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Slope of grain.
Measurement of the slope of grain.
Mean density values ρm [kg/m3] and variation coefficient values CV [%] according to the grading criteria Number of accepted beams Criteria applied ρm CV [%] 45 (100%) None 680 10.04 40 (89%) Knots and slope of grain 679 10.28 35 (78%) Knots, slope of grain and insect attacks 685 10.24 Modulus of elasticity.
Number of accepted beams Criteria applied fm fm,k (5º percentile) CV 45 (100%) None 38 20 31.30 40 (89%) Knots and slope of grain 41 26 27.34 35 (78%) Knots, slope of grain and insect attacks 43 29 18.90 Strength class according to the results.
Number of accepted beams Criteria applied fm,k Eg, mean ρmean 45 (100%) None 20 13.565 680 40 (89%) Knots and slope of grain 26 13.976 679 35 (78%) Knots, slope of grain and insect attacks 29 14.484 685 Wood boring insect attack.

Besides, V2O5 addition changed its grain size distribution and resulted in some larger grains.
When the addition of V2O5 increased, the ratio of large grain rose and the distribution of grain size became broader.
Apparently both V and Zr elements were uniformly distributed inside the grains and grain boundaries without evidence of segregating.
This agrees well with the result that more number of larger grains were observed as listed in table 1.
(2) V2O5 with a low melting point can increase the number of large grains.

In this paper, we discuss about the influence of impurities on the grain growth during HPT and on the grain size reduction mechanism during SPD.
The limited grain growth reported upon annealing is usually attributed to the pinning of grain boundary by impurities.
Indeed, it has been reported that electrodeposited nanocrystalline Ni with a similar grain size of about 10-20 nm exhibits a significant grain growth during HPT [10, 11].
Measured compositions are given in the table (total number of atoms: 1.08 106) The three dimensional reconstruction of the analyzed volume is shown in the Fig.3.
However, it is for sure much larger than conventional grain boundary segregations observed along equilibrium grain boundaries [19].

The surface grains are gradually uniform, and the grain size is 2.1mm.
Most of them are still distributed in the grain, and the particles attached to grain boundaries and sub-grain boundaries also begin to increase.
Under the same process, the number of precipitates of 2# steel significantly reduces, and they are uniformly distributed in the crystal.
The higher the recrystallization rate is, the faster the volume number of precipitates grows
(2) The number of Cu2S and MnS in the precipitates is similar at the end of deformation.

The results indicate that hot corrosive gas mainly causes the strength reduction because of the degradation of grain boundary region.
It is thought that inorganic additives are reacted with SiO2 existing on the surface of each SiC grain at the sintering temperature and thus bonded with another SiC grains [5,6].
Table 2 - Characteristics of porous SiC filter Figure 3 plots strength as a function of number of thermal cycles on SiC plate filters.
Therefore the number of thermal cycle exactly means duration time at 850 oC.
Fig. 5- Strength of SiC plate filter Fig. 6 - Strength of SiC plate filter as a function of number of thermal as a function of number of hot shock cycles.

The numbering of the variants is proposed, as well as the misorientations between them.
Conversely, a method for calculating the parent hcp orientation from a sufficient number of inherited variants is proposed.
This limited number is due to the properties of the inverse orientation relation 1 g−∆ and the rotational symmetry elements of the hcp and tetragonal group.
Under this circumstance, a new analysis of the orientation relations and variant numbering must be made.
Lamellar colonies and Widmanstätten laths co-exist in a given grain.

The simulation results showed the impingement of arbitrarily oriented grains, and the grains began to impinge and coalesce the adjacent grains with time going on, which made the dendrite growth inhibited obviously.
Herein, noise was introduced by modifying the phase field equation (10) Where is a random number distributed uniformly between -1 and 1, and at each time step, is an amplitude of the fluctuations.
With the increase of time, the grains begin to coalesce and impinge the adjacent grains.
The competitive growth of these grains during solidification was observed.
The solute field distribution in different magnitude of anisotropy Conclusions The multiple dendrites growth showed the impingement of arbitrarily oriented grains, and the grains began to impinge and coalesce the adjacent grains with time going on, which made the dendrite growth inhibited obviously.

The nucleation model assumes that the grain density grows continuously with increasing undercooling.
The density of new grains at a given undercooling is given as follows: (7) ( ) * * S S L L L L S 1n C C C C V C k D D x y x y    ∂ ∂  ∂ ∂ − = + − +     ∂ ∂ ∂ ∂     * * S LC kC= * EQ * L L 0 L ( ) ( , ) T T C C m fΓκ ϕ θ = + − − 2 max 2 ( ) d exp d( ) 2( ) 2π N n T T n T T T σσ   ∆ − ∆ = −  ∆ ∆ ∆   (8) After the number of new grains in each time step is calculated, the location of these new grains is chosen randomly from among the remaining liquid cells.
EBSD technique is an effective method to reveal crystallographic structures and grain size.
The comparison of average grain size between experiment and simulation results is shown in Fig. 7.
They were in good agreement on grain size.

The grain boundaries were highlighted in 2(b).
Number 1 in the picture refers to grain boundaries and number 2 to some surface defects caused by the polishing process.
The orientation of the generated photo currents is perpendicular to the grain boundaries demonstrating the electrical activity of the grain boundaries.
As can be seen clearly the grain boundary below the indicated grain boundary in Fig. 6 (a) shows no electrical activity.
The top wafer of the corner ingot shows a higher strength of the measured magnetic fields and a higher number of electrical active grain boundaries in comparison to the top wafer of the center ingot.

When the solution temperature was close to the phase transition point (830 ℃, 820 ℃, 810 ℃), many sub-grains appeared inside the grain, which greatly reduced the average grain size but the uniformity of grain size was not at a good stage.
When the solution temperature dropped to 780 ℃, the average grain size was about 10 μm, the grains were small and evenly distributed.
This was mainly due to the large amount of deformation in the forging process and the large number of dislocation generated inside the alloy, which provides the locations for the secondary α phase nucleation.
The grains are small and evenly distribute. 2.
A large number of fine and dispersive secondary α phase precipitate in the grain after solution at 780 ℃ and aging at 500 ℃, 520 ℃, 540 ℃, 560 ℃, respectively.