Electrical Resistivity of Internally Oxidized Cu–Al Alloys

Abstract

The electrical resistivities at room temperature have been investigated precisely after partial and complete internal oxidation. The internal oxidation rates obtained through electrical resistivity measurements are always smaller than the real rates which are obtained metallo-graphically. This suggests that the resistivities of subscales after partial internal oxidation are greater than those after complete internal oxidation, and that it is wrong to estimate internal oxidation rates through resistivity measurements. After complete internal oxidation, deviations from Matthiessen's rule (DMR) are observed in the internally oxidized Cu–Al alloys. The DMR's at 20°C have the same magnitudes as those of the residual resistivities and are nearly proportional to the volume fraction of dispersed Al2O3 particles. The DMR at 20°C in the Cu–1.0 vol%Al2O3, alloy is 0.037 µΩ-cm. The origin of the DMR is attributed to dispersed oxide particles.