Self-repairing behavior of oxidation diffusion layer and phase transformation mechanism during tensile test of 19Cr duplex stainless steels with various Mn content

High-temperature oxidation of 19Cr duplex stainless steels with various Mn content, from 5.5 to 15 wt.%, were performed at 1100 °C in air. Self-repairing behavior of ferrite diffusion layer occurred in DSS with 10 wt.% Mn content, as the increased diffused Mn content induced more ferrite phase transformation. Ferrite diffusion layer became thicker with the increase of oxidation time and Mn content. 10 wt.% Mn content DSS exhibited exceeding 65% in elongation as transformation induced plasticity occurred in austenite phase with a sequential martensite transformation of γ → ε-martensite → α′-martensite during tensile deformation.