Interface Character Distributions in WC–Co Composites
01 Mar 2008-Journal of the American Ceramic Society (John Wiley & Sons, Ltd)-Vol. 91, Iss: 3, pp 996-1001
TL;DR: The geometric and crystallographic characteristics of interfaces in WC-Co composites with a range of grain sizes and carbide volume fractions have been comprehensively characterized in this article, showing that the average number of carbide vertices per grain and the basal-to-prismatic face area ratio of the WC-co interfaces increase with the carbide volumes fraction.
Abstract: The geometric and crystallographic characteristics of interfaces in WC–Co composites with a range of grain sizes and carbide volume fractions have been comprehensively characterized. The carbide crystals are most frequently terminated by (0001) and ð10 10Þ surfaces. The average number of carbide vertices per grain and the basal-to-prismatic face area ratio of the WC–Co interfaces increase with the carbide volume fraction. The three most frequently occurring WC/WC grain boundaries are 901 twist boundaries about ½10 10� ,3 01 twist boundaries about [0001], and asymmetric 901 boundaries about ½ 2110� .T he boundary populations do not vary with grain size or carbide volume fraction, suggesting that they are determined by the grain boundary energy anisotropy.
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Cites background from "Interface Character Distributions i..."
...Co composites (Kim et al., 2008) that the contiguity of WC particles is scale-invariant with a given particle volume fraction....
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TL;DR: In this article, three-dimensional electron backscatter diffraction data, obtained by serial sectioning a nickel-base superalloy, has been analyzed to measure the geometric arrangement of grain boundary planes at triple junctions.
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TL;DR: In this paper, the authors reviewed recent findings from two-and three-dimensional orientation mapping studies and confirmed a strong inverse correlation between the relative energies of grain boundaries and the frequency with which they occur in microstructures.
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559 citations
TL;DR: In this article, the authors review techniques that can be used to study the mesoscopic crystallographic structure of grain boundary networks and summarize current findings, showing that grain surfaces within dense polycrystals favor the same low energy planes that are found on equilibrium crystal shapes and growth forms of crystals in contact with another phase.
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236 citations
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215 citations
TL;DR: In this paper, a method for estimating the distribution of grain-boundary types in polycrystalline materials on the basis of observations from a single planar section is described.
Abstract: A stereological method is described for estimating the distribution of grain-boundary types in polycrystalline materials on the basis of observations from a single planar section. The grain-boundary distribution is expressed in terms of five macroscopically observable parameters that include: three parameters that describe the lattice misorientation across the boundary and two parameters that describe the orientation of the grain-boundary plane normal. The grain-boundary distribution is derived from measurements of grain orientations and the orientations of the lines formed where grain boundaries intersect the plane of observation. Tests of the method on simulated observations illustrate that the distribution of boundaries in a material with cubic symmetry can be reliably determined with about 10° of resolution from the analysis of 5×104 or more line segments. Furthermore, grain-boundary distributions directly observed from serial sections of a SrTiO3 polycrystal are compared to those resulting from the stereological analysis of a single plane. The comparison shows that the stereological method provides a reasonable estimate of the measured distribution. The differences between the directly observed grain-boundary distribution and that derived from the stereological analysis are consistent with the results from the simulation.
189 citations
TL;DR: In this article, a comparative study of Co/WC and Co/TiC interface adhesion was performed using first-principles density-functional plane-wave pseudopotential calculations.
Abstract: With the purpose to understand the fundamental difference between two industrially important classes of hard materials, WC-Co cemented carbides and TiC-Co cermets, we do a comparative study of Co/WC and Co/TiC interface adhesion. Using first-principles density-functional plane-wave pseudopotential calculations, we analyze the energetics and electronic structure of the Co/WC interface, and compare with previously reported results for Co/TiC. Values for the work of separation and the interface energy are provided for a set of model Co(001)/WC(001) interfaces with fcc Co and cubic WC, which is a relevant case in sintering of Ti(W)C-Co cermets. The known fact of better wetting for Co on WC than on TiC is confirmed and explained in terms of the electronic structure. Both Co/WC and Co/TiC are characterized by strong covalent Co-C interface bonds. The stronger adhesion in the Co/WC case originates from a larger contribution of the Co-W metal-metal bonding rather than from the Co-C bonds.
148 citations