Effects of chromium on the one-dimensional motion of interstitial-type dislocation loops in iron

The one-dimensional motion of interstitial-type dislocation loops in Fe–9Cr ferritic alloy is studied by in situ transmission electron microscopy. Loop motion is examined under 1000 kV high-energy electron irradiation at temperatures ranging from 110 to 680 K and under thermal annealing from 295 to 960 K without introduction of additional displacement subsequent to the irradiation at 110 K. The results are compared with those in pure bcc Fe, and the effects of Cr on the motion of loops are extracted. Under high-energy electron irradiation, the motion frequency of loops is only slightly reduced by Cr. In contrast, under annealing, the motion frequency of loops in Fe–9Cr is significantly reduced by Cr. The origins of such two-way effects of Cr on the motion frequency of loops are discussed.