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It also results in the grain refining efficiency[9].
It exhibits that great number of gray sheet phase, white polygonal phase and some small acicular phase are formed in the as-cast alloy (Fig. 3(a)).
It is shown that the long sheet Mg12Ce phase in the as-cast alloy break into many small sections and a number of solution Ce, Y, Mn, Ho and Er in the magnesium alloy matrix.
Firstly, after extrusion, the grain size is greatly reduced from 100 μm to 6 μm.
According to the Hall-Petch relationship, the UTS and YS can be greatly improved through grain refining effect.

Effect of La2O3 on the microstructure and electrical properties of 0.82Bi0.5Na0.5TiO3-0.18Bi0.5K0.5TiO3 ceramics Yan Li，Yanjie Zhang, Ruiqing Chu*, Zhijun Xu, Qian Chen, Yong Liu College of Materials Science and Engineering, Liaocheng University, Liaocheng 252059, People’s Republic of China * rqchu@lcu.edu.cn Keywords: Microstructure; Grain sizes; La2O3-doped; Ceramics; Electrical properties.
SEM images indicate that the grain size of the 0.82BNT-0.18BKT ceramics increased with the addition of La2O3 doping.
The average grain size in a 0.82BNT-0.18BKT-La-x ceramics is given by Fig. 1.
XRD pattern of the 0.82BNT-0.18BKT-La-x ceramics (1) In Eq.(1), G, n, Li, and NB each represent the average grain size in the disk, the total number of straight lines drawn on the SEM image(Fig. 4), the length of the ith straight line drawn on the SEM image, and the total number of grain boundaries, which are intersected by all of the straight lines drawn on the SEM image, respectively[20]. 5μm (a) 5μm (b) 5μm (c) 5μm (d) Fig. 2.
However, the addition of La2O3 leads to no obvious change in the feature of grain shape.

The crystallographic orientations of each grain are provided in a random fashion.
(b) – (h) show major seven large grains (G1–G7) extracted from (a).
Fig. 6 depicts the population of the rotation angles from the initial orientation in the grain G6.
Populations of rotation angles from the initial orientation in the grain G6.
The orientation spread and multidirectional rotations in grains were meanwhile reproduced only by the CPFE analysis, in which the influence of interaction between neighboring grains was taken into consideration.

Thermal aging also introduces gamma prime precipitation to the 617 alloy as well as grain boundary carbides, and this, in addition to grain boundary oxidation, reduces the low cycle fatigue strength of 617 alloy compared to 230 alloy.
One can surmise, therefore, that creep strength is not promoted by recrystallization without grain growth.
Cooling rates in the furnace cool or air cool range produced grain boundary carbide precipitation in both alloys.
Alloy 230 showed a dense Cr based oxide scale and some oxidation of Cr and Al limited to the grain boundaries.
The thermal fatigue crack initiation life (TF) was defined as the number of thermal cycles to form a crack of 0.3 mm length.

Vitrified bonded grinding wheels have abrasive grains distributed in the volume of the grinding wheel.
Every single contact of a grain is supposed to generate a stress pulse in the workpiece.
This is caused by the random nature of the signal due to the distribution of abrasive grains in the grinding wheel.
All the measured areas AM increase in a nearly linear way with the number of strokes.
Wright: Siam Journal of Optimization, Vol. 9 (1998), Number 1, pp. 112-147

Modeling of recrystallization and grain growth during the forging process Modeling of microstructural changes during thermomechanical treatments implies the mathematical description of process relevant physical phenomenons such as grain growth and recrystallization.
Of similar relevance regarding the recrystallization process is the possible grain refinement, which has a significant effect on the mechanical properties of the material.
thDD k a o a ⋅=− 15 15 . (12) ),( Kk k XQfh = . (13) 17 5,0 )5,0ln( 1 a e e tt tt k eX         −− ⋅ −= . (14) Eq. 12 shows the typical semiempirical expression for the grain growth with the grain growth exponent a15 and the energy term hk, which is a function of the activation energy for grain growth Qk and the relative fraction of the second phase Xk.
Forging temperatures must be chosen below the δ-solvus to inhibit grain growth during heating and reheating processes.
This means that these regions still show the original but deformed grain structure, which can lead in a coarse grain in the final forging.

Comparing with micrographs shown in Fig. 2, it is notice that fracture feature show no evident inside grain, while, it Fig. 1 LCF properties of GH4586, showing relationships between cyclic numbers to failure with, A) stress amplitude; B) strain and C) logarithm strain.
is quite different in grain boundary between short and long life specimen.
After the larger number cycles, fracture surface has been crushed, while carbides can be clearly observed on grain boundaries.
At this time, the larger plastic deformation is considered due to the larger mount of microvoids occurred inside grain and shear deformation occurred near the grain boundaries (refer to Fig. 2 a)).
Fig. 4 Fracture surface of GH4586 showing the precipitations on grain boundaries.

With growing number of passes the texture type remained the same.
Fig. 4a shows a hardness evolution with growing number of ECAP passes.
Microhardness evolution as a function of a) pass number, b) annealing temperature during isochronal annealing.
Microhardness as a function of a) deformed (sub)grain size, b) annealed grain size at 280°C.
A very fine, relatively equiaxed grain structure (grain size 0.44 µm) was obtained after twelve ECAP passes (Fig. 5).

Therefore, it is necessary to develop a low cost, recyclable and environmentally friendly yacht to replace the current large number of fiberglass reinforced plastics yachts.
People continue to manufacture a large number of FRP yacht products, then discard the old, take up a lot of land resources [7, 8, 9].
Therefore, it is necessary to develop a low cost, recyclable and environmentally friendly yacht to replace the current large number of FRP yachts.
Their modulus of elasticity value (across the grain) is below regular fiberglass reinforced plastics yacht requirements.
Conclusion Regardless of the modulus of elasticity (along to grain) or the modulus of elasticity (across the grain), the predicted model of the composite bamboo yacht material's modulus of elasticity value have highly accurate.

Discontinuous coarsening and the formation of equiaxed け grains at the grain boundaries were often observed in the aged condition (see arrows in Fig. 2).
thicken and join together while growing into adjacent grains.
The size and number of these interfacial precipitates increased with both aging time and W content as shown in Fig. 3 (see white phase in the BSE-SEM images).The amount of W had a more pronounced effect on the formation of the precipitates.
If an easy grain boundary path was not available, the grain itself was fractured either along a lamellar interface or in an intra-granular fashion.
Aging also led to the formation of interfacial precipitates, with their size and number increasing with W content and aging time.