Search results

By increasing the magnification and decreasing the step size for EBSD data acquisition it is also possible to map the substructure within the deformed grains.
Fig. 5 shows the deformation substructure in two grains: the boundaries shown have a misorientation between 0.7 and 5º and the grains are separated by a high angle grain boundary of misorientation ≥15º.
The number and size of the precipitates in the steel sample were similar to those seen in the Fe-30wt%Ni, as expected from previous work [7].
- Fine strain-induced precipitates of similar size and number density have been observed via Moiré fringes in both alloys
Palmiere: Proc. 1st Joint Conf. on Recrystallisation & Grain Growth, ed.

The binary PbO-SrO phase diagram shows that the vapor pressure decreases when compared to the pure PbO one, so that the liquid phase in grain boundaries is preserved at high temperatures [9].
As consequence, the PZT grains are coarsened and the pore eliminated more efficiently due the higher mass transport [10].
Thus, it is possible infers that the profile variation is caused by extrinsic effects, such as differences in grain size or bulk porosity.
The crystalline phase identification showed the coexistence of two phases, associated to R3mR rhombohedral (ICSD card number #77585) and P4mm tetragonal (ICSD card number #90699).
The grain boundaries present some elastic coupling effect between domain wall and grain boundary, which can inhibit the domain wall motion.

A general approach, not restricted to a principal stress state and a limited number of � values, was suggested recently by Ligot et al. [8].
Elastic grain interaction In the case of a single-crystal like texture no assumptions with respect to elastic grain interaction are made.
The elastic grain interaction was modelled employing the Neerfeld-Hill and the Reuss grain interaction models.
A Reuss-type grain interaction was assumed as, in this case, the effect of the approximations related to the diffraction strain measurement can be studied separately from the approximations related to grain interaction.
Two grain interaction models have been considered: the unrealistic Reuss grain interaction and the more realistic Neerfeld-Hill grain interaction. 4 diffracting crystallites, i.e.

Material and experimental procedure The material selected is a ferrite/martensite dual phase steel in coarse grain (volume fraction martensite 46%, average grain size ferrite 32µm, average region size martensite 49µm) and fine grain conditions (volume fraction martensite 54%, average grain size ferrite 17µm, distributed martensite).
When a certain number of growing cracks had been observed, the specimen was dismounted and put into a micro-tensile device (Kammrath & Weiss) for in-situ testing in the SEM.
a) 33,000 cycles b) 62,500 cycles Fig. 2: Crack phase displacement in the coarse grained material The effect of the hard martensite phase and the soft ferrite phase on the crack path can be studied in more detail with coarse grained material.
The closed side of the crack is located around a grain boundary in the ferrite phase (dashed line).
Second, they may block the opening of the crack in ferrite grains adjacent to large martensite regions.

The matrix consisted of submicron alumina grains.
The SEM examination of the polished and etched surfaces revealed that the samples prepared from granulated powders consist of fine (grain size ≤ 1 µm) equiaxed alumina grains.
In the case of the CS5G, larger rod-like or plate-like grains are observed near the outer rim, embedded in the submicrometre-grained matrix of equiaxed alumina grains.
C at GB in the TG sample effectively hinders grain growth by GB pinning.
Acknowledgement The support of this work by the National Slovak Grant Agency under the contract N o 2/3101/23, the NATO Science for Peace Programme, project N o 97 41 22, by the Alexander von Humboldt Foundation and by the Maria Currie Fellowship under the contract number HPMF-CT-2002-01878, is gratefully acknowledged.

The samples with 0 mol% Li2O (NKN-5LT) consist of mostly equiaxed matrix grains with submicron-size and some abnormal grains, square or rectangular in appearance.
As the Li2O was added up to a maximum of 1 mol%, the number of abnormal grains and the grain size increased.
All the grains (the abnormal and the matrix grains) have faceted boundaries.
When more Li2O was added, the abnormal grains impinged upon each other in the samples, deterring further growth and consequently decreasing abnormal grain size.
The 7 mol% Li2O sample consists mostly of equiaxed matrix grains and no abnormal grains are present.

One solution to capture large-scale structures while considering a data template with a reasonably small number of grid nodes is provided by the multiple-grid method.
The multiple-grid method consists in simulating a number of increasingly finer grids.
There are only two states, pore space and grain, existing in sandstone.
The pore space is blue and the grain is gray.
Further experiments prove that the quality of reconstructed images will not be improved obviously when the number of multiple-grid is larger than three.

The results show that the cross-section morphology Cu6Sn5 of the solder joint interface is scallop-like and its section morphology is circle-like grain.
From the Fig.3, it shows that there are lots of circular-like and paraboloid-like compound microaggregates, and most of these grains are contected 5-7 other grains in the Fig.3, and these grains are determined as Cu6Sn5 from the atom number proportion achieved by composition analysis and the literatures [9-13].
The forming reason of Ag3Sn phase is described as below: the Ag3Sn grain can be stochastic moving at certain speed rate in the solidifying process of the solder alloy, and it maybe hit the surface of the Cu6Sn5 compound because of heat motion, and then the Ag3Sn grain will be captured by the adsorption action during soldering, because of the higher activity existed in the interface.
Surface morphology of interfacial Cu6Sn5 is circle-like grains and its cross-sections morphology is scallop-like between the Sn-2.5Ag-0.7Cu-0.1RE and the Cu substrate after soldering. 2.

The element Y is distributed mainly at the grain boundaries.
The atoms in grain boundary are looser, with more vacancies and other defects. the segregation of Y atoms in the grain boundary will reduce the free energy, which is a spontaneous process of thermodynamics, so Y atoms easy to gather in the grain boundaries, and then this cause uneven distribution of ingredients.
That’s because (1) Y can refine grains; (2) Y element increased nitrides in strengthened layer; (3) Y has solid solution hardening effect.
The reason why the wear resistance of W-Mo-Y co-diffusion and nitrided samples was much better than the samples treated by W-Mo-Y co-diffusion and nitriding was that (1) Y in alloying layer during plasma nitriding had a catalytic effect, which could promote the formation of a large number of nitrogen compounds; (2) the atomic radius of Y atoms was larger in the diffusion layer, which would cause a large distortion.
That’s because the solid solubility of Y in Fe was very low, Y distributed mainly at the grain boundaries and generated a small amount of intermetallic compound.

And we calculated out the average grain-size of sample according to the breadth of diffraction peak and the line broadening formula.
When we analyzed infrared absorption spectra in lower wave number (Fig.3), we could see there was a main character infrared absorption peak at 416 cm-1, which was Mg-O libration’s main characteristic absorption peak.
Based on relevant lattice geometry knowledge and formulas, XRD data, and the formula between diffraction peak width and line broadending D=0.89λ/B, we worked out the average grain size of sample ,shown in Table 1.