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Sandglass extrusion is an ultrafine grain size method.
Due to the repetitive and multiple extrusions, large strain can be accumulated and ultrafine grain size can be obtained.
Introduction Severe plastic deformation (SPD) is a kind of method for producing ultrafine grain size material.
This method can produce ultrafine grain size by SPD.
By using of this method, the ultrafine grain size material can be obtained.

The linear method was used to determine the average number of segments per one length unit of the NL structure and the average length of the circuits of grains in the áLñ flat structure.
The NA parameter has an [mm-2] dimension and is defined as a relative multiplicity of particles or grains in a flat structure, i.e. the average number of particles or grains per a unit area (also known as the density of particles or grains on the plane).
Pattern number 6 reflected the image of the structure best, so using the formula (1) it was calculated that the number of grains on the surface of 1 mm2 is 512, and the average áAñ surface area was determined to be 0.001953 mm2 with the following formula:
Based on the measurements for the Armco iron, the average number of grains per one unit of the NA area and the mean surface area of the grains in the áAñ flat structure were determined with the planimetric, the Jeffries and the comparative methods.
The linear method was used to determine the average number of segments per one unit of length of the NL structure and the average length of the circuits of the grains in the áLñ flat structure.

The Influence of Grain Size and Grain Size Distribution on Sliding Frictional Contact in Laterally Graded Materials Romik Khajehtourian1, a*, Saeed Adibnazari 2, b, Samaneh Tashi 3, c 1, 2, 3 Department of Aerospace Engineering, Sharif University of Technology, Tehran 14646, Iran ar.khajehtourian@gmail.com, badib@sharif.ir, csamaneh.tashi@gmail.com Keywords: Graded Materials, Micro Scale, Grain Size, Grain Size Distribution, Contact Mechanic.
Also, increasing the grains aspect ratio and using optimum distribution of grains decrease stress distribution roughness on the surface.
In the micro FE model, grains arranged with appropriate volume fractions, randomly. wg, hg and wg/hg, respectively, denote the width of grains, the height of grains and grain’s aspect ratio.
Fig. 6 presents the normalized contact stress σyy(x,0)/(P/(b-a)) as a function of the grain’s aspect ratio with constant grain size distribution.
Thus once again, beginning of surface cracking at much lower number grain’s aspect ratio which causes less endurable surfaces in contact problems and effect of grain size distribution has demonstrated.

In proportion to the logarithm of the extrusion rate, the number of DRX grains increased monotonically.
With an increase in extrusion ratio from 10 to 20, the DRX grain size decreased by 45%, and the number of DRX grains increased.
However, at extrusion ratios of over 20, the DRX grain size hardly changed, and no systematic change was observed in the number of DRX grains.
(Sample No. 2; extrusion rate: 30 mm/min) Fig. 3 shows the variation in fine grain size and number of fine grains as a result of T6 temper.
At an extrusion ratio of 10, a slight decrease in the fine grain size and slight increase in the number of fine grains are observed.

The alloy liquid undergoes non-equilibrium solidification so that a large number of dendritic grains are formed in the melt.
As the temperature decreases, the number of nucleation points in the melt increases, which induces a large number of nucleation of the melt.
There was only a few dimples could be seen on the fracture, instead with a large number of lamellar quasi-cleavage planes, indicating that brittle fracture occurred when the alloy fractured.
As shown in Fig. 5(b), the number of dimples in the fracture, with different sizes and deep dimple depths, was very large.
The grain spheroidizes and the grain boundary becomes rounded.

The number of residual phases and grain size were also counted by Image Plus Pro (IPP) software to complement the validation of homogenization.
Meanwhile, in the high Mg alloy, it is mainly dark brown reticular and light gray phases, and the number of fine precipitated phases near the grain boundaries is significantly increased.
The reason for the high number of Ag-containing Al2CuMg phases in high Mg alloy may be related to the Mg-Ag clusters.
Grain Characteristics during Homogenization.
Furthermore, the grain boundaries become clear, indicating that the grain interior segregation is eliminated.

To avoid this unwanted effect – since the cracks propagate mainly on high angle grain boundaries – our goal was to enhance the number of special coincident site lattice type grain boundaries with thermomechanical treatment.
The grain boundaries which have a given fraction of atoms in the grain boundary plane which are coincident to both lattices separated by the grain boundary are characterized by the Coincident Site Lattice (CSL) model [5].
By increasing the number of the CSL-boundaries better corrosion and fatigue properties can be obtained [2, 5-7].
Fig.6 Crack length and width into the surface versus the fraction of CSL/random high angle grain boundary Conclusions The relative fraction of CSL grain boundaries to the total amount of grain boundaries increased due to the thermomechanical treatments.
Watanabe, Correlation of grain boundary connectivity with grain boundary character distribution in austenitic stainless steel.

The creep property of sandy slate coarse-grained soil under different moisture conditions is analyzed through uniaxial compression creep test on influence rule of moisture content on creep of coarse-grained soil.
It turns out that moisture content is the important factor that affects creep property of sandy slate coarse-grained soil and using dry or saturated coarse-grained soil is able to decrease long-term settlement of embankment.
Limited by topographic condition, a large number of high fill subgrades are emerging continually.
When moisture content is in a low level, coarse-grained soil consists of solid-gas phase.
Fig.5 Stabilizing time constant α of sandy slate coarse-grained soil The Nonlinear Creep.

The maximal absorption rate got 99.81%.The modified brewer's grains of amine surfactant modified is a promising treatment of chromium wastewater biological materials.
Brewer's grains is the main by-product of beer industry.
It have good hydrophilicity and easily adsorbed porous structure, containing a large number of hydroxyl groups.
The metal ion adsorption ability was increased by chemical modification of active groups[3].In the paper, the modified adsorbent was modified by amine reaction with brewer's grains that using epichlorohydrin(ECH) as etherfying agent,N,N-Dimethyl formamide (DMF) as dissolvent, triethylenete tramine(TETA) as cross-linking agent and introduce amino group,so as to utilize the brewer's grains as the low cost material for Cr(VI) wastewater purification, then the results would be the theoretical basis for the comprehensive utilization of the brewer's grains.
Material and Methods Material Preparation of modified brewer's grains biosorbent:The brewer's grains was from the bee laboratory in our school, washed with tap water, and dried at 50 °C to constant weight.

Cavitation behavior during superplastic flow of ultra-fine grained (UFG) Ti-6Al-4V alloy was established with the variation of grain size and misorientation.
Distinct colors indicate the orientation of each grain.
Regardless of the number of ECAP deformation in this study, most alpha-phase and beta-phase grains were considerably refined and fragmented to ≈ 0.3 µm in diameter without changing volume fraction of each phase.
Firstly, the size, number, distribution, aspect ratio and area fraction of cavities decreased in materials with finer grain size and more distinctive misorientation.
proportional to the grain size [5].