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The thickness of the annual rings and the slope of grain were also measured.
The tension force (samples were loaded parallel to the grain) was increased gradually.
The sample failures were caused by reaching the critical tensile stress perpendicular to the grain.
The screws were oriented perpendicular to the grain.
However, as the number of samples is small, the presented results are prone to a statistical error.

As can be seen, the process of matrix sintering had finished, but the boundary of solid grains is clear, the pores are still a great many and the pore shape is not regular, the matrix is less homogeneous and compact.
In alternating magnetic field, the powder induced electromotive force and breakdown the oxide between the powder particles, that the matrix inside will produce many eddy current The interaction of the eddy current in matrix with the external magnetic field arose the mechanical microscopic vibration of crystal grains in matrix[5].
As it can be seen from Table 2, the average impact energy of different numbers corresponding untreated specimens caking of group A is 6.616; and group B specimens processed by the magnetic impact energy were averaged 8.983.
The mechanism of abnormal grain growth in polycrystalline diamond during high pressure-high temperature sintering[J].
Grain boundary engineering by magnetic field application[J].

The narrow very fine grain at theperipheral zone is connected to a coarse lamina structure extending to the core with large columnar grain fraction.
The fine grain at the peripheral zone is formed due the fast extraction of heat through mold walls.
In contrast, the water impingement directly below the casting mold should be increased to get larger fraction of the coarse grains.
In each section we numbered the specimens starting from the center to the outward.
The specimens near border of billet appear in the downside of the figure were taken at the line separate the regions of coarse and fine grains.

By researching the WC-Co alloy micro-structure before and after explosive processing, considerable refinement of carbide grains and cobalt cluster thinning were observed.
As an apt defect generation mechanism, chaotic lattice disorder of tungsten carbide can be consider due to multiple reflections of shock waves at intercrystalline interfaces and grain junction lines.
Thus, being processed with shock waves with 30- 35kilobar intensity, the defect accumulation mechanism of metal-ceramic alloy of WC-Co type is conditioned by a great number of lattice micro-distortions in cobalt, increasing dislocation density, growth of micro-hardness and tungsten carbide grain disorder.
Table 1 – Characteristics of sintered alloy from explosion regenerated WC- Co powder Alloy grade Size of original grains, mm Size of final product grains, micrometers Density g/cm3 Coercive force, KA/m Hardness, HRC Flexural stress, mPa Void volume - pore content up to 50 mcm, % WC-94% Co - 6% 0,8÷1 1÷2 14,6÷15,0 11,9÷13,5 88,5 1500 0,2÷0,3 It is worth mentioning that when the WC-Co powder is exposed to the shock wave processing stage, the grinding duration for the powder processed by explosion is 20 times as short as that for the current grinding technology using drum-type grinding mills; this allows decreasing energy consumption for grinding process by 7.75 megawatt for one aggregate only.

Figure 1 The part drawing of turbine disk Table 1 Simulation scheme Forging way Program number Blank temperature /˚C The die temperature /˚C Sheath temperature /˚C Press speed mm/s Thermal coefficient Of friction Common hot die forging A 1050 350 / 5 0.25 Isothermal forging B 1050 1060 / 5 0.25 composite sheath hot die forging C 1050 350 1050 5 0.25 The simulation results and analysis Temperature distribution cloud figure after the end of the deformation is shown in figure 2 .
As you can see in figure 6,the grain size of area including points P1 and P2 is not very uniform compared with that including point P3 ,and it is obvious that the big grain mixed with small grain, namely there is a mixed crystal phenomenon.
The uniformity of grain size have been greatly improved in the area of P4 and P5 because of the improved deformation conditions and the phenomenon of mixed crystals has been basically eliminated.
Simulation of curture-drvien grain growth by using a modified Monte Carlo algorithm[J].

To date, the most commercially available ZnO-based varistors are sintered ceramics with varistor forming oxide of Bi2O3, the key dopant in the matrix, and grain size inhibitor of Sb2O3.
However, under the as-designed sintering system, with increasing sintering temperature and dwelling time, the content of Bi2O3 phase decreased due to the evaporation of Bi2O3 at high temperature, and the grain size of ZnO increased owing to the reaction dynamics.
This can be attributed to the increased ZnO grain size of the samples after sintered at higher temperature and longer dwelling time.
With increasing ZnO grain size, the grain number in a unit length of sample would decrease, thus the varistor voltage decreased.

The limitations of ceramics materials in the area of low fracture toughness can be assuaged by using various methods of grain and boundary size strengthening.
The varieties of strengthening mechanisms that alter the strength of a material include the mechanism of grain boundary strengthening [12].
The block is typically arranged in a “V,” inline, or horizontally-opposed configuration and the number of cylinders range from 3 to as many as 16.
The review established that the existing techniques, although, present strong a improvement in the fracture toughness of ceramic composite materials, there are still a number of problems, including: relying on the concept that resistance behaviour can be simulated, appearance of some phases that made the problem complex, difficulty in evaluating the initial flaw size, solely dependent on the generation of dislocation around the second-phase particles and those that are only effective when the thermal expansion of the dispersed particle is larger than the matrix grain.
McCauleyand I.G., Batyrev,MultiscaleModeling of Armor Ceramics: Focus on AlON; pp. 1–11 in ARL Tech Report, ARLRP- 337. (2011) [11] H, Conrad,Space Charge and Grain Boundary Energy in Zirconia (3YTZP), J.

The proportion of locally thinned lamella and irregularly bent lamella has increased with the pass number of ECAP.
[4] discovered that the proportion of the spheroidization of θ in high carbon steel had increased with pass number of ECAP at 923 K.
[7], the more the pass number, the more the shift and the more the lattice parameter of α.
The proportion of locally thinned lamella and irregularly bent lamella has increased with the pass number of ECAP.
Ultrafine Grained Materials III Edited by Y.T.

Mechanism Analysis The metallographic structure shows that there are a lot of precipitates at the grain boundary of the adapter strip, and the precipitates present a reticular distribution (Fig. 6).
The precipitates are M23C6, which leads to the presence of chrome-poor areas near the grain boundary, thus greatly reducing the material's resistance to intergranular corrosion and stress corrosion.
The improper heat treatment process of the material results in a large number of precipitates at the grain boundary.
Working in the corrosive medium environment of the marine atmosphere, the corrosion resistance of the material such as pitting corrosion, intergranular corrosion and stress corrosion is reduced, the metallographic structure of the material is abnormal, and the precipitates show a reticular distribution along the grain boundary (in the sensitized state), so the cracks conform to the characteristics of stress corrosion [5] and the cracks are mainly stress corrosion cracks.

Thus, in Nb-containing low-carbon steels very fine ferritic grain size can be produced by nucleation on the closely spaced grain of unrecrystallized austenite.
Figure 4: Effect of grain size on bending fatigue of carburized steels [26].
Fine austenitic grain sizes in carburized cases can be produced by multiple reheating and quenching cycles.
It is anticipated that the number of applications will grow, and the ability to further optimize automotive designs and utilize the higher strengths afforded by microalloying is illustrated by the new suspension designs which utilize both bar and sheet steels in critical components [48].
AlOgab: Austenite Grain-Size Control at Elevated Temperature in Microalloyed Carburizing Steels, Ph.D.