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On the other hand, the compound has been fabricated as a composite material containing a secondary phase such as Al2O3, Ti2AlC and Ti5Si3 [6.7], which improve the ductility and the toughness at room temperature by reducing grain size and lamellar spacing.
Ti(wt. %) Al(wt. %) Cr2O3(wt. %) Theoretical target Al2O3 content (wt. %) A 0* 64 36 0 0 A 1 62.47 36.27 1.49 1.00 A 3 59.55 36.74 4.47 3.00 A 5 56.63 37.21 7.45 5.00 A7 53.71 37.68 10.43 7.00 A12 46.40 38.85 17.89 12.00 A15 42.02 39.56 22.36 15.00 *AX refers to the sample number, and X is the targeted weight per cent of Al2O3 phase Results and Discussion Fig.1.
It is evident that the monolithic TiAl sample offers a large grain sized structure (Fig.2(a) and 2(d)), while the matrix structure is refined obviously when appropriate amount of Cr2O3 was added (Fig.2(b) and 2(e)).
According to the Hall-Petch theory [10], the fine precipitated Al2O3 particles and fine grain sized matrix structure play an important role to increase the strength.
The in situ formed Al2O3 particles tend to disperse on the grain boundaries, and formed a discontinuous network.

The only differences in Fig. 1 is that the aluminum mainly crystallizes in α phase and the grain size is small.
Figure 1 1050A pure aluminum parent metal ×500 Figure 2 HS311 fusion zone ×500 Figure 3 SAL-2 fusion zone ×500 Figure 4 1050A leftover material Figure 5 Homemade welding wire fusion zone ×500 fusion zone ×500 Fusion line in figure 2 is obvious, in which the grains show bigger size and a large number of pores and cracks are also observed.
Weld grain size is raised obviously in figure 3, and organization is not uniform, which mainly results from the lack of fine grains element in the formula, as well as segregation due to the high coefficient of thermal conductivity and faster cooling rate.
Figure 4 and figure 5 both show small grain sizes, and their difference is that there are defects such as inclusions, porosity in fusion zone by 1050A leftover material in figure 4.

Crystals of GF/PLA120s increase in number than those of GF/PLA0s.
For dPLA resin, hydrolysis accelerator is considered to play as crystal nuclei and resulting the smaller crystal grain size.
As the crystal grains are small, the grain boundaries are present more.
Fig.5 Crystal grain of GF/PLA. 20mm 20mm (d) GF/dPLA120s.
Fig.6 Crystal grain of GF/dPLA.

A huge number of cracks may cause serious defects and faults.
This condition is associated with high concentrations of hydrates, which are caused by the mineral grains (cement, sand, fine-grained component).
From this point onwards then the hydration is caused by grains in turn are pushed apart (expansion).
Standard concrete mixtures under normal laboratory conditions do have a shrinkage around approximately 0.7 mm / m, while fine-grained or improper concrete mixtures have abnormally high values at around 2.5 mm / m.

Introduction Extensive research has been done and a great number of papers have been published on the investigation of the adverse effect of natural aging (n.a.) on the resulting strength and hardness of artificially aged 6xxx alloy extrusions.
Grain structure was observed with polarized light illumination after Barker’s electrolytic etch.
The grain structure of the examined extrusions was fully recrystallized consisting of equiaxed, 85μm mean size grains.
Microstructural examination of “A0” and “B0” extrusions revealed no grain boundary precipitation of coherent phases.
Further heat treatment resulted in initiation of precipitation of non-coherent phases and coarsening (grain boundary Mg2Si precipitates).

In SiC reinforced solder, because of the effect of SiC nano-particles surface adsorption, the grain size of Ag3Sn and β-Sn was significantly refined in the composite solders, its micro-hardness increased by 30%~44% than matrix solder.
During the solidification process, because Sn crystallized around Ce, it may hamper the growth of IMC, such as Cu6Sn5 and Ag3Sn etc, to reach the purpose of the grains refinement.
Some research shows, POSS particles may pin in the grain boundary of alloy, so as to enhance the heat mechanical properties of solder, to improve the high temperature stability of the welding joint, to extend service life of solder.
The added and high melting point Particles can refine grain, this is similar to the microstructure of MMCs, these enhanced particles pin on grain boundaries and limit the motion of dislocations, and then, to hinder the grain growth, so that the original size of grain can be maintained in the long period.
On the another hand of sealing ability, although the reinforcement appears in solid state in the course of soldering, due to its small size, they can form a micro-capillary in the system of solid-liquid coexistence, and thus will not affect the sealing ability of liquid solder on the condition of right choices for the type and number of particles.

