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In such a set-up, the heat is extracted by a number of laminar water jets placed at regular intervals along the length of the run-out table [1].
The average grain sizes were measured to be 3.2, 2.8 and 2.5 m for ACC, UFC+ACC and UFC, respectively.
The increase in the density of high angle grain boundaries can lead to more effective strengthening by grain refinement because the presence of low mis-orientations between some grains may contribute to the reduced ky value in comparison to the ferrite grains with high mis-orientations [5].
Therefore, the better grain refinement strengthening can be achieved by UFC than by ACC.
By using UFC, the number of NbC (with the size of 5 nm) has been increased as compared to the cases of ACC and UFC+ACC, resulting in obvious refinement of precipitates.

After tempering at 650°C, the average size and number of these rectangular precipitates don't change obviously (Fig. 2b).
Determination of effective grain size measured by EBSD.
Large number of boundaries falls into the range of below 10° in misorientation angles in all these samples.
The boundaries existing in this region should be related to the boundaries between packets transformed from different {111}γ planes and the prior austenite grain boundaries. 0 10 20 30 40 50 60 0 10 20 30 40 (a) Number fraction (%) Misorientation angle (deg) 0 10 20 30 40 50 60 0 10 20 30 40 (b) Number fraction (%) Misorientation angle (deg) 0 10 20 30 40 50 60 0 10 20 30 40 (c) Number fraction (%) Misorientation angle (deg) Fig. 3 Grain boundary misorientation distribution of ULCB steels in as-rolled (a) and tempering at 650°C (b) and 700°C (c) condition.
At the tempering of 700°C the average grain size increases to 2.7µm.

The average grain size and the number of grains are 50 μm and twenty, respectively.
Comparing Fig. 4 (a) with (c), the number of grains in which the plastic strain is spreading in (a) than that in (c).
When the number of slip systems is limited, the number of grains with low Schmid factor increase compared with the case with the large number of slip systems.
Even though the number of the activated slip systems is different, plastic strains are observed in all grains, which is different from those with the high CRSS as seen in Fig. 5 (d).
Although the little amount of stress concentration is observed at the grain boundaries in Fig.5 (d) because of the large plastic anisotropy in the limited number of active slip systems, stress distribution which increases the proof stress is not seen across the grains.

With the increase of cycle number, the closed hysteresis loops become gradually obvious.
Obviously, the ratcheting strain increases sharply with the increase of cycle numbers at the initial stage, and tends to be a constant after certain cycles.
It can be seen that zone A is relatively flat, with a great number of lamellar structures.
It can be found that the twins bands are located in some larage grains , while there is no twins in very small grains.
This is atrribtuded to the critial resolved shear stress (CRSS) for twinning is not achieved in those small grains.

Additionally different second phases of varying sizes and shapes are present, including a large square-shaped Mg5(Gd,Y) particles which solidified from the melt and are located within the Mg grains and/or at grain boundaries, fine spherical zirconium-rich particles which are located in the Mg grains and fine needle-like precipitates of Mg5(Gd,Y) and Mg24(Gd,Y)5 which are uniformly distributed within the Mg grain interior.
Further, a number of deformation bands or twins were found existing in the magnesium grains.
Fig. 1b shows that a number of deformation bands or twins exist within near fully recrystallized, equiaxed α-Mg grains.
It should precipitate from the residual alloy melt at temperatures near 500 °C, as shown in Fig. 1a, and existed at grain boundaries and/or within magnesium grains near grain boundaries.
Zr-rich particles which precipitated from the alloy melt and acted as an efficient grain refiner for magnesium grains, provided locations for corrosion initiation in the Mg-Gd-Y-Zr alloy.

Introduction The behavior of solid materials put under the grinding operation is very different from a case to another, according to the great number of parameters which contribute to its performing.
A number of researchers have dealt with the study of the behavior of solid particles, belonging to different materials, under the action of concentrated forces of compression, aiming to highlight the dependence of "force-deformation".
In order to determine the final humidity of the grains, a special Granomat humidometer for cereal grains was used.
The geometry of the corn grain is presented in Fig 1.
Acknowledgement: This paper is supported by the Sectorial Operational Programme Human Resources Development (SOP HRD), financed from the European Social Fund and by the Romanian Government under the project number POSDRU/159/1.5/S/134378.

Subsequently, the grains were refined and became tiny grains under the action of a large number of edge dislocations in the crystals.
Therefore only the big grains were left after 30 minutes of irradiation. 1.
In this area, the grain size of BP is about 20-50nm.
Finally, only the large grains were left in Fig. 5 (b) after 30 minutes of irradiation.
(3) The morphology of the crystal showed that the amorphous phosphorus turned into large size BP nanocrystals under the action of mechanical milling and then, upon being refined, became tiny grains under the action of a large number of edge dislocations.

The experimental result showed that there is significant number of small precipitates within the grains besides the icosahedral quasicrystals along the grain boundaries.
A number of studies have been carried out on the microstructure, properties and mechanical process of this category of alloys, and it has been widely accepted that the creep resistance of these alloys attributes greatly to the quasicrystal I-phase (Mg3Zn6Y) in grain boundaries [7,8,9].
However, since the precipitates within the grains also contribute to the strength, it is worth to investigate these precipitates.
From this figure one can see the fish-bone-like eutectic structure at grain boundary and uniformly distributed rods within the grains.
Although the density of this kind of precipitates is not as high as the Z-Mg12ZnY and MgZn2 precipitates, there are usually more than ten of Y-riched particles in each grain.

According to the characteristic of the BSE image, B element with the smallest atomic number among Ag(47), Cu(29), Ti(22), B(2) gives off little back-scattered electron, hereby the B single is much more feeble and TiB2 particle appears darker than α phases in bright area (mainly Ag elements) and β phases in grey area (mainly Cu elements).
Many columnar compounds are formed on the surface of the brazed grains so that the grain edges are seriously destroyed, as shown in Fig.4(a).
The compounds look compact on the grain surface.
Under such circumstance, the molten filler spreads to the top of the grains so that all the grains are enwrapped by the filler layer.
The sharp edges of the grains are thus protected.

Crack length and number of cracks on the punched surface were measured and counted by an optical microscope.
Standard tensile specimens (number 5 test piece of JIS) were prepared by machining the steel sheets.
Results and discussion 3.1.Crack length and the number of cracks Fig. 6 Relationship between the number of cracks and crack length.
Moreover, Mn segregates at the grain boundary, and Mn weakens grain boundary cohesion.
Moreover, Mn segregates at the grain boundary, and Mn weakens grain boundary cohesion.