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It was found that the grain size reduction of the material, which was processed using a die with an angle of 90°,wassignificantly more than that of a die with angle of 120°for the same numbers of ECAE.
It was also mentioned that the specimens processed with route A had an elongated and banded structure and those with route C had larger number of equiaxed grains.
As received after the 2nd pass after the 4th pass after the 5th pass Fig.6: The microstructures of the extruded specimens at a magnification of 200 Fig.7: Variation in the grain size versus the number of passes Table 1: The Grain size of the material for different passes Sample ASTM micro-grain size number (n ) The number of grains per square inch (N ) Average grain size (µm ) As received 6 32 45 The1st pass 8 128 22 The2nd pass 8.6 369 13 The3rd pass 11 1024 8 The5th pass 13 4096 4 The6th pass 14 8192 2.8 The Fracture Toughness The toughness is a measure of the amount of energy a material can absorb before fracturing.
The impact energy absorption varied cubically with the pass number.
The impact energy absorption varied with respect to the number of passes.

The thin normalized strip was composed of large columnar grains and small equiaxed grains.
Goss grains were very few.
In addition, the number of Goss nucleation in the deformed {111}<112> matrices was more than that of the {111}<110> matrices.
For the misorientation distribution of grain boundaries (Fig. 4c), both Goss grains and matrix grains showed heterogeneous distribution, but the fraction of 20~45° HE grain boundaries surrounding Goss grains was apparently higher than the matrix grains.
During the intermediate annealing, Goss grains were mainly nucleated in the shear bands within the deformed {111}<112> and {111}<110> grains, and the number of Goss nucleation in the deformed {111}<112> matrices was higher than that of the {111}<110> matrices. 2.

This paper examines the fabrication of ultrafine-grained materials using high-pressure torsion (HPT) where this process is attractive because it leads to exceptional grain refinement with grain sizes that often lie in the nanometer or submicrometer ranges.
Thus, Fig. 4(b) shows the presence of larger grains in the center of the sample and smaller grains at the edges.
More experiments are now needed to determine the effect of straining to higher numbers of turns.
These results confirm the gradual transition to a reasonably homogeneous hardness distribution with increasing numbers of turns.
Langdon, in: Ultrafine Grained Materials III, edited by Y.T.

A number of devices, such as direct shear apparatus and simple shear apparatus, have been employed to study the behavior of interfaces [1-4].
Load controlled simple shear tests were presented in this paper, total number of 20 cycles was applied at a frequency of 0.5 Hz.
Fig.3 Relative displacement curves along the shear cycles As shown in figure 3, it can be concluded that the amplitude of the relative displacement due to the shear deformation of the coarse-grained soil δ2-5 and relative displacement on the interface δ1-2 reached the peak value in the first cycle, respectively, and then reduced until stabilized at a lower value as the number of cycles increased.
The amplitude of the tangential displacements reached the peak value in the first cycle, and then decreased gradually along the number of the cycles; after a certain number of cycles, the tangential displacement stabilized at a lower value.
It can be observed that the variation of the relative displacements followed the similar rule as that of the tangential displacements did, that is the relative displacements reached the peak value in the first cycle, and then decreased gradually along the number of the shear cycles, and after a certain number of cycles, the relative displacements stabilized at a lower value.

Role of Σ9 Boundaries in Abnormal Grain Growth of Goss Grains in Fe-3%Si Steel Approached by Solid-state Wetting.
In the previous approaches are based on the high mobility grain boundaries shared by Goss grains with other matrix grains.
Szpunar et al. [4]have proposed that Goss grains have a large number of high-angle grain boundaries with misorientation in 20-45o range.
In this mechanism, if Goss grain has a high fraction of low energy grain boundaries with matrix grains, it has high probability to occur SSW and grow abnormally.
Goss grain boundaries have low energy relations with CSL grain boundaries.

