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The results indicate that hot corrosive gas mainly causes the strength reduction because of the degradation of grain boundary region.
It is thought that inorganic additives are reacted with SiO2 existing on the surface of each SiC grain at the sintering temperature and thus bonded with another SiC grains [5,6].
Table 2 - Characteristics of porous SiC filter Figure 3 plots strength as a function of number of thermal cycles on SiC plate filters.
Therefore the number of thermal cycle exactly means duration time at 850 oC.
Fig. 5- Strength of SiC plate filter Fig. 6 - Strength of SiC plate filter as a function of number of thermal as a function of number of hot shock cycles.

For single pass the general form of the shear strain is given by [17]: , so that (7) where N is the number of passes.
The microhardness profile across the HPT disk for various numbers of turns is shown in Fig 6c.
By contrast, the grains at the edge are clear and grain interiors are almost dislocation free.
Both within and outside of these zones, the Al matrix grains were equiaxed with well-defined grain boundaries.
This suggests that the Si particles assist in grain refinement in the Al–7% Si alloy by pinning the grain boundaries and inhibiting grain boundary migration.

We can conclude that during processing the ultrafine-grained microstructure in as-cast Nb and Ta was formed.
Immediately after EBM, the metals contain a large number of pores (Fig. 4b).
The deformation-induced formation of dislocations, shear bands, and grain boundaries occurred in the metal at the same time.
Viljus, Processing and properties of bulk ultrafine-grained niobium.
Sursaeva, Review: grain boundary faceting-roughening phenomena.

Mabuchi et al [3] reported that fine-grain Mg alloy with the grain size of 1 µm could be obtained by ECAE, which suggested that ECAE was a valuable method to refine the grain size of Mg alloy.
(1) Where N was the pass number, so the strain of each pass was 1.15.
The ECAE processing refined the grain size effectively, and ultra-fine grains in submicrometer range could be produced by the two-step ECAE.
Careful observation revealed that the grain boundaries are high angle grain boundaries.
In Fig. 2 (b), there are also few dislocations in the interior of grains in spite of large straining by ECAE and effective grain refining.

The decrease of coercivity and remanence with the number of impacts per turn is clear.
The size determine the FM or SPM behavior of the grains, and only the number of grains above the SPM limit contribute to the hysteresis and coercivity [9,10].
If remanence and coercivity are taken as directly related to the number of FM Fe grains, the samples with high ipt should have very few or none of such FM grains or clusters.
A direct observation of the number and size of the clusters can be performed by AFM.
Samples b) and c) have much smaller iron grains.

On a macro-level, the model material can be considered as aggregate grains dispersed in a cement matrix.
In contrast, a finer aggregate system contains larger number of small grains, which subdivide the open space into smaller and less accessible spaces [12].
Gap grading activates the mechanism of 'migration capacity' of fine sand particles into the network structure of coarse aggregate grains; or, analogously, of the fine particles of the mineral admixture into the network structure of the coarser grained Portland cement.
Fig. 2 reveals clearly the effects of the PSD of coarse aggregate grains on the migration capacity of the fine sand particles.
It should be noted that computing time restrictions impose significant limitations to the number as well as the size range of coarse aggregate grains in the simulation study (due to the significantly larger number of fine sand particles that have to be generated in proportion to the mass of coarse aggregate).

Significant dependence of thermal stability of fine ECAP microstructure on number of passes was found.
As a consequence, the samples with higher number of passes were less stable.
Anyway, the difference in stability of the samples deformed by different number of ECAP passes is clear also in the evolution of line broadening (e.g.
However, the problem is that for recrystallization of severely deformed copper a fast grain growth is typical when only a few grains begin to grow quickly while others remain small.
We are not able to estimate grain growth above the limit from the XRD line profile broadening.

Free-machining Cr-Mo structural steel, containing low-melting elements, has ASTM grain size of the number of 7–8.
The investigated steels containing low-melting elements had austenite grain size not larger than of the ASTM number 7 (Table 4).
The investigated steels containing low-melting elements had austenite grain size not larger than of the ASTM number 7 (Table 4).
Effect of tin, lead, boron, nitrogen and aluminium on austenite grain size Steel Element, % [Al], % ASTM grain size number 30KhM  0.04 8 AS30KhM 0.24 Pb 0.03 7 ASTs30KhM 0,23 Pb 0.04 8 AO30KhM 0.07 Sn 0.06 7–8 A30KhMAR 0.008 B, 0.008 N 0.02 7–8 Conclusion 1.
Free-machining Cr-Mo steel of the 30KhM type alloyed with low-melting elements has ASTM grain size number of 7–8.

Hardness measurements were used to investigate the influence of high pressure torsion (HPT) number revolutions on mechanical properties.
The grains were elongated and stretched due to the severe shear strain.
The average crystallite size plotted versus number HPT revolutions Figure 12.
The calculated dislocation density plotted versus the number of HPT revolutions Hardness Figure 13.
Mechanical properties of an ultrafine-grained Al-7.5 Pct Mg alloy.

This deformation is caused by a number of creep mechanisms, such as dislocation glide and climb, grain boundary sliding and diffusional processes.
These particles and defects can be depicted by their type, shape, arrangement and number densities [7].
Grain boundaries have a distinct influence on these reacting internal stresses, resulting from the discontinuity of elastic properties across the grain boundary [9].
In this work, a special focus is set on the interaction of grain interior, grain boundaries and triple points.
Adjacent grains are separated by grain boundaries.