Three phase crystallography and solute distribution analysis during residual austenite decomposition in tempered nanocrystalline bainitic steels

• Interphase carbide precipitation due to austenite decomposition
• Tempered nanostructured bainitic steels
• High resolution transmission electron microscopy and atom probe tomography
• Paraequilibrium θ with three phase crystallographic orientation relationship

Interphase carbide precipitation due to austenite decomposition was investigated by high resolution transmission electron microscopy and atom probe tomography in tempered nanostructured bainitic steels. Results showed that cementite (θ) forms by a paraequilibrium transformation mechanism at the bainitic ferrite–austenite interface with a simultaneous three phase crystallographic orientation relationship.