| Budget Amount *help |
¥11,830,000 (Direct Cost: ¥9,100,000、Indirect Cost: ¥2,730,000)
Fiscal Year 2015: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
Fiscal Year 2014: ¥3,250,000 (Direct Cost: ¥2,500,000、Indirect Cost: ¥750,000)
Fiscal Year 2013: ¥6,630,000 (Direct Cost: ¥5,100,000、Indirect Cost: ¥1,530,000)
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| Outline of Final Research Achievements |
The higher-order gradient crystal plasticity (HOGCP) model that was proposed by the principal investigator has a potential capability to represent a wide range of size effects observed in mechanical properties of metals. However, methodology for modeling of interfaces (i.e. grain boundaries in polycrystals) has not yet been established. Thus, the HOGCP model could not represent the mechanical behavior of polycrystals precisely. In the present study, a new grain boundary model is proposed. In the model, it is assumed that yielding of grain boundaries occurs when the dislocation density at the grain boundary, which increases due to dislocation pileups, reaches a critical value. To confirm the validity of the model and to identify the material parameters included in the model, an experimental study using an ultra-fine grain metal (Al) was conducted. The experimental results suggested that the grain boundaries in the material did not act as strong barriers to dislocation motion.
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