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In the as-supplied state the 12Cr1MoV steel has ferrite-pearlite structure with a characteristic grain size of 30 ÷ 50 µm.
It is found that the specimen without the surface treatment has the pronounced grain-patterened strain induced relief.
The graphs of dependence of the main crack length versus the number of cycles were plotted.
The number of cycles before the crack nucleation is increased approximately by 2 times.
Cyclic tension tests of 30CrMnSiNi2 During the tests the average number of cycles prior the fracture were determined.

Short diffusion paths caused by the increase of dislocation density are not sufficient for the same mass-transfer in the volume of a crystal as the transfer on the boundaries of grains and sub-grains.
Therefore, in all the cases when elastic and plastic stressing exceeds several dozens of minutes or the energy, introduced to the crystal is little, penetrative atoms localize on the boundaries of grains, sub-grains and phases.
The height of micro-irregularities in the middle of grains did not exceed ~0.05 micrometers.
This is proven by decrease of ion flow passing through GB and decrease of a number of recovered silver micro-crystals at GB auto-radiograph.
Under these conditions the diffusion is characterized by presence of a concentration maximum and its shift at each act of deformation, by volume distribution pattern, and by impoverishment of the areas along the boundaries of grains and sub-grains.

A number of experiments and calculations have shown that dislocation motion occurs in response to sintering stresses.
Rapid grain growth is noticed once the grain boundary breaks away from the pores (Fig. 6).
This was a federation of trade associations ( presently 6 in number) , all concerned with some aspects of powder metallurgy.
The volume number of 2015 issues is 62.
APMA is for the time being under the broad umbrella of JPMA, till its members ‘ number reaches a significant value.

Microscopic examination revealed that the morphologies consisting of grain boundary growth, scattered laths and bulk form of martensite were obtained.
Therefore, an easy direction of austenite growth must be parallel to the grain boundaries.
The numbers “0”, “1”, “2” and “3” with each heat treatment cycle respectively represents the un-tempered and one, two and three hours of tempering.
The AC with grain boundary growth morphology of martensite showed improved tensile properties with three hours of tempering.
The grain boundary growth morphology of martensite in AC showed a mild decrease in strength with minimum gain of ductility.

According to Scherrer equation and on the basis of XRD spectrum, the grain length can be calculated.
Either circumstance will lead to the increase of the average grain size of the powders.
This means that under that condition, the largest numbers of Gd3+ moved into the ceria lattice of CeO2.
The average grain size changed from 45.9 nm to 61.5 nm, because the increase of temperature boosts the activation energy needed for grain growth and thus facilitates its growth.
The number of pores declines and the relative density is relatively high.

Researchers have explored a number of techniques to remove quenching residual stresses for minimizing distortions in the machined components.
However, it may involve a number of variables, and each technique has certain limitations.
It is typically forged grain structure of equiaxed morphology (Fig. 4a).
The elongated grains of stock material (extruded grain structure) were transformed into compact grain structure.
The microstructure analysis showed that fine grains of 50-800 mm were present in the center of the disc, whereas 1-3 mm large grains in the outer peripheries (Fig. 5).

In the optical microstructure and SEM very fine equiaxed grains are formed in the stir zone.
No significant grain coarsening in the HAZ was observed [3].
The grains in the advancing side of the TMAZ region bend forward in the working position whereas in the retreating side Fig.7, they bend in the reverse manner, smaller grains can be seen in TMAZ zone since much more heat generation than in HAZ.
The TMAZ, showed severely deformed, uncrystallized grains [4].
The maximum hardness value were attained for the specimen number 7, 8, 3 when using T3 and T4 tool profile with 135 HV and minimum hardness value attained 75 HV for the specimen 6.

However, the polycrystal is composed of many grains with disordered orientations.
The finer the grains, the wider the diffraction peak will be[3].
While at the same heating rate, the temperature of the endothermic peak becomes lower with a longer milling time, indicating that during ball milling, reaction takes place between the reactive particles (for example, fine grains and grains with many defects).
L[5] pointed out that the large number of defects caused by mechanical alloying can lower the activation energy, thus promoted the diffusion course of mechanical alloying process.
The boundaries among grains are not clear.

The Microstructure of pre-creep tested samples of alloy NZ2 shows that the Laves precipitates Zr(Fe,Cr)2 is evenly distributed in α-Zr grains and on grain boundary with the size not less than 0.2µm, the result is largely same as the previous work by authors [3] .
Samples of Zircaloy-4 have similar microstructure to NZ2 except with less precipitates number density as total amount of Fe and Cr is less than NZ2, but the main feature is largely the same as reported by many researcher worldwide.
The precipitate spins dislocation and grain boundary.
The creep fracture exits many dimples, their size is largely corresponding to the size of α-grain or of large precipitate, it indicates the fracture happens in grain boundary of α-grain or boundary of large precipitate, the boundary of large precipitate along with grain boundary is failure path.
The creep is controlled by dislocation glide-climb mechanism during creep process in stress level of 117 MPa, 139MPa, 157MPa at 400 °C, the dissovle and growth of precipitate is diffusion controlled caused by channel effect of dislocation, creep fracture happens along grain boundary or large precipitates boundary.

However, the high levels of precipitation strengthening resulted in deteriorated toughness and unacceptable variability in mechanical properties since Ti is only a moderate grain refiner [3].
The average ferrite grain size was 4.4±0.2µm (Fig. 1a).
The TEM study also showed the presence of two types of ferrite grains (Fig. 1b): (i) recrystallised grains with the size of 1.4±0.2µm, low dislocation density and high angle of boundary misorientations (Fig. 1b); and (ii) elongated grains with high dislocation density and size of 1.9±0.1µm in thickness and 2.7±0.1µm in length.
The volume fraction of recrystallised grains was 34±8 %.
The largest number of particles had an average size of 25±5nm with average distance between precipitates of 300±50nm.