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Grain growth occurs as the result of grain boundary migration.
Grain Growth Activation Energy of Yttria.
Large number of nuclei and small grains may be obtained in the early stages of amorphous yttria converted to cubic yttria, in which the nuclei and small grains are closely interdependent.
In the second condition, once larger grain is form, the grain surface energy becomes relatively low and the interconnection between the larger grains become more difficult.
Thus, in the midanaphase stage of grain growth, the main mechanism of grain growth is the thermal diffusion of structural unit to grain suface and its oriented arrangement.

GRAIN ORIENTATIONS AND THEIR INFLUENCE ON PRECIPITATION IN HOT COMPRESSED COLUMNAR GRAINS IN ELECTRICAL STEEL H.
The 0°-sample possesses nearly only four grains and with the angle increasing, grain number in samples increased.
Thus the 90°-sample contains most grains in the form of a series of stacked grains from the top to the bottom of cylindrical sample, but the length of grains became shorter.
Two large grains were detected mainly in this sample.
The misorientation angles in <111> grains are larger than those in <100> grains, but not significantly at 50% hot compression.

In this work, the grain-boundary cavitation in polycrystalline aggregates is investigated by means of a grain-scale model.
The formulation is presented within the framework of a grain-boundary formulation, which only requires the discretization of the grain surfaces.
Grain-scale model including grain-cavitation Any comprehensive micromechanical model of creep should take into account crystal visco-plasticity and grain-boundary cavitation and sliding, which play different roles in different stages of creep evolution.
The basic grain-boundary formulation is briefly presented here.
Finally, is the number of constituent grains of the aggregate.

grain boundary phenomena.
On the other hand, the effect of grain boundaries on bulk properties has been studied and utilized so far by mainly focusing on the grain size, i.e. the density of grain boundaries.
The fully computerized SEM-EBSD/OIM technique has been widely being used for rapid/precise orientation determination or miscroscale texture analysis, and the characterization of a huge number of grain boundaries (say a few tens of thousands) in a polycrystalline sample.
There are a number of promising structural materials expected as future high temperature materials, but hindered from their development because of their intrinsic brittleness due to a high propensity to intergranular fracture.
Relationship between Texture and Grain Boundary Microstructure Since a grain boundary is geometrically characterized by the relative orientation relationship of adjoining grains, it is feasible that any local change of the orientation distribution of grains (local texture) must directly affect the grain boundary character distribution (GBCD) and the heterogeneity of grain boundary microstructure.

Grain Refinement on AZ31 Manesium Alloy by Highly Strained and Annealed Method A.
Grain sizes after the solution heat treatment were about 20 to 150 µm.
Small grains of about 1 µm have been achieved by these methods.
Number density of inclusions were larger in AZ31(Mn) alloy than that in AZ31 alloy.
Precipitates formed in the alloys suppress grain growth, especially those in the AZ31 alloy containing manganese seem to have a higher redissolution temperature and lead to fine grained structure.

These are if some grains with many more facets than the other grains, or if only some grains with a pin up force caused by precipitates at grain boundaries just the half value of the pin up force to stop grain growth or if the mobility of large grains is significantly high than that of small grains.
A huge number of simulation experiments have demonstrated that there are only three ways to achieve the goal as followings.
The special orientated grains with low grain boundary could be the grains with twin grain boundary or coincident lattice site grain boundary.
The local high restored strain energy will give extra driving force to cause partial abnormal grain growth to introduce a number of separate big gains in the matrix of nano-size grains if the plastic pre-strain is carefully controlled to form different local strains.
The special orientated grains could be the grains with twin grain boundaries or coincident lattice site grain boundaries. 3.

The present paper investigates the evolution of the WC grain size and morphology with the number of produced parts.
When analyzing the size of the WC grains, it appears that the population of small grains increases with the number of produced parts until 150.000.
A wear mechanism is proposed to explain this variation of WC grains size with the number of extruded parts.
The percentage of grain size in the range 0.9 to 2.6 is increased but the number of large grains is decreased.
Nonetheless these percentages are lower, meaning that the number of medium grains has decreased.

Simulation of Grain Growth Under the Effect of Stress F.
Through grain boundary engineering [1], certain populations of grain boundaries are enhanced thus a grain boundary character distribution is favored [2].
Recent three dimensional grain growth simulation with anisotropic grain boundary energy was successful in replicating the experimental observations of grain boundary character distribution [6].
It is clear that stress changes the evolution of the grain boundary network during grain growth.
Use of facilities provided by the MRSEC at CMU under NSF grant number is DMR0520425 is also gratefully acknowledged.

Mechanical Properties of Ultra-Fine Grained Al-Li Alloys B.
During 8 passes of ECAE process, coarse grain microstructure in the initial state transforms into ultrafine grained.
In these pictures, deformed and highly elongated grains are visible.
As the number of passes increases from 4 to 8, a development of grain-like structure (Fig. 3b) and a slight refinement of the grain size are observed.
In this term, the grain elongation factor α, defined as a ratio of the maximum diameter of the grain to its equivalent diameter was analyzed.

Introduction Within the last decade a number of x-ray diffraction methods have been presented for non-destructive 3D characterization of polycrystalline materials. 3DXRD [1] and Diffraction Contrast Tomography [2,3,4] are examples of such methods providing full spatial and crystallographic information of the individual grains.
Furthermore, spatial moments of the individual grains are obtained.
Note that each grain will give rise to as many matches as the number of times the grain diffracts within the ω-interval.
If there is agreement between the simulated grain candidates and measured data, the grain candidate is accepted as a grain.
Kinetics of individual grains during recrystallization.