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%SiCw is homogeneous and SiC whiskers are uniformly distributed around the ZrC grains, which inhibit the ZrC grain growth during sintering.
The grain is the finer, the numbers of grain is more in per unit volume, and the pressure on each grain is smaller, so the flexural strength of ZrC-20vol.
Most of the SiC whiskers distribute around the ZrC grain boundaries, only a small part of the small size SiC whiskers are distributed in the ZrC grains.
Almost the SiC whiskers homogeneously distribute around the ZrC grain boundaries, which can effectively prevent the migration of grain boundaries and inhibit grain growth.
%SiCw is mainly fine-grain strengthening and whisker pull-out.

Dependence of the impact strength of the welded seam metal on the number of repairs at +20 °C: seam thickness 6 mm; - - - - seam thickness 12 mm.
It consists of small grains of ferrite (light areas) and a small amount of perlite (dark areas).
All these areas are characterized by grain heterogeneity.
Surface layer at laser cutting, the grains size, x500.
Elsukov, Study of the effect of welded joint repairs number on its mechanical properties, Bulletin of SUSU.

An average grain size is 80 μm.
The measurements were performed with an accuracy up to 0.01 mm with numbers of loading cycles N recorded.
The cracks develop transcrystallinearly through grains of the phase α, and also along the grain boundaries.
Variation of the crack length depending on a number of cycles of loading changes according to a = f (N).
Fig. 4 Crack length versus number of cycles N Conclusions The following conclusions can be drawn on the basis of performed tests and obtained results: 1.

However, the decreased grain sizes can lead to an increased rate of hydrogen absorption by metal polycrystals.
Samples of the alloy in the initial fine-grained (FG) state were previously annealed at 1023 K for 1 hour.
Individual grain and subgrains are visible on the dark-field image (Fig. 1, b).
Quite a number of reflections uniformly spaced on a circle are observable in the microdiffraction image of such a structure recorded from the area of 1.4 µm2 (Fig. 1, a).
Such a type of microdiffraction is typical for ultrafine-grained materials with high misorientations between the elements of grain/subgrain structure, nonequilibrium grain boundaries, and internal fields of compressive stresses.

Different numbers of peen passes were selected corresponding to 200 and 300% coverage, along a single peened line (Fig. 2).
Also, texture induced during production and a large grain size can also contribute to peak broadening.
The grain size was typically around 20 μm, determined by electron backscatter diffraction (EBSD) [13].
As we discussed previously, Al2024-T351 plates are produced by rolling leading to elongated grains, i.e. texture.
· Increase in energy of the laser pulses and number of passes induces higher compressive strains

LSP has been proved effective in improving material fatigue strength in a number of alloys [16-18].
The underlying mechanism may include: (i) deformation localized in shear bands consisting of an array of high density dislocations; (ii) dislocation, annihilation and recombination of small-angle grain boundaries separating individual grains; (iii) a change in the direction of the grains with respect to their neighboring grains, becoming completely random.
Furthermore, it can be seen that the ultra-fine grain sizes were nearly the same with that before annealing and the obscure grain-boundary became distinct.
It comes to the conclusion that, for LSP produced ultra-fine grain, the energy offered during annealing at 623K was not high enough to lead ultra-fine grain boundary migration.
The ultra-fine grain presents a barrier to dislocation movements, causing the dislocations to pile up and counteract at the ultra-fine grain boundary.

Two coarse-grained granitic rocks - charnockite and biotite granite – were studied with the aim of estimating their unconfined compressive strength from simpler non-destructive test values.
A set of properties – colour, grain size and shape, strength and durability – characterizes a rock.
Among the commonly used parameters are ultrasonic pulse velocity [2] and Schmidt hammer rebound number [3].
Near-surface moisture contents of coarse grained rocks like the charnockite can lower the rebound readings appreciably.
The number of samples used in rock study is usually hardly representative of the rock mass in question.

The transmission electron micrograph of the ASB in forged and rolled TA2 showed the grain size reduction from ~20µm to 200nm.
This indicates that the ASB consists of fine grains of α-Ti and the α-Ti→ β-Ti transformation did not occur.
A number of quasi-static loading rate studies on this material have been carried out by means of various numerical, analytical and experimental methods, and their results have been published [3、 4].However, the data obtained for this material at dynamic loading and with high strain rates is scanty.
The grain size reduction is of great degree in ASB (from ~20µm reduced to as small as 200nm).
This indicates that the ASB consists of fine grains of α-Ti and the α-Ti→β-Ti transformation did not occur too.

The non-crystalline BN appears in boundary or grain of CrN and prevents CrN grain growing.
The films is composed of CrN nanocrystalline grains with the mean size from 10nm to 20nm.
Amorphous BN and CrB2 compounds exist in boundary or grain of CrN.
The CrN film consists of tightly packed coarse columnar grains, and the CrBN film has glassy packed structure without columnar grains.
Hardness of CrBN films Sample number N content (at.%) B content (at.%) Cr content (at.%) Hardness (GPa) A (CrN) - - - 10.3 B 53.3 6.1 40.5 24.0 C 53.0 15.4 31.6 18.2 D 51.0 19.8 29.2 20.8 E 50.3 28.9 20.8 14.2 The hardness of CrBN films were marked improved because of B attending.

Introduction There are a number of environments for which materials are subjected to dynamic loading [1-4].
In the laboratory environment, dynamic loading can be examined in a number of ways.
Each iteration resulted in a doubling of the number of layers in the composite and a factor of two reduction in individual layer thickness.
The average values of the layer thickness were estimated based on the number of layers and the overall sample thickness.
Some of the nanovoids formed at the vertical grain boundary, while most of them nucleate in the grain interior.