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And compared with squeeze casting process, the globular shape grain size is smaller than dendritic structure.
And the grain size of two processes were measured by the “Line Interception Method”.
It was measured that grain size of SSM die castings is 103.8±5.1μm, and the grain size of squeeze castings is 137.2±7.9μm.
By means of chilling action of the low temperature pouring process, a large number of primary solid phases are formed through to refine the grains.
Grain size effects on the mechanical properties of some squeeze cast light alloys[J].

In the as cast condition, the alloy possesses coarse, equiaxed β grains and Transmission Electron Microscopy(TEM) observations showed the ω phase is also present in this condition.
Direct ageing at 450°C for 4 hours leads to the formation of a large number of fine scale α phase precipitates.
Fig.2a shows a typical cast microstructure with coarse single phase β grains.
The ω phase may provide sites for the nucleation of the α phase enabling the formation of a large number of fine α laths uniformly dispersed throughout the β matrix.
Conclusions The as cast Ti-25Nb-3Zr-3Mo-2Sn alloy exhibits a structure comprised of coarse equiaxed β grains in conjunction with extremely fine, coherent precipitates of the athermal ω phase.

Significant grain refinement with grain size of ~100 nm was achieved even after 1/4 of HPT rotation.
Other preferential nucleation sites for α-phase are β/β grain boundaries and dislocations [10].
Ultrafine grained structure with nanometer sized grains is observable already after N = 1/4 HPT turns.
The microstructure of the Ti15Mo alloy after higher number of HPT rotations (N > 1/4) exhibits more deformed structure as it was reported in our previous work [14].
The individual grains of the UFG Ti15Mo alloy cannot be distinguished due to the overlapping grains through the thickness of the foil.

Basic research on SSM has been put into operation and a number of SSM techniques have been widely applied in industry.
The solid fraction of semi-solid 1Cr18Ni9T is more (fs=60%), the shape of solid phase-grain is better and the size of grain is smaller than that of 60Si2Mn.
It is well known that the strength and the ductility of a metallic material increase as the crystal grain becomes finer.
There are a number of parameters that affect the flow behavior of semi-solid slurries such as viscosity, deformation ratio, and shape of roller and roll velocity and deformation temperature, etc.
The liquid phases and solid phases are detached and a number of liquid phases flow to the edge during deformation (see Fig.3 (a)).

Results show that wall thickness 0.18~0.23mm, cell number (1/in2) 316~339, clear cross section (%) 69~74, specific surface Sv (sq m/cu dm) 2.35~2.52; specific heat capacity Cp(J/g.K) 0.60~0.70, heat conductivity k (W/m.K) 6.52~6.78.
SEM/XRD analysis shows that a large number of oxides formed on the surface of sintered honeycombs during sintering, such as Fe2Cr204, Fe2Si04, Al2O3.These oxides connect together to form film on surface of sintered honeycombs.
It is obvious that raw small powder particles bind together to become grains at sintering time from 30 min to 60min,and with the extension of sintering time, grains connect and grow up (Fig.3b, Fig.3c).
Fig.1 The structure of extruded honeycombs Fig.2 The effect of sintering time on the volume expansion and apparent density of sintered honeycombs (a) (b) (c) Fig.3 The SEM photographs of FeCrAl sintering honeycomb at different time (a) sintering at 1200°C, 30min ; (b) sintering at 1200°C, 60min; (c) sintering at 1200°C, 90min Fig.4 XRD pattern of Fe-Cr-Al sintering honeycomb Table.1 Structure parameters of sintered metal honeycombs Material Cell Size (mm) Wall thickness (mm) Cell number (1/in2) Clear cross section (%) Specific surface (sq m/cu dm) FeCrAl honeycombs 1.1~1.3 0.18~0.23 316~339 69~74 2.35~2.52 Ceramics honeycombs 1 0.2 400 67 2.4 Table 2 Physical characteristics of FeCrAl and ceramic honeycombs Material Density (g/cm3) Spec. heat capacity (J/g.K) Heat conductivity coefficient (W/m.K) 25°C ~50°C FeCrAl honeycombs 1.1~1.3 0.6~0.7 6.52~6.78 Ceramics honeycombs 0.6~0.7 1.05 0.8~1.0 XRD analysis from Fig.4 shows a large number
While sintering at 1200°C, the raw small powder particles bind together to become grains, the grains connect and grow up, with the extension of sintering time.

Severe plastic deformation and grain refinement were also induced by the process, and the average grain size of nano-structured regime was about 46 nm.
A large number of knife scar with about 100 μm wide and 60 μm deep were observed on the specimen surface.
A surface layer with high density dislocation and ultra fine crystal grain were formed after shot peening (as shown in Fig.2).
The diameter distribution scope of the crystalline grain was about 5~135 nm and the average diameter was about 46 nm.
(2) The shot peening process could reduce grain size and increase dislocation density in the surface of 30CrMnSiNi2A steel specimens.

,Ltd, State Key Laboratory of Vanadium and Titanium Resources Comprehensive Utilization, Panzhihua 617000, Sichuan, China jianglongkui2002@yahoo.com.cn Keywords: Copper slag; Magnetite; Oxidation Abstract: Large number of available resource is in the copper slag, which includes oxides of copper and oxides of iron.
Because minerals in copper slag embedded with each other and the grain of minerals in copper slag are very small, so it is very difficult to recover iron from the copper slag by means of traditional separation technology.
Based on the characteristics of copper slag, iron in copper slag can selectively be gathered to magnetite phase through the melted copper slag is processed, and the size of grain of magnetite grows up by adopting appropriate measure to control the reaction temperature.
Bases on the features of copper slag, oxidizes molten copper slag makes iron beneficiation to magnetite selectively in copper slag, and temperature control in proper range makes grain of magnetite grow up.

There are no precipitates observed in the Ag-free alloy after ageing for 0.5 hour, shown in Fig. 5(a), while a number of cellular discontinuous precipitates have formed along the grain boundaries in the AZ80+0.5Q alloy, as seen in Fig. 5(d).
The discontinuous precipitates grow perpendicularly the grain boundaries into the contiguous grains.
The number evolution of precipitates is corresponding to the change of hardness during ageing, the hardness of the aged alloys increased distinctly after ageing for 4h.
The discontinuous precipitates colonized all the grains in AZ80 alloy, while a relative smaller number of continuous precipitates exist in the AZ80+0.5Q alloy.
Generally, the discontinuous precipitates preferentially nucleate from the high-angle grain boundaries and grow into the neighboring grains as the cluster of lamellas.

The coating was typically characterized by micro pores and ball-shaped round grains distributed on the surface.
With increasing the treating current density, the pores became bigger and the ball-shaped round grains became more.
In addition, there are some ball-shaped round grains piled or distributed on the surface.
In addition, it can also be seen that when increasing the current densities, the diameters of the pores increased and the number of the ball-shaped grains also increased.
There were some micro pores and ball-shaped round grains distributed on the surface.

Among these methods, laser machining can offer a number of advantages; it can produce three-dimensional (3D) chip breakers, and a smoother, more consistent cutting edge finish.
The circles with diameter from 0.2 mm to 0.4 mm were all scanned 20 times, but the number of scans for the circles with diameter from 0.2mm to 0.01mm decreased gradually from 20 to just 1.
It can be seen from Fig. 4 that only the grain boundaries were ablated; the diamond grits were not ablated at all.
As a result, the thermal conductivity of the grain boundaries decreases significantly.
It has been found that only the grain boundaries were ablated without any damage to the diamond grits.