Search results

As a consequence, stress fracturing all along mineral grain boundaries in a gangue matrix, selective oxidation, or reduction of the valuable minerals of an ore may well be passing the proper gas through the ore during the microwave irradiation.
Restricted mineral-grain heating tends to cause microcracking within the material, which leads to a more efficient liberation upon grinding.
photomicrographs confirm that fractures along grain boundaries and throughout the gangue matrix are described as a related approach [13].
Advanced energy levels in the mineral grains, with longer heating times or amplified power levels, is also able to lead to phase, and still chemical changes in the mineral.
A number of academic institutions are conducting wide-ranging researches on the subject matter.

Vanadium dioxide (VO2), a traditional oxide as MIT material, has merits of less compositional number of two and relatively low transition temperature around 68°C [3,4].
In Fig. 2(a), oriented growth aspects of V3O7 crystal grains with (110) surfaces were seen.
On the other hand, we see crystal grains around 1 μm with a part of crystal grain boundaries in Fig. 2(b).
Crystal grain sizes and the presence of grain boundaries are suggested to dominate transition characteristics [8].

Each grain is assumed to deform with the same macroscopic strain and the resulting stress in each grain is averaged over the distribution of grains in the polycrystal to give the macroscopic stress.
The grains are characterized by their orientations with respect to the material symmetry axes which are obtained via X-ray or electron back-scattered diffraction techniques.
The number of grains considered in the calculations was 560 .

The highest dislocation density and the lowest grain size were observed in EN AW 7075 alloy which was treated by T3 processing.
Numbers of cycles to final rupture of materials are summarized in Table 3.
Fine grained morphology was observed in the composite EN AW 6061.
The composite EN AW 6061 had highly fractal fracture with fine grained morphology
- The grain size and dislocation density of aluminum alloys were observed by TEM and the observation proved that the mechanical properties (especially YS/UTS) of alloys are the most dependent on the treatment.

The most common crack locations in cladding layer Through the study of a large number of data, it shows that the cracking phenomenon often occurs in the arc cladding process.
The interface impurity happens each columnar grain between adjacent and produces aggregation and weak area so the cracking tendency is enlarged.
At the same time, it also can purify the grain boundary and improve the strength and toughness of the interface.
This experiment proves that in the conditions of strict control of arc power density, shortening the cladding material in the arc of the retention time, rare earth elements can pass into the cladding layer to powder cladding, and they can refine grains and reduce the cracking tendency.
It also shows the growth of columnar crystal along the direction of heat flow on the interface of cladding layer and the substrate and grain refinement improves the strength and toughness and decreases brittleness and reduces crack tendency of cladding layer.

Materials consist of the a-Si3N4 grains (equiaxial grains) and b hexagonal silicon nitride grains.
The incorporation of the graphene platelets supressed the phase transformation from a®b and caused the higher amount of the equiaxial grains for composite with higher amount of the graphene platelets.
The incorporation of secondary phases, such as carbon-nanostructures, into a ceramic matrix generally inhibits the sintering driving force [6], which leads to a lower grain size in comparison with the monolithic material at higher temperatures, or to a suppression of α to β transformation of silicon nitride at lower temperatures [7].
Pan, Measurements of mechanical properties and number of layers of graphene from nano-indentation, Diamond and Related Materials, 24 (2012) 1–5.

However, the mechanically-alloyed nanostructured powders should be densified without any grain growth during sintering process.
Journal Title and Volume Number (to be inserted by the publisher) XRD analysis for sintered bodies (Fig. 3(a)) revealed that Ni3Al coexists as the second phase together with NiAl.
The grain size determined by X-ray line broadening method was approximately 80 nm.
Fine grain size of mechanically alloyed NiAl powder compact resulted in excellent mechanical properties.
Grain size observed by TEM ranged in 100 nm scale

Bismuth-based materials exist as the candidates and their properties were reported.1, 2) However, there are still problems such as the increase in the number of composition elements, and safety of bismuth.
In each composition, the grain/grain-boundary structure was confirmed, and the average grain size was estimated to be about 40 nm though the grain sizes were slightly different.
The one is condensation peculiar to the small grains obtained from alkoxide materials, and the other is unusual growth by flowing oxygen gas using a RTA furnace.

Right before the thrust decay, the temporary thrust raising is due to grains fragmentation prior to burn-out.
The solid propellant consists of twelve tubular grains, arranged in a triple-triangular package, more compact than the hexagonal mount.
Fig. 2: Thrust history A neighboring configuration, four millimeters more compact in radius only, produces a slightly unstable position of the grains.
Therefore the decreasing mass of the solid grains remains bound to the aft grid up to the end of combustion, where the propellant mass is concentrated regarding the mass center.
In the present case with a solid propellant charge comprising of twelve cartridges, the variance of the size and burning duration on individual grains is considerably mediated by their high number.

Utilization of stereological metallography for short fibre orientation in plastic matrix is very similar to its utilization for estimation of grain boundaries orientation in polycrystalline alloys cased by plastic deformation.
Utilization of stereological metallography for short fibre orientation in plastic matrix is very similar to its utilization for estimation of grain boundaries orientation in polycrystalline alloys caused by plastic deformation [4].
The anisotropic microstructure is decomposed into isotropic, planar or linear oriented components using stereology methods.The main three components of the second-order orientation tensor using stereology can be calculated as follows: aii=PAiPAx+PAy+PAz (5) where i= x, y, z PA is number of cross-sections between test plane and fibres [-] Ai is investigated area [mm2] PAiis number of cross-sections between test plane and fibres per unit of the test area [mm-2] Measured and calculated results in each analysed placesare in table 1.
However, measurement of number of intersections is very simple in comparison with measurement of intersection dimensions, which required an image analyser [6].
The utilization of stereological metallography allows very simple and effective experimental estimation of short glass fibre orientation by measuring number of cross-section between test plane and fibres in various places of injection moulding parts.