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Introduction Grain refinement is one of the three major technology means of new type alloy, which internationally make traditional material upgrade and create [1] .
The small grain can improve the toughness of the material.
Through its analysis of process parameters, seeking some of the methods and points to improve the preparation of excellent refinement capabilities Al-Ti-B grain refiner, to obtain the desired process parameters.
Time 40min Analyzed in Figure 4 ,Figure 5, Figure 6 and Figure 7, the reaction time was 10min, A striking lack of reaction time, the size and the number of the generated TiAl3 is small; As the extension of reaction time, the size and the number of the generated TiAl3 becomes large, when the reaction time is 40min , TiAl3 assembled partly .
Superheat temperature reached 9300C, the morphology of TiAl3 phases had mutations, a large number of elongated needle appeared.

The route B and C sample exhibited near-equiaxed grains of ~0.5 µm in size (Fig. 1-b and c).
The grains in the route A, B, and C samples were very fine and of a similar size.
This indicated a change in grain boundary characteristics from low-angle to high-angle grain boundaries with increasing ECAP severity.
Interestingly, the route B and C samples showed relatively equiaxed grains with irregular orientations.
Although the number of voids decreased with increasing distance from the fracture surface, they were still observed down into the interior distant from the fracture surface.

The results show that at 1300℃ a large number of CAS2-Al2O3 caking formed the basic skeleton and some particles were not condensed.
At the same time, little Al2O3 grains are precipitated.
When the holding time extends to 1h, a large number of particles are formed and bonded, the sample porosity reduced and the density increased.
For 4h, the crystal boundaries intersect with each other, the caking body is evener, and a large number of Al2O3 is precipitated.
When the rate reaches 4℃/min, crystal grains are even and clear; grain interaction bond is close, but the blowhole rate increases.

Their experimental results showed an increase in alignment of SiC particles in the direction of extrusion, reduction in number of SiC particulate clusters, and improved distribution of the SiC particles as the extrusion temperature decreased.
Average grain sizes of 10-20 μm were achieved by this two-step process.
Grain size refinement.
Fig.8 Grain size of billet and extruded tube Tensile test.
A grain size of less than 10 μm for the extruded products with extrusion temperature of 300℃ was obtained, which is much smaller than 84 μm for the grain size of the billets.

It is a material based on a fine-grained cement-based matrix, fiber reinforced, fabric of acrylic-resistant glass, basalt or carbon reinforcement.
The concrete had a fine-grained matrix according to a recipe designed at the Klokner Institute.
The material properties of the matrix and of the glass reinforcements were determined by a number of accompanying tests.
Load displacement diagram: Three thin-walled elements - plates (Tab. 1) made from fine-grained concrete - were subjected to a four-point bending loading test (Fig. 1).
There is also a significant shift of bands around 1000 cm-1 range towards lower wavelength numbers.

Lifetime was defined by number of power cycles needed to cause open circuit.
The selectively occurring damage is attributable to variations in dislocation activity from grain to grain due to effects of crystal orientation and grain size.
EBSD showed that grains that preferentially grew could be traced back to certain grains in the original microstructure, suggesting that recrystallization did not take place.
EBSD maps show changes in grain size and orientation.
The process was consistent with variations in dislocation activity from grain to grain.

Fig. 2a shows the S-N curves of applied stress amplitude versus number of cycles.
These fine grains are much smaller than the original grains (Fig. 1a).
Near this fine grain area, high density of low angle grain boundaries (white lines in Fig. 4b) have formed.
The size of “fine grains” depends on the stress concentration in the area and number of cycles.
Plastic deformation in the “fine grain, (b).

The average grain size (d) was determined by lineal intercept method [19], given by d = 1.56L/MN, where L is the random line length on the micrograph, M is the magnification of the micrograph, and N is the number of the grain boundaries intercepted by lines.
TiO2 is commonly used as the grain growth enhancer to achieve large grain growth [22, 23].
For low-voltage varistors, grain growth is desired to reduce the number of grain boundaries across the terminals of the varistor device.
Less number of grain boundaries will reduce the number of potential barriers and give rise to lower voltage across the terminals thus qualifying the varistors as a low-voltage model.
Grain junction properties of ZnO varistors, Appl.

In many applications, such as milling or percussion drilling, they are subjected to fatigue with considerable loading cycle numbers.
Thus S-N curves (so called Wöhler plots) are determined to limited number of loading cycles < N= 107.
The data indicate a continuous decrease of fatigue life without any horizontal section even up to 1010 number of loading cycles.
Fig.5: Normalized S-N curves of hardmetals with 10% Co content and grain sizes of 2µm and 0,4µm Fig. 6 shows as an example the pronounced influence of residual stresses on fatigue life which decrease with increasing number of loading cycles, possibly due to changes in fracture morphology.
Both curves are steadily decreasing, and pronounced difference was observed between the stress amplitudes of the two curves at 107 numbers of cycles.

CA cell size [μm] Number of crystallographic orientations 50 52 Volume nucleation Surface nucleation ∆TN [°C] ∆Tσ [°C] nmax [m-3] ∆TN [°C] ∆Tσ [°C] nmax [m-2] 5.0 1.0 3.0*108 1.0 0.1 5.2*106 Results and Discussion In order to obtain better quality castings, the continuous casting process parameters must be adequately controlled.
Quantitative comparison of grain size for various casting speeds.
As the pouring temperature increases, the grain size of the middle columnar grain gradually becomes bigger, staying in the range of 300 to 600 µm.
The zinc content thus affects the grain size.
The same trend is shown by a quantitative comparison of grain size, as shown in Fig. 12; the grain size is in the range of 100 to 200 µm.