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This unusual behavior of deformation bands and their features depending on the grain size are discussed.
Moreover, there is no general line for the effect of the grain size reduction on the jerky flow.
This result may be related to an increase in the number and strength of obstacles to the motion of dislocations due a combined effect of both grain refinement and nanosize particles, which locally harden the material and generate internal stresses promoting plastic flow in the neighboring areas.
Summary In summary, the PLC effect was investigated in an Al–Mg–Sc alloy with two grain sizes.
Lloyd, H.Jin, Inhomogeneous yielding and work hardening of a fine grained Al–Mg alloy, Mater.

Note that the peak intensity of the γ-Fe phase increases with the number of pulses, indicating that the volume fraction and/or grain sizes of the γ-phase increases with increasing the number of pulses.
As shown in Fig. 3(a) , very fine grains with sizes of 100 nm approximately are homogeneously dispersed on the whole irradiated surface, clearly indicating that the melted surface layer are mainly composed of refined grains or subgrains.
It is worth noting that the interiors of fine grain appear to be clean without any detectable defects.
They are often present at the grain boundaries and triple junctions.
Figure 4 Surface microhardness of samples with different pulse number after HCPEB irradiation Figure 4 shows the microhardness changes of 3Cr13 steel before and after HCPEB treatment.

The copper tubes annealed at 780℃ have finer grains and slightly poorer grain uniformity.
The average grain size is 11.45 μm if a twin crystal is considered as a grain.
The average grain size is 22.35 μm if a twin crystal is considered as a grain.
(a) 780℃ grain boundary (b) 810℃ grain boundary (c) 780℃ intragranular image (d) 810℃ intragranular image Fig. 4.
It is known that the 810℃ annealed tube contains a large number of low stacking fault energy twin boundaries, which belong to Σ3 grain boundaries.

Since the ceramics densification process and grain growth is a contradiction, the preparation of micro-nano grained ceramics with high relative density remains an challenge[2-4].
The change of grain size needs to be further proved by the SEM.
Table 2 is the relative density, grain size and other parameters.
Through the longitudinal comparison, it is found that only using the 400 nm powders in the 400 nm series, the ceramics grains are not fully developed, still spheroids, and a large number of pores are present around the grains, indicating a low degree of densification (Fig. 4a).
Utilizing the combination of 400 nm+200 nm, the ceramics grains are fully developed, the morphology is a polyhedron with clear boundaries, and coexisting large-sized grains and small-sized grains (Fig. 4b).

This becomes possible due to high green density and the presence of a large number of fast diffusion paths associated with dislocations and grain boundaries.
We were guided by previous experience that the temperature of sintering required after direct compaction of BE powders by ECAP can be reduced due to high green density and the presence of a large number of fast diffusion paths associated with dislocations and grain boundaries [6].
In the case when MA1 particles were used, samples exposed to the two temperatures exhibited similar microstructures characterised by globular and equiaxed α-phase grains with elongated β-phase at the α grain boundaries and accumulated β-phase at α triple junctions, Fig 5 (a) and (b).
The number of α-phase nuclei formed at the grain boundaries depends on the grain size and therefore, a smaller number of nuclei per grain were available due to concurrent ECAP grain refinement, Fig. 6.
(Ultrafine grains ~100-200 nm in size and a high dislocation density can be seen.)

Introduction Grain refinement is an important process to increase the strength of metallic materials.
However, it is generally difficult to achieve combined effects of both grain refinement and fine dispersion of precipitates.
Provided that such a supersaturation is achieved in an ultrafine-grained alloy, another important task is to make fine precipitation within the fine grains by subsequent aging while keeping the grain size small.
The hardness increase is faster with increasing number of the revolution as reported in other metallic materials [10-12].
(3) Simultaneous hardening due to aging and grain refinement was attained in the 2091 alloy.

from the grain surface towards the neck formed between two grains.
Here, the neck growth of two spherical grains of equal radii r=0.2 is investigated.
The case investigated here concerns two grains in contact.
The fact that each grain has its own material properties is an additional difficulty: each grain (or group of grains), must be described by its own a level set function.
An Eulerian description of the problem where the ceramic grains (without restriction concerning the number of grains), evolving in a fixed adapted mesh, are described by using a level-set method is the key point of the numerical simulations.

The evolution of the microstructure from porous and columnar grains to densely packed grains is accompanied by changes in mechanical and physical properties.
Ion bombardment during vapour deposition of thin films, colled ion beam assisted deposition (IBAD), exerts a number of effects such as densification, changes in grain size, crystallographic orientation, morphology and topography of the films.
Therefore, in recent years, a number of measurements have been made in which nanoindentation and AFM have been combined.
Therefore, in recent years, a number of measurements have been made in which nanoindentation and AFM have been combined.
Indeed, there is a preferred growth of the biggest grains on the densest plane, in order to minimize the surface energy.

The latter considers different kinds of recrystallization as the same process rooted in nucleation and grain growth.
The number of nuclei per volume unit NV corresponds to the number grain per volume after full recrystallization, whereas number of nuclei per volume unit NV can be easily calculated from the final grain size after metadynamic NVmd = f(Dmd) or static NVsrx = f(Dsrx) recrystallization.
An equation for nucleation rate can be presented in the form: , (5) where: - the nucleation rate during static recrystallization [mm-3s-1], NVmd - number of grains per volume unit after metadynamic recrystallization.
Growth of recrystallized grain can be calculated according to following differential equation: , (6) where: DS – grain size [mm], - grain growth rate [mm/s], Ddrx - dynamically recrystallized grain size [mm].
Identification of model parameters For the model parameters identification, a nonlinear least-squares (nonlinear data-fitting) problem with constrains must be solved: , (9) where: n – a curve number, i – a point number, pn – a weight of the curve with the number n, kn – a number of the points on the curve with the number n, l – a number of the curves, σmni, σcni –flow stresses for the point number i on the curve number n, measured and calculated respectively, σnmax – a maximal value of the flow stress for the curve number n.

A number of electrodeposited alloys are of interest due to various properties.
At low temperature, the grain is decreased and the grains began to adhere and grew together.
A greater number of grain boundaries with the highest proportion of atoms inside the boundaries created an extremely high volume fraction of grain boundaries in the CoNiFe microstructure [9,10].
At higher temperatures (>700oC), the coating began to soften as the grains conglomerated and reducing the number of hardening sites.
The grain size reduction has resulted in the high volume fraction of the boundary atoms inside the grain boundaries.