著者

北村 隆行 屋代 如月 大谷 隆一

出版者

一般社団法人日本機械学会

雑誌

日本機械学會論文集. A編 (ISSN:03875008)

巻号頁・発行日

vol.62, no.600, pp.1813-1819, 1996-08-25

被引用文献数

5

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In order to elucidate the mechanism of deformation and fracture of microcomponents, numerical simulations are conducted for nanoscopic wire and film of nickel without lattice defects using molecular dynamics on the basis of the EAM (embedded atom method) potential. Applying a periodic boundary, large as well as small materials are subjected to a tensile strain along the [001] direction of the FCC (face-centered cubic) lattice. Here, the traverse stresses, σ_<xx> and σ_<yy>, in the former are kept at zero during the tension. The yield is brought about by the crystallographic slips on the (111) planes and there is little difference in the yield stresses among the wire, film and bulk. The slips continue to take place on multiple (111) planes and the plastic deformation leads to ductile fracture. Then, the displacement in the traverse direction on the cell boundaries of bulk is fixed in order to investigate the effect of constraint. It shows brittle fracture due to cleavage cracking. this implies that the constraint, which may be introduced by local inhomogeneity of the material, brings about early crack nucleation and reduces the ductility of matcrials without lattice imperfection.