Search results

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.

Effect of alloying elements and impurity (N) on bulk and grain boundary cohesion in Cr-base alloys V.N.
Introduction Chromium has a high melting point (~ 1875°С) that refers it to a number of refractory metals [1, 2].
We chose a special high angle grain boundary Σ5 (210) [100] and a free surface (210) for investigation.
The values of the partial cohesive energy χi for a number of alloying additions to chromium.
The values of the parameter η for a number of alloying elements and impurity N in Cr-base alloys.

Grain Boundary Segregation and Grain Boundary Diffusion of Carbon in Niobium.
Introduction Grain boundary (GB) segregation of a number of microalloying elements like C, P, S, B and others strongly affects the mechanical properties of the structural materials [1].
This fine-grained structure was very unstable and the grains grew intensively during heat treatment.
The optimal grain structure with grains of about 200 µm was obtained by annealing the specimens at 1373 K for 10 hours.
Gust: Fundamentals of Grain and Interface Boundary Diffusion.

Then local textures around holes were estimated in EBSD-OIM system above because the number of grains with orientations of Goss and diagonal-Cube ({100}<011>, D-Cube hereafter) were very small and these grains should then be identified before the TEM observation.
On the other hand, many dislocation densities were observed in grain (c) while their densities were not so high in grain (d) though both grains have D-Cube orientations.
Microstructures in grains after 5% strain; (a) a Goss grain within 6.8 degrees, (b) a {111}<112> grain within 8.0 degrees, (c) a D-Cube grain with 7.3 degrees from ideal one and (d) another D-Cube grain with 14.8 degrees (a) (b) (c) Fig. 3.
Microstructures in grains after 9% strain; (a) a {111}<112> grain with 13.9 degrees, (b) a D-Cube grain with 14.3 degrees, (c) a Goss grain with 12.2 degrees from ideal orientations.
Stripe patterns also can be seen in a Goss grain; grain A is the same as the one in Fig.3(c).

If the fracture stresses in a set of brittle specimens are arranged in size order, the probability of survival of a given sample can be given by the following approximation: 1+ = �n Psurvival (1) Where n is the rank number of the sample and � is the number of the samples in the set (� = 20 in this case).
The EBSD grain orientation map (right) shows failure occurred across a grain rather than at a grain boundary.
A light etch was used to reveal the grain boundaries.
The EBSD grain orientation map (right) indicates a Σ = 19 grain boundary with misorientation 38.3˚ vicinity of grain boundaries.
Fracture toughness of grain boundaries in mc-Si as a function of grain misorientation.

When the internal oxidation reaches to 1000℃, the matrix grains begin to appear annealing twins.
The metallic oxide particles exist diffusely in the matrix grains with equixial shape.
With the increasing of the internal oxidation temperature, the grains grow up obviously.
When the internal oxidation temperature reaches to 1000℃, the matrix grains begin to appear twins.
The arc erosion surface shows a large number of paste-like coagulum and bubbles.

Microscopic residual stresses within a grain were investigated in order to clarify the constraint of deformation by grain boundary.
The grain boundary exists at the central portion of two crystals.
We observed that the line width is large at the grain boundary and decreases in the region apart from the grain boundary.
In spite of a small number of data points, it can be seen that residual stresses in three crystals are clearly different from each other and a tri-axial state was observed.
Acknowledgement This work was supported by JSPS KAKENHI Grant Number 210095.

Implications for grain boundary engineering are mentioned.
The number of papers containing data on different grain boundaries is very limited.
A large number of good quality bicrystals is needed for such measurements and their preparation is a requisite condition for systematic research.
(I) Since the Burgers vectors belong to two different crystals separated by the interface, the expression above indicates only the number and types of dislocations but not the specific crystallographic directions.
Watanabe, T.: in Grain Boundary Engineering, ed.

Above seven extrusions the grain size decreases and grains seem to be broken.
Sharpness of the grain boundaries decreases with increasing pressing number.
It refers the increasing diffusivity of the grain system.
Higher number of pressing caused decreasing in hardness.
Higher number of pressing caused decreasing in hardness. 7.

For that reason, a reference element was considered in order to minimize the number of tests and to maximize the amount of information collected from the test campaign.
The tension parallel to the grain tests consisted in the application of a load parallel to the timber grain's main direction.
Tension parallel to the grain tests.
Table 3: Results of the tension parallel to the grain tests.
A reference element was considered in order to minimize the number of tests.