Effects of composition and neutron irradiation on the superconducting properties ofNb3Al

Abstract

Phase-equilibrium and neutron-irradiation studies have been carried out on the Nb-Al system in the $A15$ phase region. The $A15$ phase boundary extends from 20-24 at.% Al at 1730°C, with a maximum $T_c$ midpoint at 18.6 K. Irradiation with reactor neutrons produces large reductions in $T_c$, which are accompanied by decreases in the long-range order parameter $S$ and increases in the lattice parameter $a_0$. These changes are completely reversible on annealing.