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Due to the limited number of slip systems in magnesium, elevated ECAP processing temperatures are necessary to allow plastic deformation, while on the other hand a decreasing process temperature results in a finer microstructure.
Grain size distribution shows an inhomogeneous microstructure with a mixture of coarse and fine grains.
The widest spread in grain size is found for AZ31 alloy with grain sizes from 100 μm down to 5 μm.
The finer grains form band shaped structures.
The ECAPed alloys have finer grains with average grain sizes of 4 μm, 3.2 μm and 2.3 μm for AZ31, AZ61 and AZ91, respectively.

The properties of welded joint will been improved by these fine crystal grain.
Following the increasing of magnetic field current, the number of α-Mg is increasing and display as equiaxed grain, the β-Al12 Mg17 is diffusion distribution at the grain boundary of α-Mg.
The grain consist of coars α-Mg and series β-Al12 Mg17.
These broken crystal grains can refine grain and improve the properties of welded joint.
The properties of welded joint will be improved by these fine crystal grain.

Experimental results have demonstrated that the high shear unit can be used for general melt treatment, physical grain refinement, degassing and preparation of metal matrix composites and semisolid slurries.
The polished surfaces shown in Fig. 3 show that the number of pores and their size were remarkably reduced after intensive melt shearing.
The α-Mg grains are uniformly distributed with a very narrow size range.
For the conventionally cast ingot, the microstructure consists of large dendrites within elongated grains along the solidification direction.
The morphology of the grains changes from dendritic to rather globular.

Figure 3 shows the surface roughness as a function of the number of slurry pass for various size grains.
It is found that the surface roughness decreases remarkably in the early stage of low number of slurry pass less than 40, and then the decreasing rate of roughness becomes gradually gentle as increasing number of slurry pass.
It is also found that the decreasing rate of the surface roughness for grains of 57Ǵm in size is higher than those of the other grains of 57Ǵm in size is higher than those of fine grains of 5.5 and 20Ǵm in size.
The decreasing rate of roughness in the early stage in the polishing with 57Ǵm grains is much steeper than those in the polishing with 5.5 and 20Ǵm grains.
Figures 4 and 5 show the variation of the surface roughness with the number of slurry pass for various grain concentrations and slurry injection pressure , respectively.

It has been well aware that two important strength-reducing characteristics are knots and slope of grain along the lumber.
The upper one is failed due to large knots, and the lower one is due to high slope of grain.
The SOG scanner measures the average slope of grain over the width of the lumber.
In each figure, the knot indicator and the slope of grain are plotted from the results of the 2 corresponding scanners.
It can be seen that grading with the SpeedGrader reduces the number of low-grade lumber and increases the number of high-grade lumber.

Tensile tests are conducted on a number of specimens.
There are a lot of large grains looking like cauliflower about 5-6µm which comprise many small grains about 200nm in Fig.2.
It can be seen that the average grain size on the surface of NO.2 increases significantly compared with that of NO.1, whose average grain size is about 600nm (see Fig.5).
There are many micropores at columnar grains boundaries of NO.1 (see Fig.4).
Average grain size on the surface of NO.2 is larger than that of NO.1.

In the last thirty years, a number of processing techniques have been developed to produce nc-materials.
But the average grain size of the as-prepared specimens is about 100 nm.
The average grain size of the as-prepared nc Ag did not grow much at elevated temperature.
In the annealing of nc-Cu prepared by FLM, the average grain size increased by 50% at 473K.
So the high microhardness in this study derived from ultrafine grain size (18.5 nm).

Presence of Goss grain colonies at about the quarter of the hot rolled sheet is probably, as it has already been suggested, at the origin of the Goss grain presence at the primary recrystallized state.
Many authors [2-6] have studied the influence of texture heterogeneities, grain boundary energy, grain size of Goss grains…, on the abnormal Goss grain growth from the primary recrystallized state.
These two orientations form high angles and CSL grain boundaries with the Goss grains, which favors their abnormal growth [7-13].
From these two tables it appears that the number of main orientations found by OIM® through the sheet thickness is obviously higher than that found by X-ray diffraction with which the texture is only determined at three places.
The large elongated grains are parallel to the rolling direction

The results of experiments were described on graphs of the fatigue crack length „a” versus numbers of cycles N.
The microstructure heavily dominated by elongated grains of the solid solution α of various sizes, and a width of about 50 μm.
Between large elongated grains are also visible cluster very small equiaxed α phase grains in the system band.
Precipitations phase Al2Cu occur mainly in the chain system on grain boundaries of the solid solution, and their size does not exceed 5 mm [11].
At the same time, the number of load cycles N was recorded.

This ultra-precision magnetic abrasive slurry is made by simply mixing the super-minute abrasive grains, super-minute globular iron particles, and oily grinding liquid.
The UMAS is produced by mixing simply the super-minute abrasive grains, super-minute globular iron particles, and oily grinding liquid.
The vibration frequency can be adjusted by controlling the number of revolutions of the motor through an inverter.
To the experiment of each rotation speed, finishing time was set up so that the number of rotations might become equal.
The UMAS simply mixed super-minute abrasive grains, super-minute globular iron particles, and oily grinding liquid.