Solute Interaction in Grain Boundary Segregation and Cohesion LEJČEK Pavel Institute of Physics, AS CR, Na Slovance 2, 182 21 Praha 8, Czech Republic lejcekp@fzu.cz Keywords: Interfacial segregation; Grain boundary embrittlement; Solute interaction; Modeling Abstract.
Introduction Most of the materials used in technical practice (e.g. steels, duralumin and nickel-base superalloys) are complex alloys composed of a number of elements.
Under attraction (aIM>0) the grain boundary is enriched by I.
In fact, increasing XIGB enhances the number of the strong M–I bonds and the number of the weakened surrounding M–M bonds increases thus increasing the probability of the embrittlement.
Lejček: Grain Boundary Segregation in Metals (Springer, Heidelberg, 2010)

New grains are placed at the split grain area and their new boundaries are found.
A number of grains is assigned to the particular phase (ferrite) of the modelled metal microstructure to capture the main statistical properties of the real specimen.
The remaining grains are used for modelling of the austenite grains.
The small white adjacent grains are put together to represent bigger grains with irregular shape.
Table 1: Measured and modelled results Measured sample Mathematical model Ferrite Austenite Ferrite Austenite Number of grains 543 85 543 85 Percentage of surface [%] 48,6 8,06 48,5 8,58 Average grain surface [μm2] 4,84 5,12 4,82 5,12 Median of grain surface [μm2] 1,13 3,77 1,12 3,78 Biggest grain surface [μm2] 95 27 92 26 At the Fig. 4 b) there is the final mathematical model.

It is to be noted that columnar grains are still present in the grain refined sample.
The grain size of non-grain refined alloys (Al-0.8% Mg and Al-4% Cu) was calculated to be 800-900 µm (Fig 4 (a and c)), whereas grain refined alloys have grains 300-400 µm in size (Fig 4 (b and d)).
Grain size of reference and grain refined alloys were reduced significantly.
Nucleation efficiency refers to the effectiveness of a given type of inoculant with specific physical characteristics and solidification conditions, such as number density, size distribution and cooling rate.
Similarly for the MgAl2O4 between 200 nm and 2 µm in size, number density was approximated to be between 108 and 1010 particles/cc.

Martensite transformation starting (Ms) temperature decreased with increasing the number of the ARB process.
In the martensite transformation, the size of grain after the phase transformation is significantly smaller than that of the austenite, because a number of new grains with different crystal orientations (martensite variants) evolve within individual austenite grain.
The lamella spacing decreased with increasing the number of the ARB cycles (i.e., strain).
%Ni alloy as a function of the number of the ARB cycles.
The tensile strength increased with increasing the number of the ARB cycles.

We got L415 Pipelines’ coarse grained region of different heat inputs and post-treatments by welding thermal simulation, researched microstructures, hardness, impact energy and fracture, the result showed that, when the heat input is 25KJ/Cm, followed by annealing treatment with temperature 700℃ for 1 hour, we can get good mechanical properties of coarse grained region.
To solve this contradiction, In this article, we take L415-level pipeline steel in the coarse grain zone as the research object and use welding thermal simulation technique to simulate effect on the properties in the coarse grain zone of L415-level pipeline steels under different welding heat input and heat treatment after welding.
Welding heat input thermal simulations of 17KJ/Cm, 20 KJ/Cm, 25 KJ/Cm were performed on a Gleeble-3500 thermal simulator, then were post-treated as 700℃×1h, 570℃×1h, AW(as welded) respectively, got coarse grained region’s thermal simulation specimen of different heat inputs and post-treatments, numbered each group specimen as A,B,C,D,E,F,G,H,I (see Table2).
Table 1 The chemical constituent of L415 pipeline steel Material C Mn Si S P Cr Ni Mo V Ti Nb L415 0.113 1.56 0.299 0.003 0.009 0.078 0.034 0.116 0.087 0.014 0.025 Table 2 thermal simulation of different heat inputs and post-treatments Heat input Post- treatment number Heat input Post- treatment number Heat input Post- treatment number 17KJ/cm 700℃×1h A 20KJ/cm 700℃×1h D 25KJ/cm 700℃×1h G 570℃×1h B 570℃×1h E 570℃×1h H AW C AW F AW I Experimental Results and Discussions Microstructure Observation Coarse grained regions’ microstructure of different heat inputs and post-treatments under the amplification of 500X (see Fig.1).
The change of coarse grained region’s impact energy (see Fig.3) showed that coarse grained region’s impact energy when 700℃×1h is the highest. when the heat input is 25KJ/Cm, followed by annealing treatment with temperature 700℃ for 1 hour, the impact energy is highest and at 260J.