Search results

It can be found that, small-size (< 10 nm) grains, together with pores in grain boundaries, aggregate at the boundaries of larger grains.
Moreover, pores in grain are easy to be observed.
For nano-grained polycrystalline ceramic, both lower grain scattering and lower pore scattering result in high Fig. 3.
However, for nano-grained polycrystalline ceramic, both lower grain scattering and lower pore scattering result in high transparency..
Acknowledgements This work was supported by NSFC of P.R.China under grant number 50272040, Fok Ying Tong Education Foundation under grant number 91046, and Youth Science and Technology Foundation of Sichuan Province under grant number 03ZQ026-039.

Grain Size Wire specimens were produced using different deposition methods and measured under XRD for their grain size.
Variation of grain sizes with pulse plating duty cycle.
Herzer [2] analyzed that in ferromagnetic materials with grain size, larger than the exchange interaction length, the magnetization can follow the easy magnetic directions in the single grains and domains can be formed within the grains.
As a consequence, the effective anisotropy for the magnetic behavior is an average over several grains, N K Ke 1 = (4) where Ke is the effective anisotropy and N is the number of grains included by the exchange interaction length, 3 )/( DLN ex= (5) where D is grain size.
At duty cycle 50%, the grain size was found to be the smallest.

It confirms the aforesaid and also existence of a large number of twins in the structure.
Thus, the initial structure of the 08%C-18%Cr-10%Ni-Ti steel is a typical coarse grain austenitic structure (∼ 85%) with a large number of twins as shown in Figure 1.
The EBSD observations after ECAP at room temperature revealed a mainly grain structure (fraction of HAB ∼ 59%) with an average grain size of 410 nm (Table 1).
The fraction of high angle boundaries is ∼54% and the average grain size is ∼ 940 nm.
So the size of subgrains is almost half of the grain size.

The second phase particles that precipitatesin the steel has a pinning effect on the grain boundary, thushinder the grain boundary migration and suppress the grain growth, for which, on purpose of grain refinement and improving material properties, the particles of the second phase are introduced into as an effective control method[5-8].
As can be seen from the picture, some strips wereon the internal grain boundary of theexperimental steelmicrostructure, which analyzedby EDS was main component of component C, Fe, Cr, while the matrix was also C, Fe, Cr, but the C, Cr peak is significantly higher of grain boundariesthan that of the substrate.
Grain boundary strip Matrix Fig. 4.
(2) Under the experimental conditions, the experimental steel also precipitated a rectangular second phase particles of (NbTi) CN phase and TiC, which were sparsely distributed with the size of 100 ~ 300nm and below 30nm, while some phases were distributed as a number of strips in the grain boundary which mainly are C, Fe, Cr.
New Ultra-fine Grained Weathering Steel in Grade of 450 MPa, J.

We can see that its microhardness numbers, ultimate stress and tensile strain-to-fracture value grow with the degree of deformation (Fig.2) or a number of multigrains generated in the SPD processed SHS intermetallic compound.
The figures stand for grain and interlayer size, respectively.
The microhardness numbers of SHS intermetallic compound Ni3Al as depended on the SHS process type.
The effect of grain size on the yield strength of Ni3Al//Acta Met. -1985.
Producing Bulk Ultrafine-Grained Materials by Severe Plastic Deformation.-2006.

Nucleation of eutectic cells is modelled using an Oldfield-type nucleation model where the number of nuclei in the melt is determined by the amount of active nuclei and the local undercooling from the surface to the centre of a plate casting.
Eutectic grains are modelled as spheres growing between the dendrites.
The number of eutectic cells per m3 formed in each time step is calculated in each element using Eq. 3.
Taylor, Three-dimensional analysis of eutectic grains in hypoeutectic Al-Si alloys, Mat.
Dahle, Aluminium phosphide as a eutectic grain nucleus in hypoeutectic AI-Si alloys, J.

Fig.1 Schematic diagram of axial ultrasonic honing Fig.2 Velocity diagram of the oilstone Grain distribution on the oilstone surface The distribution of grain is random on the oilstone surface, so the size and distribution situation of grain will directly related the honing force, honing heat and the workpiece surface quality.
According to the volume fraction ω and mean diameter of grain, the average number of abrasive per unit area can be estimated as Eq. 2:
Force model of single grain with ultrasonic vibration In the ultrasonic honing process, the material was enabled to be chip and removed through the interactional function of rowing, ploughing and cutting between grains and workpiece.
Assuming the grain sharp to be cone with a flat-topped (Fig.5), the honing force involved in chip deformation force and friction force of single grain can be represented as Eq. 3:
(11) (a) Schematic of instantaneous velocity of oilstone (b) Schematic of honing force Fig. 6 Schematic diagram of velocity and force in ultrasonic honing process Where, is the total number of dynamic effective grains contacted with the workpiece on the oilstone surface; is the half-angle of honing checker in the ultrasonic honing process; m represents the mass of oilstone and oilstone seat.

It is also well known that in most of the ultrafine-grained metals and alloys decreasing the grain size below 1 mm leads to significantly reduced ductility due to a decrease in the work hardening capability [3,4].
This way, additional work hardening effect i.e. improved ductility can be produced due to increase number of geometrically necessary dislocations on the boundaries between fine and coarse grains.
Hodgson, Study of the grain size effect on the deformation behavior of microalloyed Steels, Proc.
Minamino, Strength and ductility of ultrafine grained aluminum and iron produced by ARB and annealing, Scr.
Majta, Study of the effect of grain size on the dynamic mechanical properties of microalloyed steels, Mater.

The concentration of the grain boundary corresponds to the number of atoms existing on the grain surfaces with a diameter of 16 μm, which is slightly larger than the block boundary of F82H [18].
The defect is related to grain boundaries.
Acknowledgement This work was supported by JSPS KAKENHI Grant Number JP18K03584.
Henderson Brown, Dislocations in grain boundaries and grain boundary sliding, Acta Metall. 15 (1967) 857–860
McLean, Changes produced by deformation in grains and grain boundaries of nickel, Met.

A digital image is composed of a finite number of elements, each of which has a particular location and value.
The alignment of the grain formation confirms the directional component of the grain growth for the sub merged arc welding process.
Total Grains in the Image Area of the Grains Area of the Total Image % Area of Grains 195 1.0167e+004 1.3873e+005 6.8281% No. of Grains Area of Grains (in terms of pixels) Figure 7 - Bar Chart representing distribution of size and area of Grains.
The grains are predominantly of smaller variety and the counts for larger grain are almost negligible as it is reveled in the bar chart (see Figure 7).
The grains are predominantly of smaller variety and the counts for larger grain are almost negligible.