Dislocation-Solute Interaction Studied by Amplitude-Dependent Internal Friction in Al-0.01 at%Si Alloy

Abstract

Amplitude-dependent internal friction was measured at the temperature range of 2–15 K on Al-0.01 at%Si single crystal and 99.999%Al. From the temperature dependence of applied strain under a constant internal friction, the binding energy U₀ between a dislocation and a pinning obstacle was determined as 0.5–0.8 eV in Al-0.01 at%Si and 0.05–0.06 eV in 99.999%Al. The value of U₀ for Al-0.01 at%Si is very large and cannot be explained as a dislocation—a single solute atom interaction. Silicon atoms in Al probably precipitated into clusters because of the very low solubility, and dislocations were thought to be pinned strongly by Si clusters.