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crack extension ∆Lvir under constant stress and by using the standard definition µ= - dF/dn, where n is the number of the solid atoms which should be removed from the tip for having the extension ∆Lvir [2,17].
Crack initiation and propagation from the grain boundary grooves .
II-6 Crack profile and grain boundary 'swelling' by DCM.
GALOP mechanism of LME: grain boundary grooving under stress σ [3].
Gust, Fundamentals of Grain and Interphase Boundary Diffusion, Ziegler Press, 1989 21.

As seen from Fig. 3(a), by heating the alloy at 700℃ for 2 h, an obvious polycrystalline structure with a winding interface or grain boundary (GB) can be observed, which is believed to be the result of the evidently coarsening or spheroidizing of the as-cast dendrites, and the average grain size is about 15 to 30 μm.
Subsequently, Fig. 2(b) exhibits a novel morphology of the alloy as heated at 900℃, wherein a large number of needle-like precipitates with a size of several tens to hundreds nanometers are intensively distributed around the GB or even in the grain matrix.
Fig. 2(d) is the magnification of Fig. 2(c), and the average grain size is about 50 - 100 μm.
In addition, large numbers of nanoparticles with a diameter of 100 nm are homogeneously distributed in the dendrites.
Similar to the Al1.0 alloy at the same state, this alloy also exhibits a completely homogeneous matrix with larger numbers of worm-like precipitations with sizes of 300 - 500 nm as shown in the inset of Fig. 5(d).

It is vital to know how to correctly use this data to make an accurate evaluation of this foundation soil layer, therefore, to improve the quality of the geotechnical engineering investigation. 4 Penetration Test 4.1 The Factors to Influence the Accuracy of Penetration Test 4.1.1 The Influence of Foundation Soil It has been found that, the particle composition of the gravel soil may have significant impact on the penetration blow count, which is shown that, when the particle size of the framework grain is big, as well as the discreteness of penetration blow count; On the contrary, when the particle size of the framework grain is small, the discreteness of penetration blow count may lower.
Besides, the compactness of the gravel soil, the fillings compositions, the weathering degree of the framework grain may have the directly influence on the penetration blow count.
As the Tab.2 shown: Tab. 2 The statistical results of the hammering number () for heavy cone dynamic penetration test Names and Numbers of Soil and Rock Statistical Number Average Value Standard Deviation Coefficient of Variation Correction Coefficient Standard Value Breccia③ 514 9.30 2.28 0.244 0.982 9.13 Breccia④ 560 12.50 1.978 0.158 0.989 12.36 By the statistical data above, we can have the important assessment to the foundation soil’s property in the following: The layer③ of the area: mainly consist of breccia and spread widely in the area, it is one of the major foundation soil layers in this geotechnical exploration.
However, there also many factors to influence the penetration blow count, including the particle composition of foundation soil, compactness, component of filler, weathering degree of framework grain.
Especially when the particle size of the framework grain is relative big, so as well as the discreteness of the experimental data, and it may appear more outliers.

When the samples cool from high temperature, a large number of transgranular second-spinel separates out resulting in cubical expansion and more cracks formed. [11] Fig.4 SEM photographs of sample 3 under different magnification times Physical Properties.
On the basis of Griffith micro-cracks theory, the breaking strength of the materials does not depend on the number but on the size of the cracks (the most dangerous size determines the breaking strength).
The cement clinkers do not only react at the surface of bricks but also permeate in slotted section of aggregate grains.
By analyzing the white area (A) between aggregate grains, there are a number of Ca, Si, Al and Fe, but only a little Fe is found in the aggregate grains (B).
It shows that the reaction between FeAl2O4 and cement clinker can produce C2F and C4AF, and except that, the Fe can separate out from magnesia and react with the cement clinker located on the surface or in the intercrystal porosity of aggregate grains.

