Frictional Force on a Fast Moving Dislocation in Copper and Its Dilute Alloys

Abstract

By means of ultrasonic attenuation measurements in megacycle range, the frictional force on a fast moving dislocation is studied in pure Cu and Cu-Mn, Cu-Ni, Cu-Ge, Cu-Pd and Cu-Pt dilute alloys from 4.2°K to 273°K. The magnitude of the damping constant, B , deduced from asymptotic behavior of the attenuation at high ultrasonic frequencies, is found to depend on the solute concentration and the atomic size of the solute atom, but rarely depend on the difference of the electronic state, the stacking fault energy or the mass of the solute atom. Empirical formulae for B in these alloys in the temperature from 54°K to 273°K are given, where B is expressed as a function of the misfit parameter. A tentative explanation of the impurity effect is given as an elastic interaction between an impurity atom and the dislocation. The explanation seems to give a right order of magnitude of the damping constant.