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Large numbers of studies have found that the structural steel contains trace amounts of boron can significantly improve its hardenability and improve the fracture toughness of the steel in the smelting process.
Adding trace boron into heat-resistant steel and alloy can strengthen the grain boundaries and improve the hot strength [4].
But after added the Boron, the edge of the lath sample martensite appeared the special carbide pearlite lamellae organization (F+Cr23C6) [8], and this lameller organization which majority around the grain boundary made the grain boundary surrounding produce lean chrome area, thus facilitated boron-containing sample tendency to intergranular corrosion in chloride solution.

Large numbers of examined results indicated that the trend of banded structure decreased, banded ferrite changed discontinuity, grain appeared equiaxed and slightly coarse.
Carbide spheroidizing, surface decarburization and grain growth appear during the process.
The steel tube is only relief annealed when it is heated below 710℃ heat preservation long time when lining glass resulting to the carbide spheroidization and grain growing gently.

(3) Thus the grinding force in perpendicular to the direction of the polar diameter OA is as follows： (4) Where: ; = The grinding force per area; =the radius of the curvature circle; =the depth of cut; B=the width of Cam; = half Apex Angle of grains; N=the number of grinding grains; The mathematical model of C axis grinding force is: (5) Where: The analysis of the Grinding wheel-X axis grinding force.
The radius of Cam basis circle is 17.5 mm; the grinding wheel radius is 500 mm; the grinding force per area is 8N [14]; the apex angle of grinding wheel grinding grain is 120o; Insertingandinto Eq. (9) and obtaining the result curve as shown in Fig. 4.

This peak is generally attributed to the transverse optical mode (TO) of crystalline silicon and is shifted to smaller wave numbers for decreasing crystal diameter due to the spatial confinement of phonons.
Therefore, it is reasonable to suppose that the oxygen is active ionizing the erbium, while hydrogen is essential for the passivation of crystallite grain boundaries and dangling bonds in the amorphous matrix where crystallites are embedded in.
Similarly, the main role of the large hydrogen content in the first group of samples consists in the saturation of the DB in the amorphous matrix and on the crystallites grain boundaries.
For the group of samples with a large crystalline fraction and larger crystallites, oxygen also participates in the grain boundaries passivation, forming SiO bonds.

The larger dielectric constant of the films annealed at a higher temperature should be attributed to the increase in grain size or improved crystallinity of the thin film.
As shown by the XRD patterns, as the annealing temperature increased from 700°C to 800°C, the crystallinity improved which was possibly accompanied by grain growth.
The improvement in crystallinity and grain size in turn increases the dipole density, which is responsible for the increased dielectric constant [11].
It was reported that in the sol-gel method of preparation, as the number of layers increases, the porosity in the film decreases because subsequent layers coated on the first pyrolysed layer will cover up the pores and the bulk defects left behind by the burn-off of organic materials [12].

Microstructural study The FESEM micrograph of the sample on Fig. 3 showed carbide precipitation in grain boundaries that indicated the formation of continuous films (including 15.71% Cr) and dispersed particles (include 4.31% Ti) of carbides, respectively.
Furthermore, there were also a large number of cracks at different regions of the blade because of the operations at high temperatures and stresses over a long period of time.
The crack initiation was probably due to a thermal fatigue mechanism, as a result of high thermal transient loads and crack grain boundary initiation and propagation in the intergranular region [8, 13].
Metallurgical analysis showed formation of cracks, fractures and coarsening of grain boundaries on the material due to high stress and temperature condition.

It is well known that MA processing leads to a continuous decrease in grain size and to an increase of the number of structural defects, local stresses and grain boundaries [9].
In spite of the decrease in grain size reported above, the raw materials do not react to form the apatite-like phase.

., packets (the region sharing nearly the same trace direction on polished surface) and blocks (the region observed as a single grain by optical microscopy (OM) or scanning electron microscopy (SEM)).
In martensite (Fig. 2(a)), a prior g grain is divided by several packets, each of which exhibits nearly the same trace direction on the polished surface.
A number of low angle boundaries in each Bain region are seen the sub-block boundaries.
The boundaries between different Bain variants are most important as well as prior austenite grain boundaries for fracture of lath martensite and baintie.

Mechanical alloying is one of the methods of producing homogeneous, fine-grained alloys in the solid state; thus providing a processing technique that can avoid the large-grained inhomogeneous structures resulting from conventional casting processes [5,6].
The Williamson–Hall method [12] was used to evaluate the grain size and microstrain using XRD data.
For every measurement, six indentations were made and the average value of 6 was reported as hardness number. 3.

The privileged location of corrosion of these alloys are grain boundaries [4].
The highest number of pits were observed for alloy with the addition of the titanium, the lowest for the base alloy and with the addition of rare earth elements.
The limiting factor of increase of corrosion resistance is influence of addition of REE on the on the grain refinement.
The grain boundaries are privileged (active) location of corrosion.