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Heterogeneous microstructure of Ti3SiC2 in this study consists of elongated and equiaxed grain.
The elongated grain was typically ~50 µm long and ~15 µm wide, while the average size of equiaxed grain was ~5 µm.
Cracks were always found to decelerate first and to be arrested finally with the number of cycles.
No obvious bands of grain dislodgment are observed even at 10 6 cycles.
The damage developed with the number of cycles, indicating a mechanical effect.

For a number of materials used in modern engineering, the maximum possible decrease of the temperature-time processes parameters of the deposition of protective coatings can only be achieved (according to results [1-4]) by using species-activators evolving hydrogen fluoride (HF) during the chemical-thermal treatment.
Techniques and Physics of Creating Liquid-like Structures at Grain Boundary Regions One can use original results [13-15] on the techniques, physics and technological possibilities of creating a liquid-like state in the grain boundary nanoregions in metals and alloys.
It can be also noted that the adequate Arrhenius-type treatment (data in [23] and similar ones) should be carried out for moving grain boundaries with a close degree of faceting.
Particularly, the data [16-21] on "the solid state wetting" of the intergranular regions in Zn-Al alloys, the liquid-metal deep etching of the grain boundary regions in metallic systems (i.e.
"Motion of the faceted 57° [1120] tilt grain boundaries in zinc". // J Mater Sci Vol. 43 (2008), p. 3860-3866

Characterization by means of optical and scanning electron microscopy, transmission electron microscopy and X-ray diffraction has shown that the microstructure of the investigated steel contained a ferrite matrix with fine grain size, bainite with small bainitic packets, and high volume fraction of retained austenite with a large number of granular retained austenite.
The average ferrite grain size was measured as 2.85μm.
According to Hall-Petch equation a decrease in the grain size generally leads to an increase in the ultimate tensile strength and the yield strength The grain size of ferrite in the tested steels is about 3μm, which is beneficial to the increase of the strength of steels.
However, the strength of the TRIP-aided steel is not only a function of the grain size.
The grain size of ferrite does contribute to the strength, but there are other factors affecting the strength, as ferrite is only one component of the multiphase microstructure.

A continual grain refinement from the initial grain size of 250 µm down to a sub micron range was observed with increasing number of passes under both routes.
Tensile stress-strain curves for the material that was pre-strained by various numbers of ECAP passes (Route C) are shown in Fig. 3.
Tensile deformation curves for IF steel at room temperature after pre-straining by different numbers of ECAP passes (Route C) [6].
Relatively large grains (average size about 20µm) are embedded in a much finer grain structure [5].
Ultrafine Grained Materials III, Y.T.

To get an idea of the initial grain structure of the slabs, the calculating method on the cross-sections of the unequal grains boundaries, described in GOST 5639-82 "Steels and alloys, was used.
Methods for detecting and determining the grain size".
The method consists in counting the grains intersected by segments L=1 mm on the grinds made along and across the main axis of symmetry and determining the number of grains in 1 mm3.
The average number of unequal grains in 1 mm3 of the volume of the slot was calculated by the formula (1): Nv = 0.7*Nx*Ny*Nz, (1) where 0.7 is the coefficient that takes into account the grain unevenness; Nx, y, z is the number of grain boundary crossings per 1 mm in three different directions.
Changing the grain size when analyzing in planes parallel to wide faces A) B) Fig. 7.

Compared with the as cast alloys, precipitates segregation is reduced along the grain boundaries, and the grain boundary is very clear, smooth and uniform distribution.
In Fig 3 (b), diffraction peaks of Mg matrix are decreased while the number of precipitations containing rare earth are increased.
At ambient temperature, the tensile fracture of a large number of alloy exists larger cleavage plane, it is visible clearly.
At 250℃, the fracture has a large number of torn edges, and cleavage plane disappeared, ductile fracture characterization increases.
The micro-cracks can be developed into the hole-shaped grain boundary and grain boundary intracrystalline cracks, and also can be extended to the grain boundary.

The differences arising on cavitation erosion resistance are explained through modifications of the crystalline grains dimensions, the chromium carbides proportion and some intermetallic phases not dissolved in austenite and of resistance to plastic deformation 1.Introduction The austenitic stainless steels are widely used in liquid handling systems and hydraulic machines due to excellent corrosion resistance, good processability and a reasonable cost price [1], [2] [4], [5].
At the same time, grain size is influenced by the level of the mechanical properties, mainly of the hardness, tensile strength and yield strength limit [1], [2], 5].
By the melting welding of these steels, heat affected zone is the seat of some important variations of temperature from the adjacent portion of the welding cord to the base metal, which influence the degree of chemical and structural homogeneity of austenite and wavy grain.Therefore, the present work aims at highlighting the influence of solution treatment temperature to erosion through cavitation behaviour of stainless steels with the predominantly austenitic microstructure. 2.
Fig.1 Heat treatment Once the increasing heating temperature is intensifies the phenomena of diffusion of carbon and alloying elements in the array of austenite by increasing degree of chemical homogeneity of its and dimensions of crystalline grains.
Irrespective of the value of the temperature of austenization, the cavitational attack is triggered on crystalline grain limits and on the strips of slip, and loss of material occurs by being ductile breaking.

The abrasive grain is attached to a grain-fixture by using glass solder or galvanic bonding.
He established a formula (2) based on the specific cutting force k (see formula (1)), the chip cross section Acu, the number of kinematic cutting edges Nkin and a material constant n.
Afterwards, the simulation evaluates the topography in discrete sections perpendicular to the cutting speed vcy and calculates the area Acu and number of grains Nkin which are in contact with the gear.
The values for the simulation with grains fluctuate around the values without using grains.
Currently, only a limited number of models for the calculation of cutting forces exists [13].

Typical microstructure of steels processed in this manner consists of quasi-polyhedral austenite grains embedded in a ledeburite-carbide network.
Since austenite is a metastable component depending on oversaturation with a number of elements, its thermal and mechanical stability needs to be known.
Initial microstructure of experimental material The material upon mini-thixoforming contains polyhedral austenite grains in carbide-austenite network.
The mean size of austenite grains, 12 – 14 µm, is considerably smaller than that of conventionally thixoformed materials.
In order to allow selective testing of mechanical properties of austenite without effects of the ledeburite network, a suitable region within a polyhedral austenite grain was identified using a scanning electron microscope.

When Δ=1.0, the grain will directly generate cellular dendrite and it does’t appear segregation phenomenon.
is 6 in this paper;θ is angle between the dendrite spindle direction and the normal to the interface; An is the perturbation factor;β is a normal number;rn is a random number sequence, which is in the interval [-1,1] uniformly distributed; μ0 is a normal number.
This indicates that over degree of undercooling favors dendrites growth; when undercooling increases to some value, due to the huge driving force of grain growth, the grain will directly generate cellular dendrite as seen in Fig. 2 (f).
But with the undercooling increasing, the segregation phenomenon decrease slowly; When Δ=1.0, due to the huge driving force of grain growth, the grain will directly generate cellular dendrite and it does’t appear segregation phenomenon Acknowledgments This work is supported by the Science Foundation of East China Jiaotong University (No. 11JD03), Science Foundation of Jiangxi Province Education Department (No.
Simulation of Recrystallization Grain Growth during Re-aging Process in the Cu-N-Si Alloy Based on Phase Field Model, J.