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To gain a more detailed insight into the influence of ECAP, we investigated the corrosion behavior of Al-Mg alloy with increasing the number of ECAP passes and compared them with their coarse grained counterparts.
The number of ECAP passes is 2 and 4, respectively.
With multipass ECAP, remarkable grain refinement occurs by repeated shear deformation, and the grains were refined to submicron level after four passes.
Meanwhile, high dislocation density within the grains can be observed.
Conclusions Corrosion resistance of Al-2.8%Mg alloy subjected to different number of ECAP passes were studied; and the results are summarized as follows

Especially, a large number of thin-wall covering parts are produced by the means of the sheet pressing.
It has been discovered that there are a great number of twins existing in grains of magnesium alloy sheets, which are deformed at 200~300ºC and warm-rolled by 15%, though rolling temperature is not too low.
The grain are uniform distribution equiaxed grain, average diameter 14µm (Fig.3a) and with high mechanical properties.
After 120minutes, some grains grow bigger.
If the annealing time period increases, some grains grow bigger.

A large number of blocky ferrite formed due to the increase of chromium level in the matrix.
The bigger secondary particles were mainly present at grain boundaries, while the smaller ones mainly distributed in grain interiors.
A large number of blocky ferrite formed due to the increase of chromium level in the matrix which can expand ferrite phase region.
It can be seen that secondary particles precipitated along grain-boundary and formed into chains in the steel tempered at 600°C.
A large number of blocky ferrite formed due to the increase of chromium level in the matrix.

The first part is star propellant grain, the second part is tubular propellant grain, and both ends of these parts have a stress reliever.
The total number of C3D10 elements is 61353, C3D8R elements is 364189 as showed in Fig. 3.
Mach number contours of fluid T=1ms T=4ms Fig. 6 b.
The Mach number of the fluid at different step times was studied.
The stress and strain of propellant grain were analyzed.

Figure 1 (g), (h) of ZK60 and ZK60 +1.0 Y morphology of two alloy extrusion products, we found that both alloys extrusion occurred after dynamic recrystallization, which ZK60 alloy extruded After the abnormal grain growth, and grain ZK60 +1.0 Y Y rare earth alloy added after the relatively small, large grains mixed with very fine recrystallized small grains, which is mainly due to the black alloy ZK60 +1.0 Y reticular formation of crystalline zinc-rich phase was squeezed after crushing second phase particles and fine particles, pinning grains and dynamic recrystallization grain growth inhibition dual role, it can effectively refine rare-earth Y alloy ZK60 tablets.
Figure 1 (e), (f) ZK60 and ZK60 +1.0 Y for the two-state microstructure T5 alloy extrusion products, extruded products after aging treatment, ZK60 alloy grain boundaries within the grains and particles are precipitation, the grain boundary more clearly, after ZK60 +1.0 Y alloy after aging treatment, the organization tends to be uniform, fine recrystallized grains have grown little tendency to precipitate particles number obviously.
In the extrusion process, the alloy, rare earth alloy, magnesium can play an effective role in the modification, i.e., refinement of the grain structure, so that the average grain size is reduced, since the number of grain boundaries depends directly size, therefore, the impact of grain boundaries on plastic deformation resistance of polycrystalline starting directly reflected by the grain size.
Figure 1 (g), (h) shows that adding the refinement of rare earth alloy Obviously, an increase in the number of grain boundary dislocations motion by the resistance increases, thereby enhancing its mechanical properties, extrusions aging treatment dislocations generated during extrusion, sub-crystalline alloy beneficial compounds dispersed second phase precipitation, aging can be on the basis of maintaining the tensile strength, yield strength of the alloy greatly improved, so ZK60 +1.0 Y alloy extrusion products should adopt the artificial aging treatment.
Effect of grain refinement on tensile ductility in ZK60 magnesium alloy under dynamic loading [J].

Statistical method means the number of samples must be sufficient to ensure the accuracy of results. β grain size and α lamellar thickness of as-cast Ti-6Al-4V alloy with different plate thickness were analysised.
Its grain size is coarse because of crystallization (Fig. 2(a)).
After the above steps, each β grain area can be measured (Fig. 2 (f)), which can be converted into grain equivalent diameter.
(b) (a) (e) (d) (c) (f) Fig. 2 Primary β grain specitic treatment scheme, (a) Grain metallograph;(b) Grain boundary depiction; (c) Grayscale conversion; (d) Binarization; (e) Image enhancement; (f) result output β grain size of cast plates with different thickness was analyzed by above mentioned method.
Fig. 3 (b) shows the relationship between average grain size and cast plate thickness. βaverage grain size is obviously influenced by cast plate thickness.

Simultaneously, the effect of number of passes during ECAP was also discussed in terms of the microstructure change.
Special attention was paid on the effect of number of ECAP passes on the morphology of semi-solid.
The total number of passes was two, using a Molybdenum disulfide (MoS2) lubricant in a pressing speed of about 1 mm/s.
When the temperature reaches to above solidous, the high-energy grain boundaries of these new grains are penetrated by liquid, leading to the fragmentation of original grains to small equiaxed grains.
The presence of liquid causes grain growth and spheroidization of the newly grains.

For quick references, the sample without bismuth ions was denoted and the samples with increasing concentrations were numbered from “1”, “7”.
The microstructure parameters are ASTM grain size (G) and porosity (P).
The undoped sample (“0”) have a relatively uniform microstructure with relative uniform grains and the density is 4.68 gcm-3; at low Bi2O3 contents (<0.03 wt %) the structure becomes fine-grained and more uniform and the density greater than 4.80 gcm-3; an abnormal grain growth is observed for sample with 0.07 wt % Bi2O3 which density was 4.74 gcm-3; beyond this doping level the samples show a well crystallized microstructure with large grain size, and the 4.83 gcm-3 density.
Fig. 4 Loss factor as a function of ASTM Grain Size and Porosity.
At 0.5 wt% doping level, the segregation of Bi2O3 on the grain boundary and intergranular pores hinder grains growth so the average size decreases.

The grain size determined from Electron Backscatter Diffraction (EBSD) maps indicate the reduction in average grain size with individual Ca and Ce additions.
The literature has only a limited number of works on squeeze casting of AZ91 alloy containing Ca and Ce and it needs more attention.
A straight line was drawn in a specific location which intersected a bunch of cells all of which were arranged in a row, and the number of cells was calculated by dividing the length of the line.
Grain refinement in AZ91-1 wt.% Ca and AZ91-1 wt.% Ce alloy The average grain size was determined with the help of EBSD analysis.
Also, Al2Ca and Al11Ce3 intermetallics are pinned at the grain boundaries and restrict the grain growth.

Vanadium addition promoted the precipitation of carbides both in ferrite grains and at its grain boundaries.
Angular carbides were also found in other vanadium alloyed specimens but the number of dot-like carbides decreased with the increase of chromium contents.
On the contrary to as cast specimens, vanadium alloyed specimens having higher chromium contents after annealing had a large number of dot-like carbides in ferrite grains.
Fig. 3 Grain sizes of annealed specimens.
The addition of vanadium promoted the formation of angular carbides in ferrite grains and at its grain boundaries.