Production and annealing of point defects in electron-irradiated copper-gold alloys

Minimum displacement threshold energies for copper atoms in ordered and disorder Cu3Au and CuAu were determined at 20 K by electrical resistivity measurements during high energy electron bombardment: Esub(d min)sup(Cu) (20 K) = 18 eV in all cases. Previously obtained defect production curves are reanalysed. The recovery of damage introduced by irradiation at 20 K with 0.66 and 2.36 MeV electrons was studied in the ordered compounds: the same stages are observed whatever the incident electron energy; this suggests a single type of interstitial (Cu) migrating freely at 70 K; the Au interstitial is thought to take the place of a Cu atom and produce a Cu interstitial associated to an antistructure defect. For the disordered alloys, the recovery after irradiation with 2.4 MeV electrons is continuous from 20 to 250 K. For the four studied alloys, migration of vacancies occurs around 300-400 K and is responsible for long-range ordering of copper and gold atoms. (author)