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※ 半角英数字
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Nanoscale contact plasticity of crystalline metal; Experiment and analytical investigation via atomistic and discrete dislocation models

結晶金属のナノスケールにおける接触塑性; 実験及び原子,離散転位モデルによる検討

都留 智仁; 渋谷 陽二*; 加治 芳行

Tsuru, Tomohito; Shibutani, Yoji*; Kaji, Yoshiyuki

結晶金属のナノスケールにおける初期塑性変形は転位の集団的運動によって生じる。この現象はナノ塑性として知られており、マクロな変形の素過程であると考えられているがその詳細は現在もわかっていない。本研究では、実験、及び原子・離散転位モデルによる解析を行いナノスケールの接触問題について包括的な研究を行った。その結果、接触問題では転位の生成が内部領域で理想強度より大きなせん断応力で生じることを示すとともに転位双極子がナノスケールの塑性変形を引き起こすことを示した。

Nanoscale incipient plastic deformation in crystalline metals occurs as the result of the collective motion of dislocations. It is known as "nanoplasticity" and recognized as the elementary process of the macroscopic deformation. In the present study, experimental tests are first conducted to educe the unique nature of the nanoscale deformation. Subsequently large-scale atomistic simulations are performed to predict the incipient plastic deformation and a new discrete dislocation model combined with the boundary element analysis is constructed to capture the collective motion of the dislocations. Our results suggest that the incipient plastic deformation requires much higher critical shear stress than the theoretical shear strength due to high compressive stress distribution beneath the indenter, and that the displacement burst is induced by surface rearrangement corresponding to hundreds of dislocation dipoles.

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パーセンタイル:22.98

分野:Materials Science, Multidisciplinary

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