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The mill-annealed alloy with the hardness of Hv340 consisted of the microstructures of a low percentage of β at the boundaries of elongated α grains.
To distinguish the specimens aged at various temperature, the numbers 482, 593, 704 and 760 were attached to the specimens to represent the aging condition.
Moreover, thin α was found to decorate the grain boundaries of the 482°C aged specimens (Fig.3(c)).
Transgranular fine dimple with grain boundary shear was found for the crack propagated normal to the solidified structure (Fig. 7(b)).
It could be that the thickness of α at columnar grain boundaries and the relative discrepancy in strength/hardness between the boundary and grain interior caused premature fracture at columnar boundaries and the lowest NTS among the welds.

Based on the homogeneous deformation assumption, the σ-ε curves of the material are derived from the load vs. displacement curves and the values of the microscopic physical quantities, such as grain sizes, are set to the values of the corresponding physical quantities in the selected view field.
The cylindrical specimen is Ø8×12mm with initial grain size 275µm.
D in the center of the specimen is relatively reliable and can be regarded as the grain size of the whole specimen.
X can be calculated from 1 1 N i i i X A X N = = ∑ (12) N is the number of the element, iA is the area of element i and iX is the recrystallized volume fraction of element i .
The analysis shows: 1) The obtained stress .vs. true strain curves are very reliable. 2) The D in the center of specimen is relatively reliable and can be regarded as the grain size of the whole specimen. 3) The X in the center of specimen is distinctly influenced by friction.

In the case of the G set the grain size from a mean dimension of tens of nm at high silane dilutions (d<30%) to a mean diameter of few nm at low silane dilutions (d>30%).
This evidence indicates the presence of lattice strain in the Si grains, which can be expressed by the difference between the lattice constants of the nanocrystals and of bulk c-Si [13].
It could be supposed that the presence of such a small compression originates from the grain piling up along the not preferred orientations.
Relevant tensile strain of about 3% was instead observed in the case of the G set samples grown at d>30%, probably due to the smaller grain size. 4 In fact, it is known that lattice strain in the nanocrystals is energetically favourable for minimizing the interfacial energy due to defects or dislocations at the grain interfaces [10].
Acknowledgments The financial support of the European Commission through the project NANOPHOTO (contract number 013944) is also gratefully acknowledged.

The billet was rotated about the longitudinal axis by 90° (route Bc) after each pass, the number of passes 4.
Results The SPD processing procedure resulted in a major reduction in grain size, the initial titanium rods having 25 µm equiaxed grain structure which was reduced to 150 nm after combined SPD and TMT processing, as shown in Fig. 2.
The selected area electron diffraction pattern (Fig. 2c) further suggests that the ultra fine grains contained predominantly high-angle grain boundaries with nonequilibrium distorted structure leading to their excess energy [9].
[4] U.S Patent No. 6,399,215, MKI7 C22C14/00; C22F001/18, Ultrafine-grained titanium for medical implants, published April 7, 2002
Latysh et al in: Ultrafine Grained Materials IV , eds., Zhu, Y. et al TMS, Warrendale, PA (2006), p.277

In addition, dielectric properties of β-SiAlON with different grain sizes were measured to confirm the effect of grain size.
Different grain sizes were obtained due to the size difference of starting precursor powders.
Dielectric constant and loss had slight difference between fine grain β-SiAlON and coarse grain β-SiAlON.
Microstructural analysis by SEM revealed equiaxed grains shape for Sm, Y and Yb doped α-SiAlON.
But elongated grains were observed in La2O3 and Nd2O3 doped α-SiAlON materials.

However the workpiece material removed is composed of a large number of grains.
Due to the rapidly large deformation and high temperature in primary shear zone, the structure of grain will changed greatly when the grain flows out the primary shear zone.
The grain will be elongated and the direction of elongation is considerably different with the shear direction defined by shear plane model, as shown in Fig. 1.
The grain change has been observed by some researchers [2-4].
However the grain velocity also changes when the grain is being sheared in primary shear zone and reaches stability after grain flowing out the primary shear zone.

Mechanical properties and number of strikes until bending 30 mm obtained are given in Table 3.
It should be noticed that increasing of rolling surface only of wheel rim has significant disadvantages: considerable value of residual stress, anneal structure with grained carbides, low resistance to appearance and distribution of cracks.
This is drastically explained by structural condition of wheel steel both by a number of structurally free ferrite and dispersion of austenite product decay to ferrite and cementite mixture.
Application of ultra-high heating and cooling speeds when plasma quenching lead to severe crushing of grains (subgrains) developing nanopatterned elements of phase and structural components of steel quenched [15-17].
One of the main reasons of crack resistance increase when plasma processing is increase a martensite dispersion ability what is specified by size reduction of the original austenite grain due to high heating and cooling speeds, as well as with less stay of steel at high temperatures.

On the other hand, more faceted Fe-rich phases are found along the α-Al grains boundary, due to the dissolution of Fe from the stirrers.
Li [12] reported that oxide formed in Al-Mg alloys is MgAl2O4 which can act as potent sites for nucleation of α-Al grain.
However, the presence of the small α2-Al particles decreases the permeability of the slurry, resulting in an increased number of small pores.
With increased stirring time, coarser and more Fe-rich intermetallic precipitates along the primary α-Al grain boundary
Acknowledgment The current work ReCKA was funded by Vinnova contract number 2018-02831.

According as heat treatment period for sensitization increases, the Cr-carbide deposition in the grain boundary and degree of sensitization (Ia/Ir) increased.
Showing these results is due to the fact that the amount of Cr carbides deposited in the grain boundary by sensitization at 650� increases with the sensitizing period increase.
This is due to the fact that Cr carbide deposition generated in the grain boundary by sensitization rapidly increases until 4hrs, however, after 6hrs, Cr carbide deposition decreases by C reacting with Cr decrease.
Electric potential slowly increases with number of corrosion fatigue cycles increase, but becoming failure cycles, rapidly increases.

The distribution of residual stresses depends also on the phase arrangement and shape of grains.
Grain boundary structure was observed using transmission electron microscopy (Tecnai G2 FEG).
The number of samples was 40.
In A9/Z1 material crack meandering from one to another zirconia grain (the light grains present at the sample edge).
Cracks rarely deflect, mainly went through oxide grains.