Internal Friction Peaks of Cold-Worked Dilute Copper-Aluminium Alloys(Metallurgy)

Abstract The internal friction of cold-worked Cu-Al alloys is measured with an inverted torsion pendulum in the temperature range between − 180°C and + 100°C. Among 10 specimens with different contents of aluminium ranging from 0·01 to 2 at.%, distinct peaks are observed for the two compositions, 0·13 and 0·18 at. % Al, the peak height being larger for the former; detailed studies are made on 0·13 at. % Al specimens. The peak is introduced by plastic deformation and disappears on annealing at temperatures around + 150°C. For a specimen annealed in an oxidizing atmosphere prior to the final deformation, the peak is no longer observed. The peak is considered to be a combined effect of dislocations and aluminium atom-vacancy complexes.