Heavy-ion irradiations of Fe and Fe–Cr model alloys Part 2: Damage evolution in thin-foils at higher doses

Abstract

Abstract\n We continue our study of heavy-ion damage in Fe and FeCr alloys started in Part 1[1] with an investigation of damage development in UHP Fe and Fe8%Cr at higher doses up to 2 x 1019 ions m-2 (~13 dpa). In thin-foil irradiations with 150 keV Fe+ ions at 300oC and room temperature (RT), more complex microstructures started to develop in thicker regions of the foils at doses greater than about 2 x 1018 ions m-2, seeming to involve cooperative interaction, alignment and coalescence of smaller loops. First strings of loops all with the same ?<111> Burgers vectors formed. In UHP Fe irradiated at 300oC the damage then developed into colonies of resolvable interstitial loops with ?<111> Burgers vectors. By a dose of 2 x 1019 ions m-2, large (several hundred nanometre) finger-shaped loops with large shear components had developed by the growth and subsequent coalescence of smaller loops. Similar but finer-scale damage structures developed in UHP Fe irradiated at RT and in Fe8%Cr irradiated at both RT and 300oC.