Role of displacement cascades in Ni clustering in a ferritic Fe-3.3at.%Ni model alloy: comparison of heavy and light particle irradiations

Abstract : The behavior of solute atoms in an undersaturated Fe-3.3at.%Ni model alloy upon heavy and light particle irradiations was investigated by Atom Probe Tomography. Whereas the first irradiations, performed using 27 MeV Fe ions at 400°C, highlight significant Ni enrichment on PD clusters, solute-rich features detected after 2.8 MeV protons H+ ions (400°C) and 1 MeV electron (320°C) irradiations are only associated with pre-existent microstructural defects. Nanoindentation tests shows no hardening in light particle irradiated samples, strongly suggesting that no dislocation loop formed. These observations put forward the importance of point defect clusters resulting from displacement cascades in Ni clusters’ formation.