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Due to toughening effect of residual nanoparticles in the remelting region of laser remelted nanostructured coating, grain-boundary strength is high and there are a considerable number of transgranular fractures, but the fractures in the remelting region of laser remelted conventional coating are basically intergranular fractures.
For ceramic materials, fracture mode of crystal grains is usually related to grain boundary strength.
As transgranular fractures need a large energy, grain boundary strength becomes greater, where crystal grains can easily go through transgranular fracture; on the contrary, the smaller the grain boundary strength, the more easily the crystal grains can experience intergranular fracture.
%Y2O3 nanopowder consists of nanoparticles with small grain sizes.
(3) Due to toughening effect of residual nanoparticles in the remelting region of laser remelted nanostructured coating, grain-boundary strength is high and there are a considerable number of transgranular fractures, but the fractures in the remelting region of laser remelted conventional coating are basically intergranular fractures

Introduction In a number of countries the neutron diffraction method is used on a large scale in solid-state physics and materials research.
Where the distribution of grain orientation is not random we are dealing with a texture.
In number of countries the neutron diffraction method is used on a large scale solid state physics and materials research.
Our project is concentrated to investigation the grain-oriented materials by means of neutron diffraction method.
The determined pole figures are used to calculate the coefficients of expansion Cl µν for expanding the ODF function into a number of generalised spherical functions.

Yin [4] studied the tamping effect of cold spraying by number simulation.
Borchers [6,7] studied the influence of continuous bombardment from sprayed particles on microstructure of the coating; the results showed that dislocation walls, sub-grain boundaries had been formed in the coating, and the grains even are refined via sub-boundary by dislocation propagation.
In the present work, work hardening effect generated during dynamic formation of Al-based coating on ZM5 magnesium alloy was investigated by combination of number simulation and experimental analysis; and microstructure of Al-Si coating was also researched.
Meanwhile, a large number of equated grains with approximate diameter of 0.3~0.5μm also be observed in the coating.
And with increase of micro-strain, the high density dislocation might convert to sub-grain boundary to refine the grains in the coating further.

With the increase of annealing time, the number and dimension of metastable phase decreased at the same time.
With the increasing annealing time, both the number and dimension of metastable phase in as-solidified microstructure were decreased, Fig.4.
The energy at grain boundary is higher for where crystal lattice is seriously distorted, so the diffusion activation energy is lower at grain boundary.
Therefore, the atomic diffusion at grain boundary is easier and faster than that inside grain, so, metastable phase at grain boundary has transformed to stable phase firstly.
With the increase of annealing time, both the number and dimension of metastable phase decreased in as-solidified microstructure.

Although a number of additions can be used to enhance the ductility, titanium is the most promising addition because of its wide application in wrought alloys.
The main influence of the titanium addition was in the reduction of the number of defects.
%Ti, the number and the size of the defects were reduced, as shown in Fig. 2b.
The grain size at the edge was smaller than that in the centre for the castings of all compositions.
Effect of Ti on the grain size of the Al-Mg-Si alloy solidified in the TP-1 mould.

%Mn strip had a quite large equiaxed grain zone, while other Fe-Mn strips mainly consisted of columnar grains grew from the surfaces.
No central equiaxed grains were formed, as shown in Fig.6(a).
A large number of substructures like the stacking fault and dislocation were observed.
There were only columnar grain zones within the Fe-11wt.
%Mn strip became smaller and columnar grain was more

In several previous studies on various metallic systems, this behavior has been attributed to a number of factors, including extrinsic processing artifacts such as porosity, insufficient bonding, and impurities [5], as well as to intrinsic microstructural factors related to deformation mechanisms, such as high density of lattice imperfections and small size grains resulting in a low strain hardening ability [6].
The micro grains that are present in bimodal materials are known to suppress crack growth and facilitate strain hardening as a result of increased spacing for significant numbers of dislocations to intersect with each other and consequently accumulate during deformation [20].
Addition to embrittlement via initiating crack growth, grain boundary segregation will suppress grain boundary sliding [25, 29], which is widely known to be a dominant deformation mechanism in nanocrystalline and ultrafine grained materials [30, 31].
First, the distribution of grains in the starting powder and second, grain growth during the degassing and QI forging steps.
As discussed in the introduction part, the large grains can increase strain hardening ability by providing enough space for significant numbers of dislocations to intersect with each other and consequently accumulate during deformation, and therefore enhancing the uniform elongation and ductility.

A possible process characteristics the total cutting contact AK which is calculated from the number of active grains Nakt and the single grain cutting contact AGK (Fig. 3).
The number of active grains depends on the geometrical contact length lg, the number of grains per grinding layer volume unit NV and the cutting area depth z.
Thus the number of active grains increases.
The number of active grains Nakt can be calculated with the approach of Lierse and Tönshoff (Eq. 1) [10, 11]: Nakt=lg∙NV∙c2+1NV∙c1∙ae+vftvc∙lg1c2+1 (1) with c1=43dg (2) c2=32 (3) NV=6∙Cπ∙dg3∙ρg (4) lg=ds2∙cos-1ds2-aeds (5) c1 and c2 are empirically deduced for a round grain shape by Lierse, dg is the grain size ρg is the grain density, C is the grain concentration and ds is the grinding wheel diameter.
The total cutting contact AK, which is the product of the number of active grains and the single grain cutting contact, rises with increasing infeed ae and feed rate vft and decreases with increasing cutting speed vc.

SEM experiment conforms that the average grain size of sintered body is less than 300nm.
A number of researchers have demonstrated superplasticity in several silicon nitride ceramics by applying the transient liquid phase[3,4], using ultrafine β-phase powders[5,6], or by adding secondary phases into Si3N4 to refine the microstructure[7].
Microstructures of as-hot-pressed materials are very fine and uniform, with average grain sizes about 300nm.
Alternatively, at constant stain-rate, the forming temperature can be decreased with smaller grain size.
Microstructures of as-hot-pressed materials are very fine and uniform, with average grain sizes about 300nm.

The number of grains, n, in the analyzed area is determined so that the resultant mean grain-size should correspond approximately to the size measured in experiment.
Schematic illustration of grain-structure and stress state in i-th grain.
Stress State in Modeled Grain.
The grain size d(i) of the i-th grain will be used as the slip-band length of the grain in the crack initiation analysis.
Employing three series of uniform random numbers, three distinct modeled microstructures composed of differently-shaped grains, which have distinct directions of slip-lines and slip-planes, are analyzed for one testing condition.