HIGH-TEMPERATURE OXIDATION OF ION-IMPLANTED 2011-ALUMINUM ALLOY

The oxidation of type 2011 aluminium alloy (5.5% Cu, 0.5% Pb, 0.5% Bi nominal) implanted with Ti or Cr ions has been investigated as a funct ion of dose (1 x 10(15)-4 x 10(16) cm-2) and annealing time in an oxyg en atmosphere at 500-degrees-C. With both ions, a decrease in oxidatio n was observed for doses at the lower end of the ranges studied. This effect was more pronounced in the case of Cr implantation where a maxi mum reduction of approximately 30% was observed for a dose of 1.7 x 10 (15) cm-2 following an oxidation time of 2.5 h. At higher doses, the i mplantation of these ions resulted in an increase in the rate of oxida tion. In addition, RBS measurements were performed which indicated red istribution of Cu and Fe and surface segregation of Pb or Bi. These fi ndings are discussed in the light of possible oxidation mechanisms.