The Effects of Impurities on Void Formation in α-Iron

Abstract

A number of previous observations of the void formation induced in a variety of metals by fast neutrons or other bombarding particles have indicated that the degree of metal purity can have a significant effect on the void production rate. Increasing impurity content seems, in general, to reduce void formation, but some cases have been reported in which low concentrations of certain impurities significantly increased void production over that seen for the pure metal.In the current investigation, zone-refined iron and five low-concentration alloys of zone-refined iron were studied following irradiation with 8.8 × 1020 neutrons per cm2 < 0.18 MeV at 280°C. The five alloys contained 0.3 at-% Cu, 0.3 at-% Ni, 0.3 at-% V, 0.3 at-% P, and 0.1 at-% C, respectively. Since the voids produced by these irradiation conditions were very small, the out-of-focus observation technique suggested by Ruhle was employed in this study.