M23C6 carbides and Cr2N nitrides in aged duplex stainless steel: A SEM, TEM and FIB tomography investigation

J.-Y. Maetz (1) , Thierry Douillard (1, 2) , Sophie Cazottes (1) , Catherine Verdu (1) , Xavier Kleber (1)

1 MATEIS - Matériaux, ingénierie et science [Villeurbanne]
2 CLYM - Consortium Lyon Saint-Etienne de Microscopie

The precipitation evolution during ageing of a 2101 lean duplex stainless steel was investigated, revealing that the precipitate type and morphology depends on the nature of the grain boundary. Triangular M23C6 carbides precipitate only at γ/δ interfaces and rod-like Cr2N nitrides precipitate at both γ/δ and δ/δ interfaces. After 15 min of ageing, the M23C6 size no longer evolves, whereas that of the Cr2N continues to evolve. For Cr2N, the morphology is maintained at γ/δ interfaces, whereas percolation occurs to form a continuous layer at δ/δ interfaces. By combining 2D and 3D characterisation at the nanoscale using transmission electron microscopy (TEM) and focused ion beam (FIB) tomography, a complete description of the precipitation evolution was obtained, including the composition, crystallographic structure, orientation relationship with the matrix phases, location, morphology, size and volume fraction. © 2016 Elsevier Ltd.

Mots clés: Carbides; Grain boundaries; Matrix phasis; Lean duplex stainless steel; Crystallographic structure; Nanotomography; Orientation relationship; Nano scale; High resolution transmission electron microscopy; Ion beams; Morphology; Nitrides; Precipitation (chemical); Solvents; Tomography; Transmission electron microscopy; Aged duplex stainless steels; Continuous layers; Stainless steel

Domaines: Matériaux

J.-Y. Maetz, Thierry Douillard, Sophie Cazottes, Catherine Verdu, Xavier Kleber. M23C6 carbides and Cr2N nitrides in aged duplex stainless steel: A SEM, TEM and FIB tomography investigation. Micron, 2016, 84, pp.43-53. ⟨10.1016/j.micron.2016.01.007⟩. ⟨hal-01804474⟩