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The magnetic behavior of this material is controlled mostly by the final average ferrite grain size.
The microstructure and mechanical properties resulting from annealing cold rolled semi-processed GNO electrical steel depend on a number of processing conditions.
As can be seen, annealing during 60 seconds causes full recrystallization and grain growth.
On the other hand, faster heating at 30 °C/s decreases the total time available for recristallization and growth of the ferrite grains and produces a smaller grain size.
As can be seen, on the average, the ferrite grains have very similar sizes (9.2 vs 10.7 µm) and there is a smaller number of particles precipitated at grain boundaries and within the grains in the former material.

Introduction The mechanical properties of metals are determined by a number of factors but in practice the microstructural characteristics of the materials, and especially the average grain size, play a dominant role.
To avoid these uncertainties, it is easier in practice to adopt a procedure in which the strain is specified simply in terms of the number of turns, N, imposed on the sample [17].
The Nature of Grain Refinement During Processing by ECAP When metals are processed by ECAP, the microstructural characteristics depend upon the processing route and the numbers of passes through the die.
These increases in strength are consistent with the reductions in grain sizes from ~15-50 µm in the alloys prior to pressing to average grain sizes of <1 µm in all alloys after processing by ECAP.
The data in Fig. 10(b) show the maximum elongations are displaced to faster strain rates when the alloy is processed to larger number of passes, where this displacement occurs because the fraction of high-angle grain boundaries generally increases with increasing numbers of passes through the ECAP die [33].

Although surface hardness of SFAP is decreasing with grain size number increasing, surface hardness of SFAP in different grain size is no evident distinction.
While in the same 65 wt% abrasive weight percent, Young's modulus of SFAP is decreasing with grain size number increasing, as Fig.11 shows.
It because that bond strength between abrasives in SFAP is decreasing with grain size number increasing, so it influences the Young's modulus of SFAP.
SFAP of 50 wt% abrasive had more bonding material and a small number of pores.
And with the same abrasive weight percent, shearing strength of SFAP is decreasing along with grain size number increasing.

The grain size is erratic with elongated grains mainly in the centre regions.
The grain structure shows very large, slightly elongated grains at the centre, with equiaxed grains present at the edge.
The grain structure shows a small area of elongated grains in the centre, surrounded by fine equiaxed grains, although larger grains are situated at the edge.
Conversely the elongated grains present in the central region of both structures are more pronounced in specimen S2.4-650, where a lower annealing temperature has resulted in a lower number of recrystallised grains forming here.
The grain structure of specimen S2.4-750 shows large, slightly elongated grains at the centre, with equiaxed grains present at the edge.

Since the early 90’s, number of research activities are carried out in the field of micro forming and micro extrusion.
The average grain size of the copper is 38 μm.
It is noticed that the grain size increases with the increase of working temperature and the grains are unevenly distributed in the billet.
Due to the presence of a large number of grain boundaries, the hardness is higher and requires higher deformation load and flow stress (Fig. 6) when compared to the heat treated metals.
During the process, it is observed that the grain refinement is possible only for a limited number of passes beyond which crack will propagate over the surface.

However, one cannot find large number of good works in this context.
There are a number of mechanisms to reduce the overall surface energy.
If the number of long necks is much larger than the inter-grain contacts, they control the conductivity of the gas-sensing material and define the size dependence of the gas sensitivity.
For simplicity, the sensor element is presented by a one-dimensional chain of SnO2 crystallites which are connected by a predominant number of necks and a small number of grain boundary contacts.
At some critical dimension, the number of free electrons in the grain could become zero even at Vs = 0.

The subsequent electropulse treatment furthers transformation of the grain structure since grains arise and grow due to evolving local dynamic recrystallization and partial transformation of the dislocation substructure and occurrence of a great number of microtwins.
Besides the above dislocation substructures there are grains (25-30% of the total number of grains) with a few dislocations.
The letter A points at the grain with a low scalar density of dislocations.
The grain structure is transformed – grains arise and grow due to the evolving local dynamic crystallization.
The further electropulse treatment is the reason for grain structure transformations since grains arise and grow due to the evolving local dynamic recrystallization and partial change in the dislocation substructure, as well as because of a great number of micro-twins.

The yield stress and the fracture stress increase with decreasing grain size.
The effect of grain size on the yield stress of magnesium and its alloys has been reported in a number of studies, e.g. [4-10].
The yield stress and fracture strength increase with decreasing grain size.
The grain size dependence of the yield stress σy can be expressed according to the Hall-Petch relation: σy = σ0y + kyd -1/2 (1) where d is the grain size, σ0y and ky are constants.
Strength and fracture of magnesium alloys is influenced by grain size.

The previous work [8] has demonstrated that superplastic behavior of the ultrafine-grained base material and the ultrafine-grained stir zone material was distinctly different.
The grains contained a poorly developed substructure consisting of nearly equiaxed sub-grains, with a mean size of ~0.5 mm.
The microstructure was dominated by nearly equiaxed grains with the mean grain size of ~0.9 mm and HAB fraction of 78%.
This presumably indicates abnormal grain growth.
Acknowlegement The financial support received from the Ministry of Education and Science, Russia, under Grant No. 14.578.21.0097 (ID number RFMEFI57814X0097) is gratefully acknowledged.

Vanadium is added to commercially pure Al as a grain refiner resulting in small grain size and improvement in its mechanical behavior and wear resistance, [5].
This may be attributed to the increase in the number of grains due to the refining effect and the activation energy of the corrosive media as follows: 1- Increasing the number of grains per unit area will cause more intergranular boundaries (surface area) exposed to the corrosive medium, this resulting in increasing the corrosion rate. 2- Increasing the temperature increases the activation energy of the corrosive media, thus promoting more attack on the solid surface through increasing the diffusivity of hydrogen ions towards the Al surface.
It shows the grain refinement effect of 0.112 wt % vanadium addition.
The grains are much finer than those of commercially pure Al (figure 6).
It shows that the grains and its boundaries are wiped off.