XRD investigation of the strain/stress state of ion-irradiated crystals

In this work, it is demonstrated that XRD is a powerful technique for the study of ion-irradiated materials. For this purpose, XRD experiments have been performed under different configurations on a 〈1 0 0〉-oriented yttria-stabilized zirconia single crystal implanted with 300 keV caesium-ions at 3 × 1014 cm−2. Initially, it is demonstrated that the depth strain profile can be determined from the refinement of a symmetric θ–2θ scan. Moreover, in order to explore the whole XRD data, a model that describes the strain/stress state of the damaged layer is proposed. This model takes into account the elastic response of the bulk material (substrate) underneath the irradiated layer. The measured elastic strain is then the sum of a free strain due to the formation of radiation-induced defects and of an additional strain arising from the substrate elastic reaction. Application of this model allowed the calculation of the different strain contributions and the stress experienced by the irradiated layer. It is shown that these parameters may reach large values (respectively 0.7% and −1.9 GPa) despite the low radiation damage level.