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This was attributable to the formation of a high melting point Lu4Si2O7N2 grain boundary phase, which can be extensively grain crystallized during sintering.
Although Si3N4 grain shows slightly different thermal conductivity between a-axis and c-axis [10] (the c-axis corresponds to the grain alignment direction), the thermal conductivity of Si3N4 grain is much larger that that of SiO2 contained grain boundary phase [11].
Therefore, the ratio of Si3N4 grain and grain boundary phase in the material was key point for modifying the thermal conductivity.
Specific heat capacity, thermal diffusivity and thermal conductivity of the seeded and no-seeded Si3N4 ceramics Since the seeds addition and tape casting were employed in the fabrication process, the elongated Si3N4 grains grown from seeds were preferentially oriented parallel to the casting direction, resulting in both the number of grains per unit volume decrease and a decrease in the number of two-gain junctions [12].
The increase in number of the elongated Si3N4 and grain alignment was of benefit to the thermal conductivity.

Scheme of the grain configuration and original SE images of different regions in the Ni50.8Ti49.2 alloy showing the evolution of the Ni4Ti3 precipitates in size and distribution from the grain interior (GI) to the grain boundary (GB).
Ni4Ti3 precipitates in the GI region show a fairly random distribution with no regional preference for size or number density within the reconstructed bulk, while the precipitates in the GB region reveal a strong size variation along the slicing direction (Z direction), which is also the direction towards the grain boundary.
Number, number density, volume ratio and arithmetic mean of all listed precipitate parameters for the two selected regions.
The precipitates in the grain interior (GI) region with larger size but smaller in number show a fairly random distribution without any regional preference of volume or number density.
The smaller but large amount of precipitates in the near grain boundary (GB) region show an obvious decrease in size and significant increase in number when moving towards the grain boundary.

Each level grains the percentage of number or the percentage of quality is tested out.
Accumulative total that is smaller than each size number percentage or accumulative total quality percentage is surveyed out.
(2) The number of the particles at size between x and x + dx is dN: dN= N dyn(x)
Conclusions ·Ultrafine slag grains possessed very well self-similar.
Fractal characteristics of grains are appraised.

The rate-limiting step of this process is supposed to be boundary diffusion of solute along grain boundaries.
Moreover, beside DP and DC, GB motion is observed to be involved also in many other solid state reactions such as diffusion induced grain boundary motion (DIGM), diffusion induced recrystallisation (DIR), as well as grain growth [2].
Rapid evolution and grain boundary migration for dominating bulk diffusivities: =1 and =0.
The numbers “n” mentioned on each picture indicate the time sequence during the run such that: t= n*ifreq*Δt, where Δt =0.02 (in units of the phase-field relaxation time), and ifreq denotes the frequency of picture “emission” and varies from one run to the other (ifreq=2.104 generally).
Indeed, the grain boundary mobility also comes into play: a change in this quantity changes the geometry of the grain boundary and thus the “drag force” exerted by the attached grain boundary on the precipitate.

Mid-life stress amplitudes and the number of cycles to failure were exerted to calculate the cyclic stress-strain curve adopting the Manson–Coffin–Basquin and Ramberg–Osgood equations with respect to compatibility [6].
The average grain size (AGS) measured for more than 5000 grains varied only slightly between 0.7 and 1.6 µm depending on the Tp and CR reduction.
Blue grains = α’ -martensite DIM; yellow grains, coarse austenite (GS > 10 µm); green grains = medium-size grains (GS 3–10 µm); red grains = fine-sized grains (GS < 3 µm); black pixels, unindexed.
The reversion is fast and the grain growth minimal.
In Fig. 5, the stress amplitude vs. number of cycles to failure for annealed and cold-rolled Com-301LN and 690-60-56 structures was calculated from the strain-stress-lifetime data.

The results show that addition of only 0.20% Zr or 0. 20% Sc to Al-7.2Zn-2.2Mg-1.8Cu alloy can refine grains to a certain degree, and the addition of 0.10% Sc+0.20%Zr leads to stronger grain refinement, the average grain size is only 10-15μm.
When compound adding 0.20%Sc and 0.2%Zr, the average grain size is as fine as 20-45μm，and the grains is replaced coarse dendrites by fine equiaxed grains (Fig. l (d)).
Fig. 1 Optical micrographs of as-cast alloys treated by electro-polishing and anodization (a)Al-Zn-Mg-Cu (b) Al-Zn-Mg-Cu-0.2Zr (c) Al-Zn-Mg-Cu-0.2Sc (d) Al-Zn-Mg-Cu-0.2Zr-0.2Sc Fig. 2 Optical micrographs of as-cast alloys treated by keller's reagent (a) Al-Zn-Mg-Cu-0.2Zr (b) Al-Zn-Mg-Cu-0.2Sc (c) Al-Zn-Mg-Cu-0.2Zr-0.2Sc From Fig. 2, it is evident that the dendritic structure is coarse and a large number of second-phase particles exist within the grains and on the grain boundaries for the alloy with adding 0.2%Zr.
Zr and Sc compound addition in Al-Zn-Mg-Cu alloy could generate strong grain refine effect, fine equiaxed α-Al grain replace thick dendritic crystal. 3.
Grain refinement and superplasticity in 5083 Al[J].

At the beginning of the deformation, a large number of dislocations generated, glided and scrambled in the alloy, then entwisted to form dislocation cells, which were the recrystallization nucleus.
The average grain size is 20~30μm.
As the increasing of deformation, a large number of dislocations propagate, glide and scramble, so the deformation can keep going.
During the dynamic recrystallization, owing to the driving force, the grain boundary move and the recrystallization grain grows, when the grain boundary meet the primary γ’ phase, due to the pinning effect of the primary γ’ phase, the grain growth stop.
At the beginning of the deformation, a large number of dislocations generate, glide and climb in the alloy, then entwist to form dislocation cells, which are the recrystallization nucleus.

The films grow with granular grains.
The Ni33Fe67 film consists of irregular shaped grains and a few large triangular grains.
The Ni33Fe67 film consists of a large number of irregular shaped grains and a few large triangular grains.
It is attributed to the fact that a large number of defects such as vacancies, impurities and grain boundaries exist in the film compared with the bulk.
In general, a large number of defects existing in the film result in a low density of the film relative to the bulk.

With water-saving irrigation, the yield under N3 is more than that under N2, this is mainly contributed by the increase of the grain number per panicle and the thousand seed weight.
A significant increasing was found on grain number and seed setting rate in four nitrogen levels except the N4 treatment.
Under saving irrigation or traditional condition, effective panicles, grain number and seed setting rate was firstly increased and then decreased with the increase of N fertilizer (Table 1).
Water-saving irrigation was increased the average of grain number of primary rachis branches in less nitrogen (N0, N1, N2), but no significant different in treatment N3 and N4.The average of grain number of second rachis branches was reduced in treatment N1and N4 under water-saving irrigation, which indicated that less and more nitrogen both had impact on grain number of second rachis branches addition.
Zhai et al. showed that water-saving irrigation conditions could increase grain number, tillers, seed setting rate and thousand seed weight under the appropriate fertilizer.

Currently, most authors and researchers tend to favour on of the growth selection theories, in particular the Σ9 grain boundary theory, and a number of striking proofs for its validity have been presented.
In the case of Goss grain growth a number of specific theories on oriented nucleation and growth selection have been proposed.
The numbers in the fields correspond to the depth in the sheet.
Up to a temperature of 800°C, when still no abnormal grain growth is observed the numbers do not change significantly.
These numbers suggest that actually Σ9 boundaries do not show any increased mobility which would lead to a decrease of their density.