Deuterium-defect trapping in ion-irradiated zirconium

Trapping of ion-implanted deuterium by lattice defects in zirconium has been investigated. The lattice defects were generated by 4 MeV Zr+ (self ion) irradiation of pure zirconium metal at 750 K. Following 100 keV deuterium implantation of the predamaged zirconium, concentration versus depth profiles were measured by a method of nuclear microanalysis. The specimens were aged ata variety of temperatures and further profiles were measured. The measured migration of the deuterium was analyzed by solving a system of differential equations involving a diffusion and reversible trapping term. The results indicate that most of the deuterium is retained in traps with binding enthalpy approximately (0.28+-0.06) eV below that for normal equilibrium sites. Evidence also suggests some defect trapping at other binding enthalpies. The solubility of deuterium in zirconium at T=473 K was also measured on a specimen exposed to deuterium gas; the value obtained by nuclear microanalysis was determined to be (0.50+-0.10) at%. (orig.)