Microstructural design by combining nanograins and spinodal decomposition in a Fe-Cr alloy

Microstructure design of new high-performance alloys requires the combination of multiple hardening mechanisms. This study explores combining nanograins with spinodal decomposition strengthening in an Fe-51.4Cr (at.%) alloy. High-pressure torsion (HPT) produced a nanostructure with a 51 nm grain size. Atom probe tomography analysis of deformed and annealed samples revealed spinodal decomposition after one hour of annealing. HPT accelerated decomposition kinetics is due to the high vacancy concentration. Microhardness remained stable due to spinodal hardening, despite a decrease in the Hall-Petch strengthening contribution. However, fracture toughness decreased. [Display omitted]