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The BSE signal is stronger from the elements with a higher atomic number (atomic numbers: Mn - 25, Ni - 28, Ga - 31).
On the wheel side of the ribbon, the structure of equiaxed grains is present, together with some grains elongated in a direction transversal to the rotation of the wheel (Fig. 8 (a)).
The linear grain size is 1.5. µm.
The linear grain size on the free surface of the ribbon is 6 µm.
These grains have random crystal orientation (Fig. 7 (a) and (b)).

This method offers the possibility of obtaining a thin, uniform nanometric layer of Ni-P particles on the surface of each grain of the ceramic powder and consequently an Al2O3/Ni-P nanocomposite with a uniform percolated structure.
The dark areas of Ni-P (attracting the magnetized tip of the microscope), surrounding non-magnetic ceramic grains can be clearly seen Fig.1.
HRTM images of: a) interfacial bond between Al2O3 and Ni-P, b) interface between grains of Al2O3 The results of hardness measurements of the composite samples, shown in Fig.5, showed significant changes.
In principle, the combination of Al2O3 and Ni-P with different sized grains and a structure with uniform percolation offers attractive physical and the mechanical properties and is currently the subject of further research.
Acknowledgment This research has been financially supported by the Polish State Committee for Scientific Research under contract number 4T08D03225.

It was found that the packet size increased with the prior austenite grain size but the increment was small.
Then the system of the two steels is forged to produce a high number of layers by successive forge/fold operations.
Number of small packets is found plentiful in the analysed areas.
Formation of prior austenite grain and packet were not much distinctive but the blocks within the packets were fairly observed.
It was found that the packet size increases with the prior austenite grain size but the increment is small.

A fine-grained material is harder and stronger than that with coarse grains because it has a greater total grain boundary area to impede dislocation motion [3].
But it can be seen that the grain size distribution tends to be rather heterogeneous: grain sizes vary from 3 to 30um with an average of 13um.
The number of independent modes for the basal is only two, which is not sufficient for satisfying the von Mises criterion [5].
Fig.2(a) shows inhomogeneous grain size distribution, the fraction of small grains was much larger than that of the extruded one, and average grain size was also much smaller than the extruded alloy.
Simultaneously, when rolling at 673K, the grain size became larger, and the growth of DRX grains was determined as shown in Fig.2(c).

Obviously the matrix was composed of transformed β grains with small size, the grain boundary was relatively clear, most of the equiaxed α phase grew up along the grain boundaries.
The size of transformed β grains increased but the size of equiaxed α phase hardly changed in Fig.2b.
Firstly count the number of grain of αp and αs in the field of known area A, calculate the average area of the single grain of αp and αs with Eq. (1),have the radius r to the equivalent circle of the single grain αp and αs with Eq.2, finally guide the data into the origin 8, and generated the radius trend of four samples.
All of this owed to the following reason: a comparatively short period of heat preservation made primary α grain size not in average size, and bent grain boundary moved to the curvature center by surface tension, ending up with growing of big grain and decrease of small grain.
As heat preservation prolonged, grain will be distributed uniformly in the alloy, grain surface tension will decrease, making a stable state for grain, and the influence of dynamic factors will also decrease gradually.

Whereas discontinuous precipitates nucleate on the boundaries of the solid solution grains and when growing, they take the form resembling nodules [6].
After die-casting, the structure of Mg-Al alloy is characterized by significant grain refining of α-Mg solid solution, however Mg17Al12 phase, together with α-Mg solid solution, forms fully divorced eutectic on the grain boundaries of α-Mg solid solution (Fig.3).
Coalesced precipitates of Mg17 Al12 phase on grain boundaries in Mg-5Al alloy, after annealing at 180°C/500h/air.
Process is started on the grain boundaries of α-Mg solid solution and consist in cellular growth of plate precipitation of Mg17Al12 phase in the direction of central part of the grain.
The Mg-5Al alloy after die-casting, is characterized by significant grain refining of α-Mg solid solution with fully divorced eutectic on the grain boundaries of α-Mg solid solution. 3.

PEENED SURFACE BULK MATERIAL'S HARDNESS Depth Depth Hardness MICROHARDNESS VARIATION Compressive residual stress (roughened) Microstructural distortion INTENSITY (velocity) INCIDENCE ANGLE Fig. 1 Schematic illustration of the peening parameters-induced surface modifications originated by the shot peening process. σ1 Grain Boundary Crack Plastic zone σ2 σ3 Grain σ1 Grain Boundary Crack Plastic zone σ2 σ3=σc3 Grain σ1 Crack Plastic zone σ2 σ3 Grain Grain Boundary a) b) c) Conditions for crack arrest are met when the stress concentration at the grain boundary does not reach the level required to initiate a new slip band across the grain boundary before the crack tip reaches the grain boundary [9], as shown in Fig. 3.
σ1 Grain Boundary Crack σ3 Grain σc3≤ In this work, the NR model is used to model the conditions for crack propagation or crack arrest.
Fig. 3 Schematic representation of crack arrest.The stress bounding condition for fatigue crack propagation and crack arrest area is expressed as [9, 10]: i FL 1 arrest 1 1 m σ -σ 2a σ = + σ , i = m D i . (1) where, σFL is the fatigue limit of the material, a is the crack length and D is the grain diameter, i is the number of half grains covered by the crack and thus the non-dimensional crack length, i = a/(D/2).
The ratio mi/m1 is the grain orientation factor of the ith grain, which is given as [12]: ( ) i i 1 m = 1 + 0.5ln i for 1 m 3.07 m ≤ ≤ . (2) The grain orientation factor m1 is related to the first grain and mi is the average factor corresponding to other successive grains.
This diagram shows, for a number of metals, that there is a dividing line, considered to be the bounding condition between propagation leading to failure and non-propagating cracks or crack arrest.

In china, such as Huabei oilfield, Changqing oilfield and Jilin oilfield, in which there were a large amount CO2 flooding, a number of oil wells are discarded caused because of CO2 corrosion [3-6].
This may be because of FeCO3 crystalline grain deformation at high pressure.
The biggest difference of surface crystalline grains under critical pressure is that the grains become small and compact.
Such deposition occurs on the existing grain surface and grain interspace, which can make the film more dense and eventually cause the film layer to be passivated.
This is consistent with the change of crystalline grain size and film thickness.

Although during billets drawing in this tool a fine-grained structure and the necessary level of mechanical properties of forgings for a smaller number of passes is ensured, there is a larger change in the billet initial dimensions compared to the step dies.
Billets with the same sizes were deformed in the old designed step-wedge dies and step dies with the same number of passes as during deformation in the newly designed step-wedge dies.
To determine metal grain size deformed by the proposed and current technologies GOST 5639-82 "Methods for detection and determination of grain size" was used.
Optical microscope OLIMPUS BX53M was used to determine grain size.
Ghosh, Production of ultrafine-grain microstructure in Mg alloy by alternate biaxial reverse corrugation, Acta Materialia, 54 (2006) 5147–5158

While the grain orientation in bulk samples was random the grains in the thick films were aligned along the substrate plane.
BLSF have the general formula (Bi2O2) 2+ (Am-1BmO3m+1) 2, m is the number of BO6 octahedral layers in the perovskite slab.
The observed grain growth rate in thick films was much higher than in bulk ceramics.
The grain orientation was more pronounced in the films sintered at higher temperatures.
Thicker films had smaller degree of grain orientation than thinner films.