Tab.1 The parameters of graphene Sample Size/um Thickness/nm Number of layers Specific surface area/ m2·g-1 Graphene 10-20 3-10 3-4 650 Characterizations 2024Al powder and the mixed powder were analyzed by scanning electron microscopy (SEM; MIMA3, TESCAN) coupled by energy dispersive X-ray spectroscopy (EDS).
From the average grain size of the composite, it revealed that the addition of nano copper modified graphene could refine the grain size of the composite matrix alloy.
Graphene inhibits the grain growth in the aluminum matrix by restricting the small-angle grain boundary fusion, so that the finer grain microstructure could be obtained.
Mechanical behavior and strengthening mechanisms in ultrafine grain precipitation-strengthened aluminum alloy.
Effect of grain refinement on mechanical properties and sliding wear resistance of extruded Sc-free 7042 aluminum alloy[J].

The hard to be recovered gold mainly exists in leaching residue of flotation concentrate by means of three states listed as follows. 1 The gold exists in organic-carbon-bearing minerals characterized by carbon black grain, micro-fine grain size, and the gold content accounts for about 9% in the total amount of leaching residue. 2 The micro-fine grain gold exists among pyrite, copper pyrites and gangue mineral adherent, gangue minerals, the gold content accounts for about 14% in the total amount of leaching residue of flotation concentrate. 3 The micro-fine grain gold exists in pyrite, copper pyrites, and the gold content accounts for about 75% in the total amount of leaching residue of flotation concentrate.
When the velocity of ore pulp is relatively low at about 20mm/s, and the flowing film is very thin at around 2mm, the lower limit of recovery grain size reaches 5μm.
Factors influencing the Separation effect Influence exerted by the property of minerals In case the grain size number in ore feed is relatively wide; the influence on separation indexes is not great.
Expected economic and technical indexes have been obtained in recovering pyrite and other metallic minerals from the leaching residue of flotation concentrate in Tuanjiegou Gold Ore. 2 Multi-layer automatic plain chute can be applied to discriminate tungsten and tin ores, comprehensive recovery of iron, zinc, copper and other associated metal elements, recovery of valuable metallic minerals from refractory ores, discriminate refractory ores and recover valuable metallic minerals from middling products with combination of other processes. 3 In case of treating relatively coarse grained raw materials, the thickness of water layer should be 10~2mm; in case of treating fine-grained raw materials, the thickness of water layer should be below 2mm, the lower limit of grain size for recovered metal should be 5μm.
Multi-layer automatic plain chute possess excellent performance in discriminating and recovering metallic minerals from fine-grained materials. 4 In case the volume of lean ore or ore pulp is large, it is necessary to use pinched chute to enrich the selected ore pulp at first, and then conduct gravity test after ore concentrate is fed. 5 No strict limitation for the roughness of surface bed of multi-layer automatic plain chute.

At execution of examinations by traditional methods optimisation of prescribed and technology factors is bound to a great number of experiences.
The primal problem of production engineering in this phase consists in the uniform allocation of all formulation constituents, enveloping of grains of gravels solid, uniform on width for grains of one size film of bitumen and shaping of coagulative contacts on mineral grains.
At mixing of mineral materials with bitumen processes of wetting by bitumen of a surface of mineral grains, physical and a chemical adsorption of builders of bitumen a surface of mineral grains, filterings of low molecular weight builders of bitumen in pores of mineral materials and bitumen structuring at the molecular interacting with a surface of mineral grains [1, 2, 6, 7] flow past.
At a mixing rise of the temperature of the asphaltic concrete mixes requirements of wetting of grains of a mineral material bitumen improve, and its optimal charge is downgraded.
It is installed that at a rise of temperature of mixing of a road concrete mix requirements of wetting of grains of a mineral material bitumen improve and its optimal charge is downgraded.

According to experimental method, a number of hard particles (ceramic beads) fill between the electrodes and are propelled by mandrel’s rotating movement to allow continuous impinging and grinding to the cathode surface, as an effort to instantaneously eliminate boundary effect that is caused by uneven current distribution.
However, the instability of grain crystallization and electric-field distribution under high current density often lead to the deterioration of deposition uniformity and quality, restricting further development of this technology.
Hard grinding grains were ceramic beads with average diameter 1mm, repeatedly washing with distilled water before use, in order to remove impurities.
Experimental Result and Analysis Fig. 2 (a) shows a simple pattern’s morphology under positive pulse current for 20 min in the absent of hard grinding grains.