Nanoindentation Orientation and Solute-Influenced Deformation Mechanisms in Irradiated bcc Fe Binary Alloys

The objective of this study is to understand the influence of indentation orientation and solute type on the mechanical response of ion-irradiated binary ferritic alloys. Nanoindentation is a common method used to evaluate the irradiation hardening in ion-irradiated structural alloys because this technique allows one to target small regions of interest such as thin ion-irradiated regions in ion-irradiated alloys. However, variables including crystallographic orientation and ion implantation stress will influence the mechanical response and these influences should be well understood. As-received and irradiated Fe-P and F-N (001) grains have been indented along <001> and <011> directions to evaluate the crystallographic orientation dependent mechanical response in these materials. Binary substitutional and interstitial alloys were chosen to observe the influence of solute type on mechanical response. TEM imaging of indentation cross-sections revealed that indentation direction and solute type play important roles in the mechanical response in these alloys. This study demonstrates the importance of considering and accounting for influences of indentation direction in nanoindentation experiments especially in ion-irradiated alloys.