Shape Dependence of the Coarsening Behavior of Niobium Carbide Grains Dispersed in a Liquid Iron Matrix |
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Authors: | Kyung-Sik Oh Jae-Yong Jun Doh-Yeon Kim Nong M Hwang |
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Affiliation: | Center for Microstructure Science of Materials and School of Material Science and Engineering, College of Engineering, Seoul National University, Seoul 151–742, Korea;Korea Research Institute of Standards and Science, Taejon 306–600, Korea |
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Abstract: | In niobium carbide–iron (NbC-Fe) specimens where the grains were faceted, abnormally large grains appeared during coarsening. Normal and uniform grain growth occurred when the grain shape was changed to a spherical morphology by the addition of a small amount of boron. The results have been discussed, in terms of a coarsening mechanism, depending on the atomic structure of the interface. For faceted grains with an atomically smooth interface structure, the coarsening was suggested to occur via two-dimensional nucleation and a lateral-growth mechanism. For spherical grains with an atomically rough interfacial structure, diffusion was suggested to control the coarsening process. |
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Keywords: | niobium/niobium compounds coarsening morphology |
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