Internal Friction Peaks of Cold Worked Dilute Copper Alloys

The internal friction of cold worked dilute copper alloys (Cu-Ag and Cu-Au) is studied in the temperature range between -150°C and +140°C with an inverted torsion pendulum. The internal friction peaks which appear in cold worked pure copper are suppressed by the addition of solute atoms. In place of them two new peaks P a and P b are found at about -125°C and -60°C, respectively, in silver doped specimens, while no new peak is observed in gold doped ones. Detailed investigations are carried out on the behavior of the peak P b , which is interpreted to be due to thermal unpinning of dislocations from pinning silver atoms. The behavior of the other peaks is also described.