Radiation-induced defects in solid solutions and intermetallic compounds based on the Ni-Al system: I. Low-temperature electron-irradiation damage

Abstract

The effect of alloy composition on radiation damage by 2.95 MeV electrons at low temperature has been investigated in Ni(Al) and Ni(Al,Ti) solid solutions and in Ni3Al intermetallic compounds (24.6-26.5 at.% Al) by residual electrical resistivity measurements. In the solid solutions the main result of irradiation was point-defect production. Frenkel-pair resistivities, deduced from the comparative analysis of the initial damage rates in the solid solutions and in pure nickel, were 6.5-9.4 mu Omega cm/%, similar to or slightly larger than the value of nickel. In Ni3Al intermetallic compounds, the resistivity damage rates were enhanced by a factor of about 15 compared with pure nickel. Disordering contributes only a small part of the increase. Assuming an average of 3+or-1 replacements per displacement, a comparison of the initial damage rates in nickel and in the compounds leads to Frenkel-pair resistivities ranging from 97 to 109 mu Omega cm/%. Such high values may be correlated with the large ideal resistivity of these materials.

Determination of threshold energies for displacements of Fe and Rh atoms in Fe-50at.%Rh intermetallic compound by using energetic electron irradiation at low temperatures

“…For other metallic compounds, however, the electrical resistivities per unit concentration of Frenkel pairs are also much larger than for pure metals. For example, the values of q F for Fe 0.6 Al 0.4 and Ni 3 Al are 71 lX cm/at.% and 102 lX cm/at.%, respectively [11,12]. In the crystal of intermetallic compounds, as two kinds of atoms are arranged regularly in sequence, atomic disordering induced by Frenkel pairs contributes to the electrical resistively much more pronouncedly than in pure metals.…”

Defects in Metals

“…Relative changes in the defect concentration, for example during irradiation and subsequent annealing, can be monitored precisely, whereas the absolute concentration can be determined only if the magnitude of the specific contribution is known. The method can be applied equally to point defects in pure metals (Lucasson and Walker, 1962), disordered and ordered alloys (Sharma et al, 1978;Vaessen et al, 1984;Karsten et al, 1991;Gilbert et al, 1973;Rivière et al, 1980;Alamo et al, 1986;Dimitrov et al, 1992aDimitrov et al, , 1992bSattonnay et al, 1997). As the contributions from various defects are integrated into a single value, however, discrimination of multiple defect species, if present, is impossible.…”