Hardening behavior of nickel-base alloy irradiated by multi-energy Fe ions

The multi-energy Fe ions irradiation was performed to avoid the effect of non-uniformity of the ion irradiation damage on the mechanical test of nickel-base alloy (UNS N10003). In this study, the hardening behavior of GH3533 alloy (nickel-base alloy) under the multi-energy Fe ions irradiation at RT and 700 °C was investigated by using nanoindentation, micro-pillar compression techniques, SEM and TEM. The hardness value saturated at 0.5 dpa at RT, according to the nanoindentation results, however the hardness curve sharply rose at the dose of 8 dpa at 700 °C. The plastic deformation curves of the samples at 700 °C had fewer jagged amplitude behaviors and no slip band on the surface, according to the stress-strain curves and in-situ SEM images obtained following the micro-pillar compression test. TEM characterization showed only the dislocation loops and lines were observed at the dose of 8 dpa at RT. However, at 700 °C, precipitates deprived of Fe and Ni and enriched in Mo and Cr were seen close to the dislocation lines at 700 °C. The smooth curves during micro-pillar compression at 700 °C and the abrupt increase in hardness were caused by the high density and uniform dispersion of these precipitates. Additionally, a technique for assessing the hardening behavior under multi-energy ion irradiation was devised, which combines nanoindentation with micro-pillar compression testing.