Zener Relaxation in CuAl Single Crystals Studied by Isothermal Mechanical Spectroscopy

Abstract
The Zener relaxation was studied in Cu-Al single crystals. All samples were cut with the same orientation and the Al concentrations were ranged between 3 and 19 at. % Al ( solid solution). For low temperature experiments ( < 550°K ), perfect Debye peaks are observed in all samples and the relaxation strength is proportional to the concentration square according with the pair reorientation Zener theory. At higher temperatures and for samples with higher Al concentration only, the internal friction peaks are broader. In the sarne time, the relaxation strength first increases and then decreases with the measurement temperature according to the short-range ordering LeClaire-Lomer theory with respectively the influence of only neighbouring and more distant atoms.