Modelling of the yield strength of a heavily wire drawn Cu-20%Nb composite by use of a modified linear rule of mixtures

Abstract

The strength of heavily wire drawn Cu-20 mass% Nb in situ composites considerably exceeds the predictions of the linear rule of mixtures (ROM). An analytical model for the calculation of the yield strength of Cu-20 mass% Nb wires is suggested. The approach is a modified linear rule of mixtures (MROM). It regards the yield strength of the composite as the sum of the volumetric weighted average of the experimentally observed yield strengths of the individual pure phases and a Hall-Petch type contribution arising from the impact of the Cu-Nb phase boundaries. The latter term is described in terms of dislocation pile-ups in the Cu matrix and dislocation movement and multiplication in the Nb filaments. The crystallographic texture and filament geometry of both phases is incorporated. The predictions of the model are in very good accordance with experimental data.