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Since the surface free energy is considered to be a driving force in the sintering process, a number of sintering models have been researched for the initial stage of sintering and the resulting equations can be summarized as follows[15]
(4) Where K1 and w are constant, D is the diffusivity, γs is the surface energy, Ω is the atomic volume, G is the particle or grain size, k is the Boltzmann's constant, T is temperature, t is sintering time and m is a constant depending on the diffusion path.
Kang (2005) Sintering: Densification, Grain Growth & Microstructure, Elsevier Butterworth- Heinemann, Burlington.

The numbers indicate the minimum yield strength in ksi.
Fig. 7 illustrates the weld root at higher magnification where it appears grain growth has occurred across this lazy-S feature.
Micrograph illustrating grain growth across the root flaw.

Marked progress was due by, principally, high level and/or unique combination of a number of structure-related physical properties (principally magnetic and mechanical) of alloys in disordered state [3-5].
The annealing purpose is the obtaining nanocrystalline state to all product volume without transition into temperature range in which recrystallization process leads to structure with larger grains having significantly worse properties, is implemented.
It can be assumed, that the phases separation on grain boundary are process taking priority of one fast growth at recrystallization.

However, this method has a number of significant drawbacks, since the high-temperature energy source and the different deformation capacity of the parts are the cause of considerable post-welding stresses.
A significant disadvantage of this technology, in our opinion, is the preservation of a relatively wide HAZ, which includes an overheating section with large grain structure with low toughness.
We used these technologies because: - the use of forced cooling during welding allows us to increase the cooling rate, and we are able to significantly reduce the grain size, reduce the HAZ and increase the strength characteristics of the welded joint and its toughness; - ultrasonic shock oscillations have a complex effect on the welded joint, reducing stress load concentrations in the welded joint, creating a reinforcing layer on the surface being treated with increased resistance to cracking, etc.

Introduction Concrete is classified as a composite material since it is composed of a number of aggregates, water, and other admixtures such as metal that serve as reinforcement for the concrete.
Despite their irregular grain sizes, grains are easily evident in all of the samples' microstructures, this observation is similar to the previous research done [9-11].

By repeating this process a number of times a solid 3D object of intended shape is fabricated.
At slow and fast cooling rates, the β-phase transforms to the acicular α-phase and metastable hexagonal α’-martensite and some residual β at grain boundaries, respectively.
Owing to the high temperature gradients that happen during the SLM process, the microstructure of the as-built SLM samples comprises of a martensitic α′-phase within prior β grains that are mostly aligned with the building direction.

Nowadays magnetic nanoparticles (MNps) are used in increasing number of applications including biomedical ones due to the possibility of MNps injection and accumulation in the target tissue [1].
Size of grains is varying in a wide range from 5 nm for the sample with 60% of Zn up to 25 nm for 20% Zn sample (Fig. 1).
As the result, all the samples showed predicted spinel structure with characteristic grain size 6.5 nm that is in the confinement with TEM measurements.

Ultrasonic liquid processing depends on a number of parameters, such as amplitude, pressure, temperature, and viscosity.
Katgerman, Influence of ultrasonic melt treatment on the formation of primary intermetallics and related grain refinement in aluminum alloys, J.
Ma, Ultrasonic grain refinement of magnesium and its alloys, InTec, Available from: (2011).

However, Wakai et al. have found that the ceramics indicate superplastic deformation at an elevated temperature by grain refinement of its microstructure [2].
Acknowledgement This study was supported by JSPS KAKENHI Grant-in-Aid for Scientific Research (C) Grant number 24560888.
Manabe, Grain Refinement by Combined ECAE/Extrusion and Dieless Drawing Processes for AZ31 Magnesium Alloy Tubes, Mater.

Basic Characteristics of The Chang2 Reserviors Study area Chang 2 reservoir sandstones basis Fork (1968) sandstone classification division, According to some observations and thin section analysis of core results and previous research results, Triassic oil exploration Zhidan oilfield Zhifang area Chang 2 member reservior in the lithology is mainly light gray-fine-grained feldspathic sandstone, light gray-brown in-fine-grained detritus arkose(Figure 2), the sandstone clastic composition as including feldspar, quartz, debris and clastic mica and argillaceous rock detritus, gushing rock detritus, metamorphic detritus, etc., Chang 2 reservoir is mainly distributed in the porosity of 8.0% to 18%, and Chang2 reservoir permeability was 16.43 × 10-3μm2, Chang2 reservoir porosity and permeability with a good positive correlation between the performance of infiltration rate with the increase of porosity；According to analysis results and so on ore thin slice, casting sheet and scanning electron microscope
Model grid are orthogonal grid system, grid step of 100 × 100m, the plane was divided into 121 × 119 grids, the vertical steps of 1.6 m, was divided into 55 micro-layer, modeling The total cell number was 121 × 119 × 20 = 286630.