| The mechanical properties of heavily drawn bundled Cu-Nb filamentary microcomposite was examined as a function of Nb content. In order to predict the variation of the yield strength with Nb content, the interfilamentary spacing was calculated as a function of Nb content based on the assumption that Nb filaments are distributed regularly along the sides of a triangular unit cell in the transverse section. The yield stress consists of the substructure strengthening component due to elongated grains, subgrains and/or cells, the phase boundary strengthening term associated with the Hall-Petch type interaction between dislocations and phase boundaries and precipitate strengthening component. The contributions from phase boundary strengthening σ_(P.B.)(Cu-Nb), and precipitate strengthening σ_(ppt), increases with increasing Nb content. However, the contribution from substructure strengthening, σ_(sub)(Cu-Nb), decreases with increasing Nb content since more grain or subgrain boundaries are absorbed at Cu/Nb phase boundaries with increasing Nb content. The good agreement between the prediction and the experimental data suggests that the increase of the strength in Cu-Nb filamentary microcomposite with increasing Nb content results mostly from an increasing volume fraction of Nb filaments, which act as barriers to plastic flow. |
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