Electron microscopy and atom probe tomography of nanoindentation deformation in oxide dispersion strengthened steels

ebsd map section of the 100 indents showing a bimodal grain structure

Oxford Atom Probe set out to the extent of any direct link in an Oxide Dispersion Strengthened Steel sample between the Y-Ti-O dispersion and nanoindentation hardness, using electron backscatter diffraction, transmission electron microscopy (TEM) and atom probe tomography (APT).  


The local Y-Ti-O distribution did not correlate strongly with the nanohardness, indicating that the dominant hardening mechanisms were at best only weakly related to the Y-Ti-O distribution.  Instead, scanning TEM and APT confirmed that the dominant hardening mechanism was due to the grain boundary refinement, and was further enhanced by tungsten enrichment to ~3.5 at.% at grain boundaries.


You can read the full paper in volume 167 of Materials Characterization