a lot of twin grain in different planes mutual settlement in the original large grains.
Original coarse grains of the matrix which are away from the surface is clearly visible, and little single-line twins are distributed among the original coarse grains.
Overall, the number of twins gradually decreased along the depth direction, but there is some heterogeneity, the corresponding grain size increases gradually along the depth direction, a continuous variational gradient is presented.
There are a small number of twins far from the surface layer (more than 250μm).
The grains strengthening may be caused by a small number of dislocation(Figure 1b).

Ferrite grain size is one of the most important microstructural parameters in steels which can be appropriately adjusted to cause a significant strengthening effect.
Thermomechanical processing is an effective method for ferrite grain refinement in microalloyed steels.
This is due to increased number of nucleation sites for ferrite phase, e.g. deformation bands within the austenite grains [9].
Fig. 3-B obviously shows one polygonal ferrite with approximate grain size of 10 μm, the most demanding phase in favorable microstructure. 3.
Specimen numbers are given in Fig. 2.

With this segmentation, we obtained statistics on macropores on intact and deformed Indiana limestone which shows that inelastic compaction was followed by a significant reduction in the number of macropores.
A number of isolated blobs (in red) can be identified in the macroporosity zone.
There is an overall decrease by a factor ~2 in the number of macropores with respect to the undeformed rock (Fig. 5).
The partitioning between solid grains, macroporosity and the intermediate zone dominated by microporosity are shown.
With this segmentation, we obtained statistics on macropores on intact and deformed Indiana limestone which shows that inelastic compaction was followed by a significant reduction in the number of macropores.

Yangtze River Drainage Basin Grain Size and POC component of suspended matter in lower Yangtze River Grain size and POC in Datong showed obvious seasonal change.
The controlling factors of the seasonal changes of grain size.
(2) Grain size controlled the POC%.
The upper reaches of the Yangtze River had strong physical erosion in flood season due to heavy rainfall, and brought a large number of coarsedetrital mineral[8], whose particle size is larger generally and more difficult to adsorb POC.
The grain size reduced.

The heat added to the metal causes grains to grow by absorbing smaller grains.
Grain Size, Microstructure and Surface Finish.
The grains in the HT+SR are much smaller and finer than the untreated sample grains, while the SAA grains are much larger and coarser in comparison to the untreated sample grains.
Table 3 shows the grain numbers and size gathered from each of the samples.
HT+SR Untreated SAA SR Sample ASTM Grain number Grain Size (um) No heat treatment 5.73 54.9 Stress relieved (SR) 5.42 49.3 Age hardened (HT+SR) 6.25 40.9 Fig. 2. 5x magnification micrographs of samples Table 3.