Abstract:The electron backscattering diffraction (EBSD) technique has made it quite easy to obtain the grain area distribution in a planar section of the polycrystalline materials. Usually, area-weighted grain area and number-weighted grain area show completely different distribution profiles. Instead of the nominal average grain size calculated from the grain area distribution results, the spatial grain size and its distribution character reflect the real features of the materials and those parameters are expected thr… Show more
“…The grain size for every particle ( D g ) was also calculated as the projected area diameter: where A g was the area of the grain section. The values obtained were classified and weighted in area to obtain the particle size distribution; the average grain size ( D 50 ) was taken as the median value of this area‐weighted distribution …”
In this study, thin, flat sheets, about 90 μm thick, were prepared from ceria‐doped scandia‐stabilized zirconia with molecular formula 10Sc2O3·1CeO2·89 ZrO2 (10Sc1CeSZ) by tape casting and subsequent sintering at different thermal cycles. A sintering thermal cycle was selected that yielded defect‐free flat sheets, with practically negligible porosity (between 0.35% and 0.10%) and average grain diameters ranging from 1.32 to 6.30 μm. Ionic conductivity at 600°C was as high as 21 mS/cm. Ionic conductivity increased with average grain diameters up to 2.7 μm. At higher average grain diameters, conductivity remained practically constant.
“…The grain size for every particle ( D g ) was also calculated as the projected area diameter: where A g was the area of the grain section. The values obtained were classified and weighted in area to obtain the particle size distribution; the average grain size ( D 50 ) was taken as the median value of this area‐weighted distribution …”
In this study, thin, flat sheets, about 90 μm thick, were prepared from ceria‐doped scandia‐stabilized zirconia with molecular formula 10Sc2O3·1CeO2·89 ZrO2 (10Sc1CeSZ) by tape casting and subsequent sintering at different thermal cycles. A sintering thermal cycle was selected that yielded defect‐free flat sheets, with practically negligible porosity (between 0.35% and 0.10%) and average grain diameters ranging from 1.32 to 6.30 μm. Ionic conductivity at 600°C was as high as 21 mS/cm. Ionic conductivity increased with average grain diameters up to 2.7 μm. At higher average grain diameters, conductivity remained practically constant.
“…Figure 3 shows the area-weighted grain size distribution of the annealed microstructures obtained by OIM analysis after the twin boundary (S3) deletion treatment, and the function fitting curves obtained by a lognormal function. According to the proposed method for the determination of the mean grain size from the areaweighted grain size distribution profile, 14) the mean grain sizes of the 1 173 K annealed microstructures turned out to be 0.84, 1.96, and 2.43 mm for heating rates of 9.3, 3.1 and 0.93 K/s, respectively. Table 2 shows the mean grain sizes of the annealed microstructures at different heating rates and target temperatures.…”
, in the equation is calculated and is found to follow the equation PϭK · exp(0.5/q). Meanwhile, the grain growth exponent, n, for the anisothermally annealed SUS316L steel is also determined and is found to lie between 2.5 and 3.0. On the other hand, EBSD analysis of the evolved microstructure at different heating rates indicates that low heating rate caused partial recrystallization with preferred orientations at the recrystallization finish temperature, while high heating rates above 1 K/s induced the homogeneously nucleated recrystallization microstructure with random orientations and a lognormal type grain size distribution.
“…The grain shapes are thought to resemble that following a Poisson-Voronoi tessellation [60,61,62] (see also [63,64]), and thus S ve relates to the grain size as [60]:…”
Section: Formation Of Cell Walls/grain Boundariesmentioning
This paper presents a model which quantitatively predicts grain refinement and strength/hardness of Al alloys after very high levels of cold deformation through processes including cold rolling, equal channel angular pressing (ECAP), multiple forging (MF), accumulative rolling bonding (ARB) and embossing. The model deals with materials in which plastic deformation is exclusively due to dislocation movement, which is in good approximation the case for aluminium alloys. In the early stages of deformation, the generated dislocations are stored in grains and contribute to overall strength. With increase in strain, excess dislocations form and/or move to new cell walls/grain boundaries and grains are refined. We examine this model using both our own data as well as the data in the literature. It is shown that grain size and strength/hardness are predicted to a good accuracy.
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