TEM characterisation of heavy-ion irradiation damage in FeCr alloys

Abstract Heavy-ion damage in a series of FeCr binary alloys and pure Fe has been investigated by TEM. Specimens were irradiated in bulk with 1.5 MeV Fe + ions at an irradiation temperature of 300 °C. A TEM specimen preparation technique has been developed to access the peak of the buried damage region. The damage took the form of dislocation loops with sizes ranging up to a few tens of nanometres. Loops with Burgers vectors of type b = and b = ½ were both present in all the specimens, but the proportion of loops was higher in FeCr alloys than in pure Fe. In Fe–8%Cr the loop number density was determined to be (1.6 ± 0.2) × 1021 m-2. Nature determinations showed that loops in Fe–11Cr and ½ loops in Fe–8Cr were of interstitial type.