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The grains of ECAP are further refined to 6μm.
For ECAP precessed sample, grain boundary sliding happens and the proportion of high-angle grains are improved, which makes grain boundary sliding easier.
It is because that the number of enabled slip systems are few and only slip systems on basal plane is completely activated.
Grain boundary belongs to defects essentially.
While for ECAP, the enhancement of high-angle grain boundary contributes to the grain boundary sliding.

This technique opens for studies of both overall grain growth as well as the growth of individual grains.
Due to the submicron grain structure after ECAP, and since the XRD experiments were to be carried out in a Laue transmission geometry, even thinner areas had to be made (~100-200 µm) in order to reduce the number of diffracting grains and to be able to treat them individually.
In-situ grain growth studies.
Note that the degree of rotation around PD varies from grain to grain.
Grain growth kinetics.

It is shown that the simulations can correctly reproduce the softening effect linked to a decrease in thickness and in number of grains across the thickness: the quality of the final shape strongly depends on the number of grains across the thickness.
For dimensions larger than a few micrometers, these modifications involved by miniaturization are due to a decrease in the number of grains across the thickness (also called thickness to grain size ratio, t/d ratio).
(a) Barkhausen noise in plastically strained Nickel with two different grain sizes [6].
Optimization of the mechanical properties of this product is typically a size effect because of the very small dimensions of the IMC interlayer and the weak number of grain through thickness for copper external layer.
Geers, An experimental assessment of grain size effects in the uniaxial straining of thin Al sheet with a few grains across the thickness, Mater.

It can be seen that refinement effect is increased with the rising of the pass number.
When the pass number is 12, the refinement effect of grains is not obvious, but the microstructure is homogenized.
Most of the grains size is about 6μm, some small grain can reach 2 ~ 3μm.
(2) The refinement effect is increase with the rising of extrusion ratio and the pass number.
When the pass number exceeds 8, greater pass number does not make grain refinement more obvious, but it makes the grain more homogeneous.

In the EBSD grain boundary maps, green lines and red lines show high angle grain boundaries with misorientation angle (q) larger than 15° and low angle grain boundaries having misorientation 2°≤q<15°, respectively.
The mean grain sizes of the specimens are 40 µm ~ 50 µm.
The average grain size of the specimen deformed at 100 s-1 is 10 µm, which is a fairly fine grain size.
The mean grain size (thickness) is 200-300 nm.
The equivalent strain determined by equation (2) becomes much smaller than Hencky strain at high strain regions, so that Hencky strain rate decreases with increasing rotation number in the present torsion test using constant rotation speed.

Considering the accuracy and efficiency of simulation, the total number of elements, nodes and sample surface polygons were 100500, 14117 and 19330, respectively.
The average grain size is about 43 μm.
After three CGP cycles, grains become finer and the average grain size is about 10 μm.
The grains of 5052 Al alloy can be refined significantly by CGP or UGP, but the processing conditions affect obviously the rate of grain refinement and the final grain size.
The CGP has higher rate of grain refinement and finer grains than that of UGP

EBIC Study on Metal Contamination at Intra Grain Defects in Multicrystalline Silicon for Solar Cells T.
However, mc-Si includes numerous defects, such as grain boundaries (GBs) and intra-grain defects that act as minority carrier recombination centers.
Up to now, grain sizes have been enlarged to improve conversion efficiency by reducing the impacts of GBs [4-6], and grain become larger than the minority carrier diffusion length.
The small angle grain boundary (SA-GB) is one of the intra-grain defects with strong gettering abilities and act as minority carrier recombination centers [8, 9].
The numbers with arrow on the dark lines indicate misorientation angles at SA-GBs.

Grain boundary velocities are calculated from the fluxes of vacancies to grain boundaries.
Atomistic models can account for fine details in systems, but these methods are not yet feasible for simulating many industrially relevant interconnect structures due to the vast number of atoms involved, e.g., on the spatial and temporal scales needed to interpret reliability studies on test structures.
The model accounts for grain structure, including the orientations of the individual grains, their mechanical anisotropy and the effect of grain boundaries on the redistribution of vacancies with the grains.
Here the <100> grain is growing at the expense of the <111> grains.
The fastest-moving grain boundaries in the system are those along the <100> grain.

Ultrafine-Grained HSLA Steel Processed using MAF: Dry sliding Wear and Corrosion Behaviour Aditya.
Submicron sized grain size was obtained after warm MAF.
It shows equiaxed ferrite grains with banded pearlite colonies.
In general, materials with higher grain boundary densities exhibit higher wear rates than those with lower grain boundary densities or single crystals.
Lee, Effect of the number of ECAP pass time on the electrochemical properties of 1050 Al alloys, Mater.

Its objective is to modify materials performance by designing and controlling grain boundary character distribution (GBCD) through a thermomechanical processing [1].
Grain boundaries with 1≤Σ≤29 were regarded as special coincidence site lattice (CSL) boundaries, and Brandon's criterion was applied to determine the Σ number for all boundaries.
Accompanying by the formation of high frequency low Σ CSL boundaries, the continuous random grain boundary network was extremely dispersed by introduction of low energy segments on migration random boundaries during twin emission and boundary-boundary reactions in the grain growth, see Fig.4.
Random grain boundaries and low ∑ GBs indicated by black line and gray line, respectively.
In fact, IGC propagates along GBs from the surface into the interior of materials and leads to mass-loss caused by grain dropping.