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Unmelted Al2O3-ZrO2/Y2O3 nanoparticles have similar spherical grains as the original nanometer powder of ZrO2.
The grain boundary has a scattering effect on phonons, and the photon is easily scattered by small pores and cracks.
Thus, increasing the number of microcracks, porosity and grain boundary is very important to reduce thermal conductivity and improve the heat insulation effect of coating [14, 15].
Nanostructures area formed with unmelted nano powders increased the number of coating grain boundary and nanoscale tiny pore, which strengthened the scattering of the coating to the photons, and decreased the thermal conductivity of the coating.
Therefore, when the thickness of the coating increases, the number of the grain boundary, pore and the inner layer structure of the coating will also increase, which will further improve the insulation performance of the coating.

The primary α plates form predominantly on β grain boundaries, whereas the bainitic α plates nucleate both at grain boundaries and intragranularly.
These α plates are generally irregularly shaped plates, which nucleate predominantly at the prior β grain boundaries.
The bainitic α plates are relatively perfect thin plates, which nucleate both at grain boundaries and intragranularly.
It is seen that the bainitic α plates have nucleated both at former β grain boundaries and intragranularly.
Based on a number of micrographs it is found that the thickness of bainitic α plates is in the range of 0.2 - 1 μm.

Based on a large number of experiments, Mn should selest in the range of 1.5%～3.0%
(2)In order to give full play to the strengthening, toughness of the phase boundary, the grain boundary and sub-grain boundary of microstructure, the precipitation of carbon in steel from the supercooled A phase cannot be low intensity proeutectoid F, and should be high strength, high toughness of BF, and the final microstructure should be mechanical mixture (BF+A).
Supercooled A of steel should carry on the phase transition in the middle and lower temperature period with medium temperature on bainite formation and should add trace elements V, Nb which could refine the grain size .
The three ball grind out a number of plane on the grinding wheel respectively, the values of hardness are shown in table 2.
The characteristics of the granular bainite is a number of granular island which are a carbon-rich austenite at high temperature zone inside the large block or acicular ferrite.

Therefore, much attention has been increasingly paid on semisolid metal (SSM) processing, which is characterized by a number of advantages, such as low porosity, heat treatability, consistency and soundness of mechanical properties, the ability to make complex component shapes and longer die life [2].
It can be seen from the figures that, in the case of HPDC, when pouring temperature is at 660°C, microstructures of test samples are made of coarse and dendritic grains; when pouring temperature at 630°C is near to the alloy liquidus, the microstructures are similar to that of commonly low superheat pouring case, its grain morphology is fine, rosette-like but not uniform.
When processed by the modified MSCP, a uniformly fine, globular Si grains can be obtained as shown in Fig. 4(b), and its mean grain size of primary phase Si is less than 30µm.
(a) (b) In the conventional casting processes, heterogeneous nucleation takes place from the mould wall, and then columnar grains increase progressively as solidification proceeds, since those grains which have a preferred growth direction oriented near the heat flow direction tend to "crowd out" less favorably oriented grains [9], thus solidification structures are not homogeneous.
It not only increases the amount of potential nucleation agents, but also disperses the cluster of potential nucleation agents, giving rise to an increased number of potential nucleation sites.

The numbers in the graph were obtained using EBSD analysis and the details are presented in [5].
In the sample heated at rate of 60 K/s, mostly sub-grains are formed in the formerly deformed ferrite grains, and the cementite is not completely dissolved at 775 ºC. 3 K/s 60 K/s 750 ºC 775 ºC Fig. 2.
The ferrite grain size is similar, but the appearance of ferrite grains is changed.
At 780 °C annealing temperature the ferrite appear clearly delimited from each other and the martensite is mainly dispersed at the grain boundaries, whereas at 840°C annealing temperature boundaries between ferrite grains are no longer so keen to identify and martensite and bainite is embedded in these ferrite grains.
[5] Property oriented design of hard constituent hardness and morphology in continuously annealed/galvanized DP sheets – VADPSheets – Contract Number: RFSR-CT-2011-00014

Particular attention is paid to the form factor of solid grains.
Essential requirements for thixoforming materials with h - viscosity, k - constant, g - shear velocity, n - Oswald-de Waele exponent; dm - mean grain diameter, f - forming factor, A - grain surface area, U - circumference of a grain, SSS - the grain boundary surface area between the solid phase, i.e. the surface area between the cohering grains not separated melt, SSL - phase boundary surface area between solid phase and melt, dT - melt range, f(c, T, p) - function of (alloying element content, rate of cooling, pressure), fS - proportion of solid material, TM - melt temperature of a component; TL - liquidus temperature; p - exponent defined by the phase state equilibria.
The increase in the liquid phase fraction, calculated based on Scheil equation for a number of aluminum alloys, is shown in Fig. 4a and Fig. 4b.
Thus, according to the initial estimate determined by the factors Fα and Dm, the billets obtained by casting using a water-cooled slope represent a product of the required quality in terms of grain size and morphological features, suitable for processing by thixotropic forming methods.
The number of structural components including the amount of structurally free liquids required for high-quality forming of parts from alloys that are compositionally close to eutectic, may be provided through the use of the conditions of thixobillet formation that are far from equilibrium only as the solid phase at the stage of equilibrium solidification of a thixobillet reaches ≈ 50 %.

It can be seen that grains and carbide fragments are elongated along the stress direction in all the samples, while the deformation of microstructure increases with creep time.
Some viewed that creep holes nucleate by grain boundary slide, while other attributed the nucleation to the separation of second phase particles from matrix.
In this paper, band of cavities forms along the grain boundaries after creep for 152.5h, in the condition of 450oC /320MPa(Fig.5c).
The shedding of coarsened carbide at sliding grain boundaries during creep promotes the nucleation of cavities.
It can be inferred that the temperature of 450oC is not high enough to stimulate large number of dislocation climbing for non-quenched and tempered steel.

The overall average grain size was about 7 µm.
Close observation indicated that a very small number of residual nanometre-sized pores were present at some grain boundaries.
Although this enhanced level of oxidation might not have helped with the bonding process, the oxide particles, which were of nanometres in size and distributed at grain boundaries, may have increased the thermal stability by preventing grain growth.
Grain boundary strengthening was believed to be responsible for the increase.
The material consolidated from the micro Al particles possessed elongated grains with an average grain size of ~7 µm, and that from the nano Al particles displayed equiaxed grains with an average grain size of ~125 nm.

p...1j,iH j jij i o =γ=τ ∑ && (2) a sat i o o ijij 1hqH ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ τ τ −= (3) where p is the total number of slip systems in Eq. 2, and ijHis a (n×n) hardening matrix.
Adding up over all systems and over all grains, we can obtain the accumulated twin fraction, emod,acc V in the grain for the particular twin mode
After uniaxial compression to true train, ε=0.04, the c-axes of many grains are aligned with the RD.
As true strain increases to ε=0.1, the c-axes of nearly all grains are aligned with the RD.
As a result, the model sacrifices the character of the anisotropic interaction between grain and matrix [12].

The highly energetic compressive impacts create a large number of clean interfaces where inter-diffusion of the associated atoms starts and eventually result in a homogeneous phase.
Extremely large grains were observed in the samples with 2.0 mass% Ag.
The fracture surface of coarse grains shows faceting appearance.
In addition to the large grains with an average size of about 400 nm, many small grains, less than 100 nm diameter, were identified.
These small grains are preferably present at the boundaries of large grains.