Application of 3D atom probe tomography to the segregation of solutes at austenite/ferrite interfaces

Segregation at the austemte/ferrite interface was successful quantified by 3D atom probe tomography (APT). Controlled decarburization caused a uniform fernte layer to grow into austemte. The fernte-austemte interface under these conditions is incoherent. Work on the Fe-Cr-C system confirmed chromium and carbon segregate at the interface. The chromium profiles measured by APT were in good agreement with EELS measurements on the same alloy. It was also verified that aging at room temperature does not affect significantly the distribution of chromium at the interface, even after ten years. However, it was confirmed that carbon remains mobile at room temperature as its distribution in the bulk phases was strongly affected by room temperature aging. Segregation peaks were found to be unexpectedly broad with FWHM neanng 4 nm after correction for known artefacts.