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The Zr-rich cores were believed to play an important role in grain refinement.
However, it cannot restrict grain growth during homogenization treatment at 520 ℃, and completely loss the grain refining effect for extruded alloy sample.
It would be desirable to have large density of dispersed nano-particles in alloying liquids without aggregation and growth during the solidification, which would be in favor of grain refinement and bring about dispersion strengthening effects.
The more bright somewhere in Fig 1 is, the more Zr content it implies, because of the higher atomic number of Zr than that of Mg.
With respect to 100MPa of as-cast pure magnesium, ultimate tensile strength of the alloy can raise to 140MPa when the Zr contents ranges from 0.4% to 0.6% due to the dispersion strengthening of Zr particles and grain refinement.

However, only a limited number of studies have been carried out on SSM cast aluminium alloys.
The equiaxed grain with primary α-Al and eutectic phases of the base metal is clearly observed.
The α-Al phases are globular with grain size between 30 to 160 µm.
The equiaxed grains and eutectic phases disappeared.
Finer grain structure is obtained in the SZ welded by the cylindrical pin.

.-2 grain size of about 10nm are dispersed in amorphous matrix.
With increasing irradiation time, the size and number of the precipitates increase.
Salt and pepper contrast typical for an amorphous structure can be seen between each nano-crystalline grain.
The nano-crystalline grains are embedded in the residual amorphous phase.
The crystalline grains are randomly oriented in each region and an amorphous phase remains in the matrix, indicating that nano-crystalline grains are formed with a nucleation and growth mode.

The HAZ region of Monel alloy revealed the grain coarsening in the adjacent area of the weld zone.
The grain boundaries in the epitaxial growth zone were well matched with those in the base metal.
Whereas the HAZ area adjacent to the base metal was fine grained HAZ (FGHAZ) led to high hardness.
The reason for this trend of micro hardness in the HAZ of all the joints was that the area adjacent to the weld/fusion zone experiences relatively slow cooling rate and hence has coarse grained microstructure, whereas the area adjoining the base metal undergoes high cooling rate due to steeper thermal gradients and consequently has fine grained microstructure.
Mela, Journal of Failure Analysis and Prevention Volume 4, Number 6, 44-50 [7] Alber A.

The corresponding numbers were denoted as No.1, No.2, No.3 and No.4 respectively.
From these photos, it can be seen that unique grain-refining feature of laser cladding attributed to rapidly heating and cooling result.
In order to estimate the changing of grain size, the full width half maximum (FWHM) of the strongest peak about Fe-Cr phase and γ-phase.
In this study, although Hall-Petch equation formula can not be used to accurately calculate the grain size of coating, the variation of FWHM also shows the changing tendency of grain size.
It can be seen that the grain of austenite is increased with the addition of chromium nitride, the grain of ferrite phase shows the opposite tendency when the amount of chromium nitride is not more than 15%.

Apparently, the white lump grains are uniformly enriched in the coating, which is depicted as point A in Fig. 5(b).
A large number of nanocrystals distributing in the amorphous matrix makes good contribution to the high hardness.
It can be found that the size of grains close to the substrate is bigger than the grain close to the surface of coating in second layer.
It can be found that the third layer was bright without obvious grains, illustrating that the high volume ratio of amorphous matrix is near the outer layer.
Otherwise, the grain size close to the substrate is bigger than the grain size close to the surface of coating.

Direct hot rolling of thin slabs may be followed by a well defined cooling pattern to produce fine-grained HSLA steel or multiphase hot strip on the runout table.
Thus productivity depends on slab-width and -thickness, casting speed and number of strands.
The number of mill-stands determines the minimum final thickness that can be achieved, in particular when higher strength levels are requested.
However this has no relevant grain refining effect [10].
Microstructures up to grade X80 exhibit uniform, fine grain sizes all over the strip thickness among with good mechanical properties, including notched-bar and DWTT toughness tests down to -60°C [7, 8].

The GMs and composite GMs were prepared from self-adhesive carbon grains (SACG) of oil palm empty fruit bunches and SACG added with 2 wt.% of multi-layers graphene, respectively.
These GMs are designated as 18GM-0, 18GM-2, 36GM-0 and 36GM-2, where the numbers used refer to the weight percent of graphene and milling time.
The 18ACG-2 cell shows the longest discharge time compared to other cells; an evident of larger number of electrolyte and electronic charges entering/leaving pores of electrodes during charging and discharging.
Harun, Young’s modulus of carbon from self-adhesive carbon grain of oil palm bunches, J.
Alias, Electrical and mechanical properties of carbon pellets from acid (HNO3) treated self-adhesive carbon grain from oil palm empty fruit bunch, J.

Introduction Biodegradable foamed polymers and composite materials are ecologically and commercially promising primary products or raw materials for environmental and agricultural applications [1, 2], which can be characterized by a number of methods illustrating both quantitative and qualitative differences between the roles of the porous structure in abiotic and biotic polymer degradation [3].
The fillers used are finely dispersed, do not dissolve in the polymer, increase the number of defects in the matrix, thereby lowering the resistance of the composite materials to physical and mechanical stress [73].
According to a number of works [83-85], the presence of 15 - 30 wt.% of the natural filler in a composition with a synthetic polymer is sufficient enough to ensure biodegradability of the latter.
t,°С The polymer composite behavior upon melting t,°С The polymer composite behavior upon cooling 35,6 Movement of the polymer mass begins 99,6 Polymer grains are formed 110,5 Transition to the liquid state 89,9 Movement of the polymer mass stops Official Dataset Source: Grigorieva, E. (2021, April).
Grain formation in the melting of the composite containing polyethylene with 5 wt. % of hydrocerol and 15 wt.% of the wood flour (fraction 0-200).

Due to this, during the elastic deformation of polycrystalline materials, there are very large differences between stresses loading of crystallites, which have different grain orientation.
Let us suppose that, the orientation of the grains is equally distributed from a statistic point of view, and the number of the grains is much higher than 30, which is the necessary factor for homogeneity.
avE σ ε= (2) The changing in the structure of some grains is equal with the value above mentioned.
It can be considered; that this is also a reason that in the BCC metals the number slip systems is the multiple of the slipping planes of FCC metals.