Nano-hardening features in high-dose neutron irradiated Eurofer97 revealed by atom-probe tomography

B. Gómez-Ferrer (1) , C. Dethloff (2) , E. Gaganidze (2) , L. Malerba (3) , C. Hatzoglou (1) , Cristelle Pareige (1)

1 GPM - Groupe de physique des matériaux
2 KIT - Karlsruhe Institute of Technology
3 CIEMAT - Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas

Ageing of Cast Austenitic Stainless Steels (CASS) was attributed to the decomposition of the ferrite by spinodal decomposition and precipitation of G-phase particles. This leads to an increase in hardness and a decrease in Charpy-impact energy. It is possible to restore the mechanical properties of these steels by annealing treatment above the Fe-Cr miscibility gap in order to dissolve α' phase. In this work, an annealing treatment for 2 h at 550 °C followed by water quenching was applied to various Mo-free and Mo-bearing steels. This treatment allowed to restore almost completely the mechanical properties of Mo-free steels and partly Mo-bearing steels regardless of the initial ageing time. The mechanical property changes were attributed to the complete dissolution of spinodal decomposition and complete or partial dissolution of G-phase particles. After annealing, a re-ageing kinetics was studied. The preexisting G-phase particles have minor influence on the kinetic of spinodal decomposition until 2,400 h at 400 °C.

Domaines: Science des matériaux [cond-mat.mtrl-sci]; Matériaux

B. Gómez-Ferrer, C. Dethloff, E. Gaganidze, L. Malerba, C. Hatzoglou, et al.. Nano-hardening features in high-dose neutron irradiated Eurofer97 revealed by atom-probe tomography. Journal of Nuclear Materials, 2020, 537, pp.152228. ⟨10.1016/j.jnucmat.2020.152228⟩. ⟨hal-02942855⟩