抄録
Tensile loading simulation of a nano-sized pillar-shaped polycrystalline thin film which has a preferred orientation in a specific direction was conducted, and effect of grain size on deformation behavior was examined by the molecular dynamics analysis. The model which was constructed by 2-dimensional Voronoi tessellation consisting of a columnar aggregate of cubic crystals with fiber texture whose axis was ＜110＞,＜100＞ and ＜111＞ direction perpendicular to the film surface. The uniaxial displacement was applied to the models to obtain the deformation behavior of thin film. In the stress.strain relationship, the average atomistic stress increases monotonously with increasing applied strain. After taking a maximum value, the average stress decreases moderately with applied strain. The 0.2% offset stress increases with decreasing grain size following by Hall-Petch relation if the grain is larger than15nm. However, the offset stress decreases with decreasing grain size following by inverse Hall-Petch relation if the grain is smaller than15nm. The transgranular strain increases with increasing applied strain. However, when the stress.strain relationship becomes nonlinear, the transgranular strain decreases with applied strain.
