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The present authors expect that ECAP would be effective in matrix grain refinements as well as enhancing matrix-particle bonding with an aid of shear stress which breaks surface oxides.
In particular, the effect of the number of ECAP passes was discussed. 2.
The grain size of the Cu matrix decreases mainly during the first two ECAP passes and is almost steady during further processes, similar to the saturating strain-hardening behavior with the number of passes in general ECAP data, although not shown here.
The decreases in matrix grain size and inter-particle spacing due to particle redistributions increase strength and strain hardening of the composite by decreasing dislocation mean free paths.
Hence, ECAP has one more viable industrial application; homogenization of microstructures of bulk composite parts in addition to grain refinement.

In these two conditions, pits are nucleated in grains and in grain boundaries, while in condition III (heating up to 1065o C during 1 h and air cooling followed by reheating up to 620o C during 24 h and again air cooling), pits are preferentially nucleated in boundaries of small grains.
In the as-received and treated material it is observed a reduction in the number of pits and increasing trend in the volume fraction of the artifacts, as Figures 2 (a), (b), (c) and (d).
These facts are mainly related with a number of anodic sites and anodic/cathodic area ratio variation during exposure period.
Conditions I and II, pits are nucleated in grains and grain boundaries, while in condition III, pits are preferentially nucleated in boundaries of small grains.
In these two conditions, the pits are nucleated in grains and grain boundaries, while in condition III, pits are preferentially nucleated in boundaries of small grains.

Texture evolution depends on the number and type of slip and twin modes active in each crystal.
Grain shape can evolve differently from grain to grain depending on their anisotropy and orientation and on average grain shape can depend on pass number and ECAE route.
Grain stress and interactions with neighboring grains change with grain shape, which in turn, impact grain re-orientation by changing the number and type of activated systems.
Depending on the route, pass number, and material, there are certain conditions in which grains are calculated to become severely distorted, for example, after three to four passes of route A [32].
The number below each pole figure indicates the number of ECAE passes and the letter indicates the route.

The homogeneous body was created by assigning to each element a random orientation created from random numbers.
We investigated the relationship between the number of elements and the mode of deformation.
However, the number of elements placed in the wall thickness direction differs from one to the other, depending on whether the centrally placed grains are almost convex or smooth.
Relation between number of elements in the thickness direction and deformation in the inner surface direction.
Acknowledgement This study was supported by JST SPRING, Grant Number JPMJSP2128.

In order to avoid the grain-size effect, the ECAP-processed alloy was annealed to coarsen the grains.
The ECAP implementation results in the formation of ultra-fine grained structure of the alloy with an average grain size of 2.0-2.4 µm.
However, at lower deformation temperatures, the plasticity of the alloy noticeably decreases because of a limited number of the effective systems of deformation.
The averaged grain size of the MA2-1 alloy for the different regimes.
The different routes of ECAP of the alloy result in the formation of ultrafine grained structure with an average grain size of 2.0-2.4 µm.

One calibration block was varied the grain size by annealing process.
The macrostructure, microstructure, grain size and grain orientation of weldment were analized by microscope.
The large grain size has high attenuation because of beam skewing and scattering at grain boundary [4].
From the microstructures of base material and annealing SDH block found that the grain sizes were number 9.5 (13.3 µm) and 5.0 (63.5 µm).
The grain size number of HAZ was 8.0 (22.5µm) that larger than grain size of base material.

The degree of formation of nanodomains depends on the grain composition.
Thus, a number of studies have been carried out on microstructures in piezoelectric materials.
This implies that localized stresses may have accumulated in the grains due to densification by sintering.
Fig. 6 DF-TEM images of domain structures in a grain of PZT ceramics fired at 1100 °C for (a) 1 min and (b) 2 h.
The degree of nanodomain formation could be sensitively changed by Zr/Ti ratio of the grains in the ceramics.

The macrostructure shows that samples with spheroidal and vermicular graphite show much smaller grain size than the flake graphite sample F.
This shows that, for a similar cooling rate, a larger number of austenite nucleus have developed over the same period of time per unit volume, suggesting that a greater nucleation rate of austenite characterizes the solidification of hypereutectic spheroidal and vermicular cast irons.
Two families of grains of different size are observed, as shown in Figure 2.
Some large grains having a size similar to that of gray iron sample F, and other much smaller grains.
A large number of colonies exist within a grain of the macrostructure, assuming that a grain is a portion of the volume having similar austenite crystal orientation.

Mean size of the grain is 20~30 [μm] which is smaller than the un-deformed area grain size see fig 3-d.
According to the grain size change, the small grain is the more capability to block the sliding.
The corresponding figures from the serial number in Figure5, table 2.
Grain refinement will block the grain to sliding and increase the yield limit.
According to the grain size change, the fatigue strength of the alloy has a relevance to the grain size.

To prevent abnormal grain growth, 0.25 wt% MgO was also added.
Influence of alumina grain size and volume fraction of SiC.
For alumina, the pullout dimensions increased with grain size.
around 2µm, and was independent of grain size.
Inspection of Fig. 2 suggests two sources of the reduction in grain pullout on adding SiC to alumina: (i) a reduction in size of each individual pullout, and (ii) a reduction in the number of pullouts present at any given time.