Characterization of oxide dispersoids and mechanical properties of 14Cr-ODS FeCrAl alloys

Two variants of 14-Cr oxide dispersion strengthened FeCrAl alloys are fabricated by MA method. The morphology, phase and oxide/matrix interface structure of the nano-oxide dispersoids in both alloys are characterized by TEM, HRTEM, TKD and XRD. Almost all the small precipitates in Fe–14Cr-4.5Al–2W-0.4Ti-0.4Y alloy are identified as orthorhombic YAlO3 particles. In Fe–14Cr-4.5Al–2W-0.4Ti-0.3Zr-0.4Y ODS alloy, Y2(Zr0.4Ti0.6)2O7 particle with better coherent relationship with the matrix is found. Almost 23% Y2(Zr0.4Ti0.6)2O7 and YAlO3 particles coexist, resulting in refinement of average diameter of oxide dispersoids and improvement of mechanical strength. Tensile tests from room temperature to 1000 °C demonstrate the attainment of strength-toughness matching in these ODS FeCrAl alloys. The intergranular fracture after the tensile tests at elevated temperature indicates that grain boundary sliding may be the dominant mechanism for deformation. •Two ODS FeCrAl alloys with uniformly distributed nano-oxide particles, and excellent mechanical properties were fabricated.•Y2(Zr0.6Ti0.4)2O7 nanoparticles were identified in Zr-addition ODS FeCrAl alloy, having good coherency with matrix.•Dislocation density was proportional to the amount of oxide dispersoids in ODS FeCrAl alloys during mechanical processing.•Grain boundary sliding may be the dominant mechanism for deformation at elevated temperature (≥1000 ℃).