Effects of irradiation and strain in a bronze processed multifilamentary Nb3Sn superconducting composite

The influence of fast neutron irradiation on critical current I
c
, mechanical properties and the strain dependence of I
c
for a bronze processed fine multifilamentary Nb
3
Sn superconducting composite has been investigated. The neutron irradiation has been performed in a fission reactor at the reactor ambient temperature (<355 K) up to a neutron fluence of 3.6×10
¹⁹
n/cm
²
(E
n
>0.1 MeV). The effect of annealing after irradiation has also been investigated. It has been found that the composite grows harder and more brittle with irradiation. The strain which gives the maximum I
c
in I
c
vs. strain relation is increased with irradiation. The reversibility of strain induced change in I
c
is degraded by irradiation. Annealing at 723 K and 973 K (2 hr) after 3.6×10
¹⁹
n/cm
²
irradiation recovered successively the mechanical properties and strain dependence of I
c
up to the levels before irradiation.