Search results

Morphologies are fragmented and a large number of clusters of globular cells or dendrites are distributed in a cross section.
Indeed, the solute layer developing around the grains is of the order of the spacing between the grains.
The same methodology was used for modelling the columnar grains and the equiaxed grains.
The output of the CA model is the grain structure.
It should also be said that the grain structure model only considers the formation of equiaxed dendritic grains: no globulitic grain with a high inner volume fraction of solid is taken into account.

The basal texture is enhanced during sintering by selective anisotropic grain growth.
The increasing number of papers, based on this methodology, illustrates the interest of many researchers in materials science for Rietveld texture analysis [13-17].
As mentioned above, the number of points results from a selection with a criteria of confidence index (CI>0.01), in order to optimize the accuracy of the indexing selection.
However, while about 3×109 grains were involved in the neutron analysis, EBSD measurements on the polished surface covered at most 10000 grains.
Further experiments must however be performed for increasing the number of points and improving the accuracy of the analysis.

The second order stresses characterize the deviation of the stress in a particular grain from the first order value.
On the grain-scale, plastic deformation occurs due to the dislocation slip on crystallographic planes.
The second term of Eq. 3 describes the interaction stresses created due to differences between the sample and grain deformation rates (incompatibilities of grains with the surrounding aggregate).
We can see that the maxima of ODF correspond to the lowest or medium values of grain stresses, while the highest stresses are found for some orientations related to low number of grains (low values of ODF).
Low incompatibility stresses are generated in grains having preferred orientations.

The increase in number density and volume fraction are associated with precipitation of new particles.
The low magnification image shows constituent particles decorating the boundaries of a grain.
Within the grain, the dispersoids can be seen to have precipitated, with a relatively wide dispersoid free zone adjacent to the grain boundaries.
Figure 5 (a) shows the predicted number of excess vacancies (introduced by deformation) relative to the number of thermal vacancies and the predicted dislocation density as a function of strain rate at 500�C.
Above a strain rate of approximately two, the number of deformation induced vacancies is predicted to exceed the number of thermal vacancies.

Grain modifiers influence on the amount of nucleating particles.
This master alloys contains a large number of boride particles, which have effectively nucleated a grate number of aluminum crystals.
This effect have influence on the grain size.
This has been well demonstrated in a number of the aluminum alloys with Ti and B modifier.
The number and size of silicon particles in Al-Si alloys can by controlled by the same way like the size of the dendrite and size of the grain.

The results show that the alloy has the grain size of 42mm, straight of grain boundaries, intragranular no significant defects after solution heat treatment at 1063K. 
Figure 1 (a) is for the specimen with solid solution state, showing polygon equiaxial grains with average grain size of about 42 um measured by transversal-line method.
Irregular shape, fine grains with average grain degree of 1 um have the deformation flow lines (shown in arrow shown) in grains, which can be seen in Figure 1 (b) for specimen with the rolling deformation of 92%.
The intensity of {hkl} diffraction line is different for specimens with texture or without texture and intensity difference reflects the number of diffraction planes parallel to sample surface. 
Grain size of sample with solid solution state is 42um, the grain boundary is straight, no obvious defects are in crystal. 2.

Dpor: diameter of pores measured starting from fracture topography to avoid the artefacts related to polishing (pull out of grains).
Ceramics F and H contain cordierite (Table 2) and have, a priori, a high interface number, thus more traps what leads to a high breakdown strength (14.9 and 14.4 kV/mm).
In the case of ceramics B, in spite of the high number of interfaces, the nature of inter-granular phases, without cordierite, probably leads to other types of interfaces which decrease breakdown strength (13.9 kV/mm).
Indeed, strong breakdown strength at room temperature can be related to strong capacity to trap charges at interfaces localized in the grain boundaries.
At the first steps of wear (low load, short time), the dielectric phenomena seem to have a significant role on the fracturing of alumina grains.

Grain coarsening occurs at the deformation temperature close to γ′solution temperature, and the grain grows up obviously with decreasing strain rate.
Comparing of PM process, Spray forming can keep the advantage of rapid solidificationmicrostructure characterization with fine grain size, more uniformly distributed precipitates in the matrix, eliminating macrosegregation and reducing microsegregation of alloying elements[6, 7],in addition, lower the cost of products by reducing the number of process steps.Hot deformation is important for spray formed superalloy to improve the properties.
Some pores distributes were observed on the trip-grain boundary( Fig 1a).
Increasing temperature to 1100℃, fine dynamic recrystallization grains appear around large grains, revealing necklace microstructure (Fig.3b).
When the alloy deforms at high strain rate and temperature lower than γ′ solution temperature, γ′phase and carbides in the matrix will restrain the growth of the dynamic recrystallization grain, avoiding grain coarsening[8]. most of γ′phase will solute into the matrixwhen hot deformed close to γ′ solution temperature, the increasing of grain boundary migration during dynamic recrystallization process favors the growth of grains resulted in the grain coarsening[9].

The electronic charges in grain boundaries and grains are compared with each other.
It is well known that ceramic materials are comprised of grains, pores and grain boundaries.
When the grain size remains the same, the creep resistance is determined by grain boundary sliding which is controlled by grain boundary characteristics [6, 7].
Where, the optimization convergence standard is Fine, the energy deviation is 10-5eV/atom, the kinetic energy cutoff value is 340eV, the precision of self-consistent field is 10-6eV/atom, the number of empty bands is 20 and the k-point count in reciprocal space is 6×4×1.
Si-O at grain boundary and Al-O in grain is the weakest.

Appropriate plane slots number of the container yard is of great importance to the sustainable development of low-carbon container ports.
The calculation of plane slots number of container yard has always been one of the key problems for container port.
Reasonable slots number and yard layout can save land resource as well as improve the port productivity.
Therefore, the optimal storage yard space is 230 TEU per 10000 TEU throughput and the corresponding plane slots number is 51.
Wang, Container terminal operations to receive payment amount and the yard area of research, Grain Processing. 12 (2010), 74-76