605 金属結晶粒界近傍の格子欠陥と粒界強度との関連性評価(OS1-(2) 計算力学と数値シミュレーション,オーガナイズドセッション)

概要

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Polycrystalline metal with the grain size less than 200 A^^. shows lower strength as decreasing its grain size, and this is the known fact as "Inverse Hall-Petch effect". The possible reason of this effect is that the macroscopic strength of polycrystals with small grains depends on rather the strength of grain boundary (GB) than crystal slip activity, since there is no enough space for dislocations to move around in such a small grain. In this study, scoping at the free volume at grain boundaries, we investigate the relationship between the free volume and grain boundary strength, based on molecular dynamics simulations for a single crystal, several different CSL grain boundaries (Σ3 and Σ9), and void structures instead of GB. The results show that (1) the strength of GB becomes lower when its free volume is higher, (2) even with the same amount of free volume, the CSL GB structure is stronger than the void structure.
一般社団法人日本機械学会の論文
2009-08-25