To do so, we employed a number of characterization techniques: XRD, Raman spectroscopy, SEM, AFM and UV-Vis spectroscopy.
This tendency in grain sizes observed by SEM is consistent with that of crystallite sizes obtained from XRD data analysis.
However, it should also be noted that the grain size is larger than crystallite size since an individual grain is generally composed of several crystallites [48].
To have an estimation of the refractive index and its trend with substrate temperature, we have employed the methodology that has been applied by Duffy [56, 57] to a number of simple oxides such as SiO2, BaO, CaO, MgO and TiO2.
SEM and AFM images have revealed that the TiO2 films deposited at room temperature displays homogeneous and smooth surfaces consisting of small grain size particles whereas increasing the substrate temperature results in denser films with larger grain sizes and rougher surfaces.

Influence of Compressive Torsion Processing Temperature on Microstructure Refinement and Property of Aluminum alloy Shotaro Tahara 1,a , Yuji Kume 2,b , Makoto Kobashi2,c , Naoyuki Kanetake 2,d 1 Graduate School of Engineering, Nagoya University, JAPAN 2 Department of Materials Science and Engineering, Nagoya University, JAPAN a h062131m@mbox.nagoya-u.ac.jp, bkume@numse.nagoya-u.ac.jp, ckobashi@numse.nagoya-u.ac.jp, dkanetake@numse.nagoya-u.ac.jp Keywords: Hypereutectic Al-Si alloy, Severe Plastic Deformation, Grain refinement, Compressive Torsion Processing Abstract.
For getting higher ductility without degrading superior properties, it is necessary to evolve microstructure including refinement of Si phase as well as aluminum matrix grain.
Four test pieces were machined and numbered as (i) to (iv) sequentially from the center to the periphery as shown in Fig.2.
Refinement of aluminum matrix grain would be also related, but detailed consideration of the relation to processing temperature has remained a challenge for the future.

Attempts to use first principia methods to understand light absorption in the matter have been made by a number of authors.
Recent thermodynamics calculations allow evaluating the Ms temperature for a number of alloys, including some steels [[] M.
During laser heating a-grains quickly transform to b by sharing transformation.
During welding, equiaxed alpha grains form at the melted zone and some twining could be found.
During heating some precipitates may be solubilized and, depending on cooling rate, the aluminum grains become a homogeneous face centered cubic a-grain.

Mo can obviously improve the wetting ability of liquid metal to hard phase and can limit the grain's growth of carbide phase in sintering.
According to Hall-Petch's formula, the relation between the material's yielding stress (or hardness) and its grain size is [8]: n a dKC+=σσ （1） where,σ is 0.2% yielding stress; K Ⅱ is constant; σa is moving force of a dislocation to overcome lattice frictional force; d is average diameter of grains and n is index number of grain size.
As Hall-Petch formula expresses, the intensity and hardness of nano-structure material is higher because of the reduction of grain size.
The above equation shows that the falling extent of melting point is opposite with the grain diameter.
When the grain size decreases, its melting temperature will drop.

The stress analysis of bridge crossings is complicated by the great number of butt-welded and T-joints.
As a result, the intensive plastic deformation occurs in zone 1 providing grain fragmentation and in situ heat of the metal surface with its subsequent cooling.
The multiple recurrent process of plastic deformation is accompanied by grain fragmentation.
As far as the distance from surface grows (zone 2), the plastic deformation decreases as well as the grain fragmentation (Fig. 4 a) due to the decrease of heat temperature and increase of ultrasonic peening.
In zone 3 shown in Figure 4 a, an insignificant grain deformation is observed while the value of microhardness decreases down to that of untreated steel (Fig. 4 b).

The low magnified SEM image (Fig. 5a) represents that the MoO3 samples are composed of large number of nanorods.
The single semi circle arc (Fig. 8a) observed is corresponding to grain and grain boundary effects implying the identical time constant.
The arcs are found to be highly depressed in the case of 175 °C and 250 °C due to the distribution of relaxation times which is a serious combintation of consstant phase elements (CPE) parallel with grain and grain boundary resistance [8].
Complex impedance spectra shows two depressed semi-circles reveals the presence of grain and grain boundary contributions on the charge transport process.
The grain and grain boundary resistance decrease with increasing the temperature and confirms the negative temperature co-efficient of resistance of h-MoO3.