Search results

There have been a number of studies on the corrosion behavior of Si3N4 ceramics at high temperatures such as in molten salts and gaseous environments [2-4].
The as-received specimen shows a dense microstructure and consists of a mixture of small equiaxed and large elongated Si3N4 grains.
It can be seen from the microstructures of the specimens corroded for 0.5 and 1 day that the grain-boundary phase is selectively corroded away, clearly revealing the rod-like Si3N4 grains and resulting in a porous structure.
The diameter and length of Si3N4 grains are getting smaller as the corrosion reaction proceeds.
The as-received specimen shows only the β-Si3N4 phase, suggesting the amorphous nature of the grain-boundary phase.

(2) the distribution of grain sizes is rather broad, Fig.3a and b; the average area equivalent grain diameter d* in the flow plane TD of as ECAP-specimens is 0.16±0.04 om with a fairly large population of grains sized having less than 0.1 om dimension.
(3) a large number of low-angle boundaries (LABs) is visible in both OIM and TEM images.
This suggests that a large number of neighboring grains may be involved into crack tip plasticity, even near threshold.
It is therefore, unclear how plastic deformation can be transferred from one grain to the other and how dislocations in neighboring grains can interact with each other.
' The cyclic plastic zone is estimated to be considerably greater than the average grain size, and a possible explanation to this fact is supposed to be given in terms of the effective role played by the non-equilibrium grain boundaries for accommodation and transfer of plastic strain from one grain to the other via specific interface-related mechanisms such as grain boundary sliding.

Fine grained mortar (FGM) offers a new innovative technology binder system.
The innovative technique is achieved by using a small maximum grain size of 600µm for the mortars.
Studies of the used of FA as a cement replacement in FGM have been reported by a number of researches [14-21].
Fine Grained Mortar The speciality of FGM as compared to commonly used mortar is a mortar containing fine sand with maximum grain size 600 mm.
Then were ground by grinder with 1-3% retained on sieve number 325 (45µm) complying the requirement of ASTM C618.

The internal grains havealso been refined.
The edge grain of solidification ingot gradually shifted from the dendrite to the ellipsoid, spherical grain
In addition, under the atmospheric pressure with the same cooling rate, crystallization starts when the number of crystallization centers is little and when the line-speed is large.
Hence, the relatively coarse grains were got.
And the internal grains have also been refined

A number of hillocks on the film were formed after air annealing at 500 oC for 30 min and few things in N2 annealing.
Tin oxide films have been fabricated by a number of techniques, including spray pyrolysis, sputtering, chemical vapor deposition (CVD), and evaporation.
A cauliflower grain means an aggregated grain of crystallites, and the crystallite means the smallest grain with grain boundary.
However, if the grains of the film are composed of many crystallites as shown in figure 2, the migration of crystallites of a cauliflower grain is easier than that of one whole cauliflower grain because it needs less driving force or stress.
The standard specimen was sintered at 700 oC for 2 hrs and the grain size was about 200 nm.

The grain size was less than 1 μm via RPW process due to its severe plastic working on raw powder.
With increase in the number of cycles (N) in RPW process, the magnesium matrix grains are gradually refined.
The mean grain size at N=200 is 0.9 μm, and much smaller than that at N=1 (9.3 μm), that is, RPW is suitable for in-situ grains refinement.
On the other hand, when employing RPW at N=200, Fig.4 (b) indicates that fine β phases with 1~2 µm exist not only at the grain boundaries but within the grains.
UTS Fig.5 Dependence of tensile strength of H/E ZAXE05613 on number of cycles in RPW.

The reaction between the zinc plate (ZP) and the IF steel with near surface ultra fine grains (NSUFG) structure with grain size of about 89 nm was studied in temperature range of 473K to 623K in order to elucidate the temperature dependence of the reactions and its mechanism, by comparison with the reactions of ZP to coarse grains (CG) sheet, superficial cold rolled CG sheet (CG+R) and superficial cold rolled NSUFG sheet (NSUFG+R).
On the other hand, small number of nuclei are formed at small number of sites on the CG/ZP interface, and they slowly grow and take much time to connect to each other with limited mass transfer mainly by volume diffusion, resulting in the thin reaction layer in the shape like stone wall.
Thereby the cracks are yielded among the ultra fine αFe grains in the NS-UFG layer as shown in Fig.1c3-d3 and Fig.6b, and the ultra fine αFe grains are surrounded with the 1Γ -phase and/or 1δ-phase, and they become free from the αFe matrix just like a group of islands, after the grain boundaries are entirely covered with the 1Γ -phase and/or 1δ -phase.
By further annealing, the free ultra fine αFe grains decrease their size and number due to the dissolution to the 1Γ -phase and/or 1δ -phase.
Summary The reaction of zinc against IF steel with NSUFG structure with grain size of about 89 nm was studied in temperature range of 473K to 623K by using ZP on coarse grains (CG) sheet, superficial cold rolled CG sheet (CG+R) and superficial cold rolled NSUFG sheet (NSUFG+R).

The benefit of pc-Si is to make devices with large grain size.
The crystallized material is assumed formed by parallel single-crystalline grains, LG sized, separated by physically thick amorphous grain boundaries with a thickness of 1 nm.
Because of the complexity of the structure model and the limited number of points in programming language, only five perpendicular grain boundaries are considered here.
Density of States at the Grain Boundaries.
Also the potential variations are identical from one grain to another grain except the ones near the free surfaces or metal contacts.

In this paper, we compared four flip-chip LED devices with four different numbers of Au stud bumps.
However, when the number of Au stud bumps was larger than 24, the heat dissipation performance will become deteriorated due to the poor bonding between grain and substrate.
Fig. 5 shows the EL spectra of flip-chip LEDs with different numbers of Au stud bumps.
The current-temperature curves of non flip-chip LED and flip-chip LEDs with different number of Au stud bumps Conclusion This study has investigated the optimization of the Au stud bumps number for flip-chip LED.
However, the excessive number of Au stud bumps can lead to the poor bonding between the grain and the substrate, and thus affect the electrical resistance and heat dissipation characteristics.

Ti : C+N=12 Al-killed Steel Rimmed Steel Ti : C+N=6 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 Steel B Mean r- value Steel A Large Small Grain size Occurrence of Orange Peel Fig.5 Correlation between ASTM grain size numbers and mean r-values of cold-rolled steel sheets.
progress of recrystallization, where the <111>//ND grains increased and the <100>//ND grains decreased.
Therefore, the larger number of the <111>//ND recrystallized grains in Steel B, which nucleate in the vicinity of the hot-band's grain boundaries, can provide the large grain boundary area to grow into the deformed matrix even under the same migration rate to Steel A.
In the PFZ, little fine precipitates were not observed besides the small numbers of coarser precipitates.
Coarsening of precipitates on grain boundary relieves the pinning force and gives rise to the grain boundary migration.