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Firstly it is possible to increase ductility with reduced average grain sizes, through the mechanism or grain boundary slip.
Hence it is necessary to strongly deform the available slabs in the rolling process which causes a high number of cost-intensive passes and heat treatments.
When defining the alloy specific rolling temperatures, numbers of rolling passes per heat and the heat-treatment regime it is functional to achieve a recrystallized, finely grained microstructure without predominant orientation, since further deformation (e.g. deep drawing) can thus be strongly improved.
The grain refinement takes place exponentially during the thickness reduction.
When the additional deformation mechanism of grain boundary slip occurs, e.g. in grain refined ZEK100, the formation of textures is strongly reduced as can be seen in the comparison between AZ31 and ZEK100 illustrated in Fig. 7 [6].

The number density of Mg/Si aggregates was about 7 x 1023 /m3 and the size of the aggregates was about 2 nm (see Fig. 3(a)).
For the peak aged condition, the atom probe analysis volume within the grains indicated a composition of 0.5at%Mg and 0.8at%Si.
The number density of particles was 4 x 10 23 /m3.
Atom probe analysis showed 0.4 at%Mg and 0.8 at%Si within the grains in reasonable agreement with the alloy composition.
Particle number density in this under-aged condition was 12 x 1023 /m3.

The grain size of the phases in each composition was 1-15 µm for Iron and Copper.
In order to represent the microstructure as realistic as possible, grains with the properties of Iron and Copper were connected to clusters of approximately 20-50 grains.
Furthermore the partition of grain nodes may be inappropriate (20-40 nodes in the grain interior and >380 nodes at the grain boundary) leading to a "rigid" behaviour of each grain during deformation due to a lack of sufficient degrees of freedom [13].
An improvement of the present RVE may be possible by the use of other element types, which are able to resolve more accurately the grain-to-grain interaction and the interior grain deformation [13].
Part of the work was sponsored by the Deutsche Forschungsgemeinschaft under contract number BE 1455/10.

The average crystallite grain size was evaluated to be around 19 nm with degree of crystallinity close to 48.3%.
XRD analysis of annealed SnO2 thin film Avg. crystallite grain size.
This result is in agreement with Jasim et al. [33] that grain size increases with increasing temperature.
Representation of various parameters analyzed through XRD Sample Number Avg.
The average crystallite grain size also get increased after the heat treatment (annealing).

The grain size is 150 ~ 250 meshes and its chemical composition are shown in table 1.
With the growth of dendrites into cladding layer, the alloy composition and temperature gradient of of crystal interface front micro area both change, which change the branches crystals grain size and growth direction, even change grain growth form.
In addition, according to the Scherer formula D=Kλ/Bcosθ can determine the cladding layer grain fine.
In the laser cladding process, the heat transfer speed is rapid, so it is formed that a large number of crystal nucleus, and the growth speed of nucleus of crystal is rapid, which led to the result that the intermediate microstructure of the cladding layer is not obvious and a large number of tiny dendrites appear in the direct microstructure of rules configuration.
And the movement of dislocation in grain boundary or the second phase boundary is hindered.

Mix characterization The mixture used in this study is decomposed into grains and paste.
Under these considerations, the specific volume of granular skeleton (Vs) and the excess paste thickness (δ pex) can be calculated by Eq. 3 and Eq. 4, where Ri and ni represent the radius of particles of class i and the number of particles per class i, respectively.
Table 2: Mix proportions for the aggregate mixtures for one liter sample Mix type Excess paste volume fraction (%) Calculated ratio of excess paste volume to total paste volume (%) Calculated average thickness of paste layer (μm) Calculated number of grains LP4-A2 10 25 41 31.1E+04 LP4-B0 14 32 58 29.7E+04 LP4-B1 17 38 72 28.7E+04 LP4-C0 20 42 89 27.6E+04 LP4-C1 24 48 105 26.4E+04 Experimental results and discussion Mixtures were tested by the slump cone recommended by NEN-EN 12350-5[9].
In this study, the elements of the two phase material are applied as fundamental elements that consist of an inner core representing 1) the aggregate grain which is covered by 2) a layer of paste.
On the contrary when the volume of excess paste is less than about 10%, grains are considered in direct contact while bonded by the void paste which fills the gap between them.

Based on a large number of preliminary experimental studies, the tool rotation speed and feed speed were selected in the range of 300 to 700 rpm and 40 to 90 mm/min, respectively.
This may be due to the grains are recrystallized and refined with the increment of feed speed when the temperature at 200 °C.
From another perspective, when the tool rotation speed is 700 r/min, the grains in the modified region under various feed speeds are larger which illustrates that the value of friction coefficient is higher.
Therefore, the grain refinement is not obvious and the wear resistance is not improved significantly.
Furthermore, when the tool rotation speed is too high, the heat generated by friction and deformation is too large, and the grains grow again after refinement under the action of heat.

Both alloys nearly showed a fully amorphous structure with only a small fraction of residual HCP Hf grains left after 50 h of milling.
Hence the number of Hf grains in the amorphous matrix is much higher for the mechanically alloyed powders than for the ribbons.
These Hf grains can serve as nucleation sites for primary crystallization, thus lowering the crystallization temperature.
However, a number of peaks cannot be assigned to any elemental or intermetallic phases of the Cu-Hf-Ti system, for which XRD data is available.
Sintering at 500 MPa results in a decreasing number of large-sized pores (see Fig. 6 (b)).

In order to understand the texture evolution in pure Mg and Mg alloys during plastic deformation, a number of experimental and simulation studies have been conducted [13].
Results The microstructure of the rolled AZ31 before test are shown in Fig. 1 and consists of fine and equiaxed grains with lots of twinning and shear bands and a mean grain size of approximately 20.8μm by the linear intercept method.
The deformation will rely on the grains that don’t obey the texture.
Twinning makes the orientation of grains in the twinning band change, and the basal deviate from the hard orientation.
So grains in the twinning band can satisfied the slip prerequisite.

The АFМ- images were processed by the visualization and analysis software Nova 873 Grain Analysis.
After homogenizing annealing, significant changes were determined in the surface, including those reflected in the primary recrystallization, which caused the formation of high-angle grain boundaries (Fig. 1 (b)).
For a membrane that has undergone homogenizing annealing (Fig. 3 (d)) flecking was not detected, but an increase in the number of grooves and microcracks along the grain boundaries was observed.
The annealed membrane is characterized by decohesion along the grain boundaries and a significant increase the number of inclusions of increased hardness (Fig. 4).
(а)- changes in grain boundaries; (b)- one of the grains in an enlarged scale.