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The lamellar grains of Ti3SiC2 have the dimension of 16 µm in length and 4 µm in thickness for the fine-grain (FG) sample, and 50 µm in length and 15 µm in thickness for the coarse-grain (CG) sample.
SEM image and XRD pattern of fine-grain(FG) Ti3SiC2 (a and b), coarse-grain(CG) Ti3SiC2 (c and d), fine-grain(FG) Ti3AlC2 (e and f), and coarse-grain(FG) Ti3AlC2 (g and h).
Total number of cycles was 19 at 900 o C, 18 at 1050 o C, and 19 at 1200 o C during the period of 40 hr.
Barsoum et al. [2] previously explained that the effect of grain size was quite subtle, and the coarse-grain (CG) sample oxidized slightly slower than the fine-grain (FG) sample, owing to the anisotropy of oxidation.
It seems that, instead of the grain size, the anisotropy of matrix grains and the amount of retained TiCx affect the oxidation resistance much.

These, however, are costly, time consuming and results are not always easy to analyze given the number of variables involved.
All numbers are given in % weight except for N given in ppm.
Variation of temperature versus pass number for the production of wire rod.
Estimated austenite grain size during rolling.
Comparison between measured and predicted ferrite grain sizes.

The minimum ferrite grain size obtained by the new TMCP is less than 1µm.
Vickers hardness and tensile strength increased with increasing number of process.
Fig.5 shows the relationship between Vickers hardness and number of passes of side extrusion.
Hardness increases with increasing number of passes of shear deformation.
Tensile strength increases with increasing number of passes of side extrusion.

A highly heterogeneous sample, containing grains, grain boundaries and weak zones, is employed in the numerical simulation.
A large number of computer codes for flow-stress or flow-strain coupling analysis have been developed in recent years [3, 4, 5].
The numerical modeling is conducted on a numerically rectangle sample that is assumed to be composed of rock aggregate, grains, grain boundaries, weak zones and water.
the boundary of the grains and weak zones.
It can be seen that the onset of failure in the specimen is first indicated by the formation of a large number of isolated fractures (Fig. 5 [a]).

Mechanical tests such as compression parallel and perpendicular to grains, tensile strength parallel to grain and bending strength test were all carried out.
The direction of shearing was parallel to the longitudinal direction of the grain.
The result of each test was recorded while the Brinell hardness number was obtained from Equation 15.
The arrangement of the grains, the bonds within the grains and the pore sizes contributed to the structural characteristics and failure patterns of each timber sample.
Birchwood very tiny pores EDX Analysis The EDX analysis showed the peak position, frequency and the number of atomic elements present in the wood samples (Figs. 18-20).

Table 2 shows the mean grain size of the experimental alloys with different Ti content.
Fig. 1 Microstructures of sand-cast alloys (the numbers are coincident with those in Table 1) Fig. 2 SEM morphologies of β phase of alloys (the numbers are coincident with those in Table 1) The distribution of Ti in β phase and matrix of sample 3 was determined by EDS analysis.
Part of Ti is also gather- ing along the grain boundaries.
This may be the reason for the grain coarsening of primary phase.
The grain coarsening is the dominant factor for the alloy.

It is noticed that the microstructure is equiaxial recrystallized structure with average grain size of 6.5µm, and some small grains are found to surround some large ones.
When the temperature is increased to 200℃, the microstructure after deformation is characterized by recrystallized equiaxial grains with an average grain size of about 3.7µm (Fig. 5b).
Although the grains are slightly elongated along the tensile direction, the morphology of the grains is still equiaxed, indicating that the growth and movement of the grain are isotropic during superplastic deformation, and GBS is the main mechanism of the AZ31 alloy for superplastic deformation.
As the temperature rises to 200℃ (Fig. 6b), a number of equaxial dimples appear on the fracture surface, showing typical dimple-aggregating fracture.
This can be attributed to a large number of dislocation motion and dislocation pile-up, and then resulting in the occurrence of a number of cavities.

Results Grains will grow up gradually and be well spheroidized during the resting process after stirring, but long time resting may make the grains coarsening.
Concave parts of the grains were filled up due to atom diffusion.
The reason is tiny grains with low melting point melted and disappeared, and large grains survived and grew.
Fig. 3 Micrographs of semi-solid slurry with different resting time (a) 0s (b) 30s (c) 60s (d) 90 s Discussion Large numbers of well-ordered clusters will be formed in the melt because of structure and energy fluctuation existing in molten metal.
At last, spherical grains were formed.

Where, is the average particle diameter. is the total area of particles, and is the total number of particles.
As shown in Fig.2(c), while the pouring temperature is 600℃, rosette non-dentritic grains are rounded up to uniformly distributed grained and spherical grains with the average diameter of 49.9μm and shape coefficient of 0.71.
Therefore increase of nucleation and refining of the grains were intensified.
The most sensitive areas such as dendrite arms of dendritic particles were broken and a number of fine grain formed[15].
(2)Vibration can refine the grains of the ZAlSi9Mg alloy.

Due to the abrasive grain of the #4000 wheel is the smallest, the #325 wheel is the biggest (The grain size is shown in Table.2.), grinding wheels with different size grains show different effectiveness in grinding process.
In the case of the #4000 wheel, the ratio between the size of abrasive grain and the thickness of the oxide layer is so large that the abrasive grain are all covered by the oxide layer (as shown in Fig.9(a)) [5].
Table 2 Grain sizes of the wheels Grinding wheel #325 #2000 #4000 Average grain size[µm] 60 6.8 4 (a) Wheel with smaller abrasive grain size (b) Wheel with bigger abrasive grain size Fig. 9 Grinding process diagram of wheels with different abrasive grain size Summary Some cast-iron bonded diamond grinding wheels with ELID were successfully applied for efficient and precision grinding of tungsten carbide.
(2) The abrasive grain size smaller, wore sooner, but the ground surface better.
Volume 13(2006), Number 4, PP 363-367