Effect of post annealing on microstructure and mechanical properties in Ni-free N-containing ODS steel

Journal Article · Mon Jul 01 04:00:00 EDT 2019 · Materials Characterization

DOI:https://doi.org/10.1016/j.matchar.2019.05.008· OSTI ID:1548292

Kowalska-Mori, A.; Mamiya, H.; Ohnuma, M.; Ilavsky, J.; Gilbert, E. P.; Bazarnik, P.; Kitazawa, H.; Lewandowska, M.

The precipitation behaviour of Y2O3 and MnO nanoparticles after isothermal treatment, in a Ni-free N-containing oxide dispersion strengthened (ODS) steel was studied by wide-angle X-ray scattering (WAXS), ultra-small-angle and small-angle X-ray scattering (USAXS/SAXS), small angle neutron scattering (SANS) and scanning transmission electron microscopy (STEM). Mechanical properties were investigated via tensile and micro-hardness testing. Additional precipitation occurred during annealing, in addition to the precipitates formed during sintering. The highest volume distribution of Y2O3, with average size of 6 nm, was determined by alloy contrast variation (ACV) analysis of SAXS and SANS for the sample annealed at 800 °C; this sample shows the highest hardness and ultimate tensile strength. Above that temperature, coarsening of both matrix and precipitates and depletion of nitrogen from matrix degraded the mechanical properties. The very fine nanoparticles and thermally induced dissolution of nitrogen influenced mechanical properties.

• Research Organization: Argonne National Laboratory (ANL)
• Sponsoring Organization: USDOE Office of Science - Office of Basic Energy Sciences; Warsaw University of Technology (Politechnika Warszawska)
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 1548292
• Journal Information: Materials Characterization, Journal Name: Materials Characterization Vol. 153; ISSN 1044-5803
• Country of Publication: United States
• Language: English

Related Subjects

ODS austenitic steel
alloy contrast variation (ACV)
nanoparticle
small-angle neutron scattering (SANS)
ultra-small-angle X-ray scattering (USAXS)