Oxide dispersion strengthened FeCoNi concentrated solid-solution alloys synthesized by mechanical alloying

FeCoNi concentrated solid-solution alloys (CSAs) and its modified version strengthened by in-situ formed nano-sized particles are successfully manufactured through mechanical alloying and spark plasma sintering method. Both the as-milled powders and the bulk materials are of single face-centered cubic structure. After sintering and heat treatment, grains are refined by 68% with the addition of oxides. In oxide dispersion strengthened (ODS) FeCoNi CSAs, the majority of nano-sized particles with diameter ranging from a few to similar to 40 nm are uniformly distributed in the matrix, and most of them are identified as Y2Ti2O7. Electron backscattered diffraction results reveal that the recrystallization process is suppressed due to the existence of the nano-sized particles. The size and distribution of oxide particles in the matrix can be controlled by adjusting experiment parameters of the mechanical alloying process and annealing treatment. Refined grains and high-density nano-sized particles result in enhanced compressive yield strength for ODS-FeCoNi CSAs at room temperature and 700 degrees C, which is 1295 MPa and 127 MPa, respectively.