Tomohito Tsuru1,2, Yoshiteru Aoyagi3, Yoshiyuki Kaji1 and Tomotsugu Shimokawa4
1Nuclear Science and Engineering Directorate, Japan Atomic Energy Agency, Tokai-mura, Ibaraki 319-1195
Huge-scale atomistic simulations of shear deformation tests to the aluminum polycrystalline thin film containing the Frank-Read source are performed to elucidate the relationship between the inter- and intragranular plastic deformation processes and the mechanical properties of ultrafine-grained metals. Two-types of polycrystalline models, which consist of several grain boundaries reproducing easy and hard slip transfer, respectively, are prepared to investigate the effect of grain boundary on flow stress. While the first plastic deformation occurs by the dislocation bow-out motion within the grain region for both models, the subsequent plastic deformation is strongly influenced by the resistance of the slip transfer by dislocation transmission through grain boundaries. The influence of the competition between the intragranular dislocation nucleation and intergranular slip transfer on the material strength is considered. The nanostructured material's strength depending on local defect structures associated with grain size and dislocation source length is assessed quantitatively. [doi:10.2320/jinstmet.J2013039]
intragranular dislocation nucleation, intergranular slip transfer, bulk nanostructured metals, ultra-fine grained metals, grain boundary, dislocation source, mechanical property, atomistic simulation
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