| Budget Amount *help |
¥17,030,000 (Direct Cost: ¥13,100,000、Indirect Cost: ¥3,930,000)
Fiscal Year 2015: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
Fiscal Year 2014: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
Fiscal Year 2013: ¥9,100,000 (Direct Cost: ¥7,000,000、Indirect Cost: ¥2,100,000)
Fiscal Year 2012: ¥3,770,000 (Direct Cost: ¥2,900,000、Indirect Cost: ¥870,000)
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| Outline of Final Research Achievements |
We employed a simple physical model of a grain boundary in discussing the segregation of alloying elements in iron, stating that the grain boundary has a constant thickness and that Gibbs energy can be assigned to the boundary material. The regular solution model was applied to the bulk and the grain boundary, and in particular, the Gibbs energy of the grain boundary was expressed as that of the liquid phase in Fe-based binary systems. It seems unusual to apply the Gibbs energy of a liquid to a grain boundary; however, it could be reasonable when considering the structural analogy between an amorphous phase and a grain boundary composed of simple structural units. In fact, the calculated segregation coefficient of boron agrees fairly well with the experimental value. The result provides us with an insight into grain-boundary segregation as an ordering process, where the added element is placed in the vacant site in polyhedral clusters.
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