ELECTRICAL-PROPERTIES OF RAPIDLY SOLIDIFIED CU-CR ALLOYS

The effect of rapid solidification of Cu-2.3 at.-%Cr and Cu-3.1 at.-%Cr alloys by melt spinning and of subsequent aging on their electrical properties has been investigated and discussed on the basis of Matthiessen's hypothesis. Melt spinning was found to increase the chromium content in solid solution from the maximum equilibrium solubility of 0.8 at.-% to more than 3 at.-%. In this state, the variation of resistivity as a function of the chromium content appears to be a simple linear extension of the relationship obtained for Cu-Cr alloys after solid state quenching. The measurements on aged ribbons indicate that their conductivity changes from about 10% IACS in the melt spun condition to a maximum of 60% IACS in the overaged condition. The presented evaluations lead to the conclusion that the resistivity of melt spun alloys is controlled by the spacing between chromium atoms in solid solution, whereas the resistivity of these alloys after aging is controlled by the spacing between chromium particles, both of these spacings being much smaller than the mean free path of electrons in copper.