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Table 2(a) Processing parameters of pulsed electron beam welding Number Accelerating voltage (kV) Beam current Peak value (mA) Welding speed (mm/s) 1 60 12 10 2 60 12 6.0 3 60 13 6.0 4 60 12 6.0 5 60 12 6.0 6 60 13 6.0 Table 2(b) Processing parameters of pulsed electron beam welding Number focusing Electric current (MA) Pulse frequency (Hz) Duty cycle 1 560 -- -- 2 560 -- -- 3 560 20 0.8 4 560 80 0.8 5 560 160 0.8 6 560 160 0.4 Test Results and Analysis Effect of Heat Input on Microstructure of Joints.
Under the condition of welding thermal cycle, the grains grow up obviously and produce thick beta columnar grains in the weld. 0 By comparing the grain sizes of Fig. 1 (a), (b), it can be seen that the grain size of the joint of No. 2 specimen is larger than that of No. 1 specimen.
By changing the duty cycle of voltage pulse, it is found that the grain size decreases.
After pulsed electron beam welding, the grain size of the weld is still growing, and the structure is growing beta grain.
The duty cycle of pulse decreases and the grain grows

However, only less than 1% of the added TiB2 particles are active for nucleation of α-Al grains [6].
Experimental Properties requirement of aluminium sheet for automotive application are met largely by a number of Al-Mg alloys (5xxx series) .
The line intercept method was used to measure the grain size along the transverse section.
Enough numbers of the potent oxide particles as nucleation substrates can enhance the heterogeneous nucleation throughout the whole melt volume, resulting in grain refinement as seen in Fig. 2.
Greer, Control of grain size in solidification, in: B.

Introduction The strength of traditional HSLA steels is contributed by a number of strengthening mechanisms, such as, solid solution strengthening, precipitation strengthening, grain size strengthening, dislocation strengthening and texture strengthening.
The distribution of high angle grain boundary is analyzed by using Photoshop and the result is shown in Fig. 8.
In the initial stage, the high angle grain boundary in bainite lath increases and a small amount of ferrite appears, making the high angle grain boundary between bainite and ferrite increase, the two factors play a leading role, the high angle grain boundary showed an increasing trend in totality.
Considering the above factors, the overall number of high angle grain boundary appears increasing after the first.
Fig. 8 Statistical result of high angle grain boundary Rolling of Steel Rolling Procedure.

It is noted that there exist elongated grain in both sintered samples.
In multi-step sintered sample, some elongated grain size is more than 10 µm, as shown in Fig. 4(a), but equi-axed grain is the main pattern in one step sintering specimens, shown in Fig. 4(b).
Which indicate that abnormality grain growth is easier to happen for multi-step sintering, the main reason perhaps is that holding at low temperature reduce the number of nucleation sites, lower the driving force for grain growth and slow the nucleation rate.
Therefore, multi-step sintering is necessary for dense Y-SiAlON grain development.
Contrast to one step sintering, multi-step sintering is favor to the Y-α-SiAlON grain development and densification and holding at low temperature can reduces the kinetics of crystal growth, which is helpful for elongated α-SiAlON development.

The detailed test plans of the resilient modulus of the selected three kinds of materials are shown in Table 3, in which, “number of test pieces = number of dry density levels × number of water content levels × number of comparative test pieces.
It is known from the analysis of data in the Table 4: (1) The ratio of fine-grained soils (FZ and NZ) on the dry side of OMC is higher than coarse-grained soils (SL), but that on the wet side is lower, which indicates that the influence of water to fine-grained soils, in relative terms, is more notable than coarse-grained soils
Tab.4 Ratio of Resilient Modulus between OMC±3% and OMC stress level OMC-3% OMC+3% fine-grained coarse-grained fine-grained coarse-grained σd(kPa) σ3(kPa) FZ NZ SL FZ NZ SL 55 60 1.53 1.49 1.36 0.48 0.40 0.85 55 45 1.58 1.49 1.37 0.45 0.38 0.85 55 30 1.61 1.50 1.39 0.39 0.35 0.84 55 15 1.66 1.50 1.42 0.35 0.32 0.83 Humidity adjustment coefficient of subgrade resilient modulus Definition of humidity adjustment coefficient.
After regression analysis, this paper respectively makes recommendation of model parameters of fine-grained soils and coarse-grained soils, as shown in Table 5.
(2) The subgrade resilient modulus of different soil types are all sensitive to the variation of water content, and the influence of water to fine-grained soils subgrade is more notable than coarse-grained soils.

It was found that the anti-oxidation effect is increased by Ce4+ modifying and with increasing layer number.
As shown in Fig. 2, the weight gain increases with the increase of temperature and decreases with the Ce 4+ addition and the increase of film number.
It can be concluded that the steel matrix is directly oxidized along the grain boundaries; and the oxidation gradually develops around the grains.
With the increase of film number, the protective effect increases.
The thicker film can effecttively retard the formation of holes and depress the oxidation around the grain boundaries.

A correlation was established between the concentrations of phosphorous and sulphur elements at grain boundaries and the presence of both creep and brittle fracture induced grain boundary facets.
Table 1 shows individual grain boundary compositions.
In total, eight measurements were carried out (illustrated by the letter A followed by a sequential number in the Table 1).
This number was a compromise between good statistics and oxidation accumulation, as stated in elsewhere [1].
For the ST+PS pre-treated specimen, a large number of inter-granular facets were observed in the high temperature failed notch and low temperature fractured unfailed notch.

The higher hardness was attributed to fine-grained microstructures in the as-rolled CSP strips.
As CSP process has a number of its own distinct features and its products have a much difference between conventional continuous casting process products.
TEM analyses of carbide precipitation show that a large number of small carbide precipitates are distributed in the tempered specimens, as illustrated in Fig. 4.
However, for the specimen produced by CSP, carbides were precipitated not only in the matrix, but also along grain boundaries and sub-grain boundaries because it has much more boundaries owing to its ultra-fine grains.
Therefore, CSP products have more fine-grained and uniform microstructures compared with conventional process [2-5].

The SEED process was employed, and the pouring temperature adjusted to prepare semi-solid slurries with different grain morphologies.
In this work, the six kinds of pouring temperatures from 630 °C to 705 °C were used to prepare slurry with different grain structures.
The entrapped air result from turbulent flow, so the number of the entrapped air can represent the flow stability of slurry.
The slurry microstructure of Tpour = 630 °C is close to globular, only at the edge region found small size dendritic grain.
The grain size increased as the pouring temperature rising, which is supported by the quantitative analysis presented in Fig. 3.

Doping leads to a further hardening due to the occurrence of Mn atoms and Zr in solid solution; grain refinement; increase heat resistance due to the establishment of the grain boundaries of inclusions of thermally stable compounds [1 – 2].
Reduced structural stability was mainly caused by particle stimulated nucleation of recrystallized grains in the deformation zones around coarse Mn-bearing phases that developed during the homogenization, and also by a reduced number density of Al3Zr dispersoids.
In the grain boundaries detected Mg2Si particles and Al6(Mn,Fe).
The number of phase L12 sample 4 more.
The number of Mg2Si particles 4 is less than the sample.