EXPERIMENTAL INVESTIGATION AND MODELING OF THE INFLUENCE OF MICROSTRUCTURE ON THE RESISTIVE CONDUCTIVITY OF A Cu-Ag-Nb IN SITU COMPOSITE

摘要

A Cu-8.2 wt Ag-4 wt Nb in situ metal matrix composite was manufactured by inductive melting, casting, swaging, and wire drawing. The final wire (η = ln(Ao/A) = 10.5, A: wire cross section) had a strength of 1840 MPa and 46 of the conductivity of pure Cu. The electrical resistivity of the com- posite wires was experimentally investigated as a function of wire strain and temperature. The microstruc- ture was examined by means of optical and electron microscopy. The observed decrease in conductivity with increasing wire strain is interpreted in terms of inelastic electron scattering at internal phase bound- aries. The experimental data are in very good accord with the predictions of an analytical size-effect model which takes into account the development of the filament spacing as a function of wire strain and the mean free path of the conduction electrons as a function of temperature. The experimentally obtained and calculated resistivity data are compared to those of the pure constituents.