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The temperature of ECAP not only governs the grain size and misorientation angles of grain boundaries but also the volume fraction of precipitates, thus affecting the probability of twinning and grain growth after fatigue treatment.
Misorientation Number of Misorientations Angle (deg) 0 100 200 300 400 5.4 10.9 16.4 21.9 27.4 32.9 38.4 43.9 49.4 54.9 60.4 65.9 71.4 76.9 82.4 87.9 Misorientation Number of Misorientations Angle (deg) 0 100 200 300 400 5.4 10.9 16.4 21.9 27.4 32.9 38.4 43.9 49.4 54.9 60.4 65.9 71.4 76.9 82.4 87.9 Misorientation Number of Misorientations Angle (deg) 0 100 200 300 400 5.4 10.9 16.4 21.9 27.4 32.9 38.4 43.9 49.4 54.9 60.4 65.9 71.4 76.9 82.4 87.9 (a) (b) (c) (d) Fig.2.
The stress amplitude as function of the number of cycles for the АМ60 alloy ECAPed at different temperatures For the sake of comparison, Fig. 4 shows in addition the published data of the fatigue endurance limit of an Mg alloy with a similar composition (Al 3.8-5.0, Zn 0.8-1.5, Mn 0.3-0.7) and with mean grain sizes of 7 µm and 15 µm [8].
It should be noted that a considerable increase in the dislocation density and the number of twins is observed after the fatigue tests.
Misorientation Number of Misorientations Angle (deg) 0 100 200 300 400 500 5.7 11.3 16.9 22.5 28.1 33.7 39.3 44.9 50.4 56.0 61.6 67.2 72.8 78.4 84.0 89.6 Misorientation Number of Misorientations Angle (deg) 0 100 200 300 400 500 5.4 11.0 16.6 22.2 27.8 33.4 39.0 44.6 50.3 55.9 61.5 67.1 72.7 78.3 83.9 89.5 Misorientation Number of Misorientations Angle (deg) 0 100 200 300 400 500 3.9 9.6 15.3 21.0 26.7 32.4 38.1 43.8 49.5 55.2 60.9 66.6 72.3 78.0 83.7 89.4 (a) σmax= 80 MPa (b) σmax= 90 MPa (c) σmax= 110 MPa (d) σmax= 120 MPa Fig.7.

The idea behind this technique is to develop a simple, economically viable, processing route by using the smallest number of rolling passes, with the largest possible strain per pass.
The material consists of coarse, equiaxed grains of average grain size equal to 95 microns.
Texture data must be interpreted with caution since, due to the large grain size of the starting microstructure, the number of grains measured may not be enough to have a good statistics.
It is well known that the number of active slip systems in Zr alloys is rather high at low homologous temperatures since both prismatic {10-10} and {10-10} as well as pyramidal {11-21} and {10-11} slip systems have been found to be active [12].
Summary In this work the potential of large strain rolling for grain refinement in a coarse grained Zr-Hf alloy has been investigated.

Positron lifetime calculations using the PAW method are highly sensitive to the number of valence electrons in the PAW dataset.
Depending on the cluster size, the number of atoms removed from the cell ranged from n = 1 to n = 40.
Coincidence-site lattice grain boundary Among the enormous number and complexity of grain boundaries, there is a special type known as coincidence-site lattice (CSL) grain boundaries, where several atomic sites from one grain align precisely with those in the neighboring grain.
Compared to random grain boundaries, CSL grain boundaries are thought to have lower energy due to their better atomic alignment, making them an important subject of study in grain boundary science and engineering [29].
In reality, there are an infinite number of possible lattice variants for grain boundaries.

The Damping Effect in the Propagation of the Cracks in Fine-Grained Carbonate Concrete V.V.
At the same time, from a significant number of well-known filler additives, a group of mineral additives can be distinguished with some feature to turn small crack inducing solid areas in the concrete stone into plastic zones displaying damping effect of depriving crucial crack the energy to further growth to full failure of the specimen [5].
From the above brief overview, it follows that a number of researches, design development and production experiences in the application of the additives causing mechanism of damping in the propagation of the cracks products has been accumulated.
Limestone grains ranging in size from 5 to 0.05 mm were used as a filler in fine-grained carbonate concrete.
Modifying of fine-grained concrete by micro and nanodimensional particles of a shungit and dioxide of the titan.

