RADIATION-INDUCED DEFECTS IN SOLID-SOLUTIONS AND INTERMETALLIC COMPOUNDS BASED ON THE NI-AL SYSTEM .2. RECOVERY OF RADIATION-DAMAGE

The recovery of short-range-ordered Ni(Al) and Ni(Al,Ti) solid solutions and long-range-ordered Ni3Al intermetallic compounds was investigated by residual electrical resistivity measurements as a function of composition and of fluence, after low-temperature (4-9 K) irradiation with 2.95 MeV electrons. In the solid solutions, long-range defect migration resulted in increases of local order; self-interstitials were found to be mobile above 110 K (at least in the binary alloys) and vacancies to be mobile above 330 K. The recovery spectrum of irradiated intermetallic compounds showed some similarity with that of pure nickel, with a smaller amount of fine structure. The mobility of self-interstitials (corresponding mainly to Ni-Ni dumbbells) occurs at a higher temperature (75 K) than in nickel (50 K) and does not induce significant ordering. By contrast, the Ni vacancies, which are the dominant vacancy species, are slightly less mobile than in nickel and promote some increase of long-range order.