Recovery of irradiation-induced defects in high-purity iron and iron–carbon solid solutions

Isochronal annealing of electron irradiated and unirradiated carbon–iron alloys (350 and 700 at ppm carbon), as well as of irradiated high purity iron, has been studied by electrical resistivity measurements in the temperature range from 4.2 to 450 °K. A new recovery stage (3%) is revealed centered at 21 °K in both the alloys and the high purity iron. The presence of carbon in solution suppressed the IE recovery stage (130 °K) while no effect was found on recovery stages below this temperature. This supports the interpretation that irradiation softening found in iron at low temperatures is due to direct effect of self-interstitials. In the temperature range 250 to 300 °K the quenched and irradiated alloy specimens exhibited resistivity increase upon pulse annealing. On the other hand, the as-quenched alloy specimens showed only a simple recovery above 270 °K. A possible explanation for the appearance of this resistivity increase is discussed.