Fundamental Property of Metals - Grain Boundaries Phase Transition as a Basis of Nanostructured Layers, Materials and Composites Production Y.A.MINAEV Leninsky prt.4, Moscow 119049, Russia ymin36@mail.ru Keywords: Grain boundaries phase transition, nitrided coatings, hard metals and steel alloys Abstract.
Introduction For a development of coating technology we focus on the defects on a grain boundaries and description of grain boundaries phase transition (GBPhT) phenomena.
The valuation for a number of metals gives downturn in melting temperature of a surface layer on hundreds of degrees.
On EM micrographs at large magnification it is possible to see inside large carbide grain those fine, which misoriented with matrix "general" grain.
Fine grain has more dark contrast (Fig.3a).

As mentioned above, subgrains were frequently found inside some larger grains.
Micrographs of a larger grain and a subgrain boundary within the larger grain in the HPT Al-0.5Mg alloy: (a) TEM bright-field image of the larger grain; (b) HRTEM [110] image taken from the right frame in (a), showing the sub-boundary formed within the large grain and a SF appearing nearby the boundary; (c) inverse Fourier image from the frame in (b), showing 60° perfect dislocations at a sub-boundary.
A large number of excess dislocations for slip trapped at non-equilibrium GBs (Fig. 3c), as well as dislocations stored near the grain boundaries (Fig. 4), can facilitate grains to slide or rotate at room temperature, and therefore increase the ductility [27].
In the ultrafine-grained (UFG) regime, i.e. grain size in the 100−1000 nm range, the traditional dislocation mechanisms may still remain dominant in controlling plastic deformation.
In the lower nanometer regime having a grain size below 10 nm, deformation processes could be controlled by the grain boundaries, e.g. such as grain rotations and grain boundary sliding.

The samples were further characterized with electron back scatter diffraction (EBSD) to examine the grain size.
Equal channel angular pressing (ECAP) can refine grains effectively and consolidate the powder materials into bulk ultrafine-grained materials (UFG) without residual porosities under low deformation temperature (below the recrystallization temperature).
In addition, the grains are well refined that the average grain size decreases from 0.43 µm to 0.24 µm with the increasing number of ECAP passes.
Shear strain make the majority contribution to the improvement of relative density and coordination number.
The results demonstrate that grains are refined to 0.24 µm by 2 passes of ECAP processing.

There is no significant improvement in alloy after the addition of grain refiners and / or modifiers.
There was no significant improvement in alloy after the addition of other grain refiners and / or modifiers.
There were no significant improvements in alloy after the addition of other grain refiners and /or modifiers.
Fig.4: Surface roughness Ra in µm v/s sample number of Al-Si alloys Drill tool dynamometer readings: The drilling operation was carried out by giving the spindle rpm as 500rpm and depth of cut as 5mm.
[4] Grain refinement response of LM25 alloy towards Al–Ti–C and Al–Ti–B grain refiners by G.S.

At the same time, the grain shape becomes more round as the temperature of airflow increases, and the holes between the grains also become smaller.
Fig. 1a shows that the average grain size was 54 µm, and grain shapes were irregular when the gas was not heated; Fig. 1b shows that the average grain size was 50 µm, and grain shapes were more regular than Fig. 1a when the gas was heated to 50 °C; Fig. 1c shows that the average grain size was 43 µm, and grain shapes were round when the gas was heated to 100 °C; Fig. 1d shows that the average grain size was 39 µm, and grain shapes were more round when the gas was heated to 150 °C.
The number and the size of holes decreases with the growth of temperature.
Where, M is airflow Mach number, M = Vg / ag; Vg is gas velocity; ag is the local sonic.
The grain round progressively and sizes of the hole decreased.

Grain boundary internal friction peak in nan˚Crystalline aluminum studied by continuously changing-temperature J.N.
The IF peak is a grain boundary IF peak, which is ass˚Ciated with the diffusive grain boundary of Al/Al.
Nan˚Crystalline materials have many prominent properties owing to their large volume fraction of grain boundaries.
It can be concluded that the IF peak is caused by the grain boundary sliding which is accommodated by the Al/Al grain boundary sliding.
There are a large number of grains with different orientation in nan˚Crystalline aluminum, during the internal friction measurement of periodic stress, grain boundary viscosity sliding constraints and limits, only in the appropriate temperature, i.e., , the internal friction peak appears.