TEM characterisation of heavy-ion irradiation damage in FeCr alloys

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 degrees 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 = < 100 > and b = 1/2 < 111 > were both present in all the specimens, but the proportion of < 100 > 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) x 1021 m-2. Nature determinations showed that < 100 > loops in Fe-11Cr and 1/2 < 111 > loops in Fe-8Cr were of interstitial type. (C) 2009 Elsevier B.V. All rights reserved.