Microstructure and mechanical properties of in-situ oxide-dispersion-strengthened NiCrFeY alloy produced by laser powder bed fusion

Oxide dispersion strengthened (ODS) superalloys are widely used in aerospace and nuclear reactors due to their exceptional creep strength and fatigue crack resistance at elevated temperature. In this work, an ODS NiCrFeY alloy for high temperature applications was fabricated by laser powder bed fusion (L-PBF). The microstructure and mechanical properties at room and elevated temperature of the L-PBF processed ODS NiCrFeY alloy were investigated. It was demonstrated that equiaxed grains with large fraction of low angle grain boundaries and cellular structures with high density of dislocations were obtained in the as-built alloy. Dispersed Y2O3 nanoparticles were in-situ formed in the ODS NiCrFeY alloy. Most of the Y2O3 nanoparticles were located at the cellular walls and pinned with a large number of dislocations. Due to the strengthening effects by dispersed Y2O3 nanoparticles and fine cellular structures, the ODS NiCrFeY alloy showed high ultimate tensile strength of 810, 560 and 250 ​MPa at room temperature, 600 ​°C and 800 ​°C, respectively.