Dispersion Hardening Mechanism of Y₂O₃ Dispersed Ferritic Steel at High Temperature

Abstract

The threshold stress for high temperature deformation of Oxide Dispersion Strengthened (ODS) Ferritic Steel was measured by stress abruptly loading (SAL) test at 923K and was compared with the Orowan and void-hardening stresses calculated from dispersion parameters. It was found that the threshold stress obtained by SAL test decreased from the Orowan stress to the void-hardening stress as the time elapsed under load. Therefore, it is concluded that the originating mechanism of the threshold stress comes from the Srolovitz mechanism in this steel. From these results, the origin of strength anisotropy of ODS Ferritic Steel are discussed.